Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Antimicrobial Resistance in Salmonella enterica Serovar Paratyphi B Variant Java in Poultry from Europe and Latin America
    Castellanos, L.R. ; Graaf-Van Bloois, Linda Van Der; Donado-Godoy, Pilar ; Veldman, K.T. ; Duarte, Francisco ; Acuna, María T. ; Jarquín, Claudia ; Weill, Francois Xavier ; Mevius, D.J. ; Wagenaar, J.A. ; Hordijk, Joost ; Zomer, Aldert L. - \ 2020
    Emerging Infectious Diseases 26 (2020)6. - ISSN 1080-6040 - p. 1164 - 1173.
    Salmonella enterica serovar Paratyphi B variant Java sequence type 28 is prevalent in poultry and poultry meat. We investigated the evolutionary relatedness between sequence type 28 strains from Europe and Latin America using time-resolved phylogeny and principal component analysis. We sequenced isolates from Colombia, Guatemala, Costa Rica, and the Netherlands and complemented them with publicly available genomes from Europe, Africa, and the Middle East. Phylogenetic time trees and effective population sizes (Ne) showed separate clustering of strains from Latin America and Europe. The separation is estimated to have occurred during the 1980s. Ne of strains increased sharply in Europe around 1995 and in Latin America around 2005. Principal component analysis on noncore genes showed a clear distinction between strains from Europe and Latin America, whereas the plasmid gene content was similar. Regardless of the evolutionary separation, similar features of resistance to β-lactams and quinolones/fluoroquinolones indicated parallel evolution of antimicrobial resistance in both regions
    Heritability estimates of the novel trait ‘suppressed in ovo virus infection’ in honey bees (Apis mellifera)
    Graaf, Dirk C. de; Laget, Dries ; Smet, Lina De; Claeys Boúúaert, David ; Brunain, Marleen ; Veerkamp, Roel F. ; Brascamp, Evert W. - \ 2020
    Scientific Reports 10 (2020)1. - ISSN 2045-2322

    Honey bees are under pressure due to abnormal high colony death rates, especially during the winter. The infestation by the Varroa destructor mite and the viruses that this ectoparasite transmits are generally considered as the bees’ most important biological threats. Almost all efforts to remedy this dual infection have so far focused on the control of the Varroa mite alone and not on the viruses it transmits. In the present study, the sanitary control of breeding queens was conducted on eggs taken from drone brood for 4 consecutive years (2015–2018). The screening was performed on the sideline of an ongoing breeding program, which allowed us to estimate the heritabilities of the virus status of the eggs. We used the term ‘suppressed in ovo virus infection’ (SOV) for this novel trait and found moderate heritabilities for the presence of several viruses simultaneously and for the presence of single viral species. Colonies that expressed the SOV trait seemed to be more resilient to virus infections as a whole with fewer and less severe Deformed wing virus infections in most developmental stages, especially in the male caste. The implementation of this novel trait into breeding programs is recommended.

    Author Correction: Global status and conservation potential of reef sharks
    MacNeil, M.A. ; Chapman, Demian D. ; Heupel, Michelle ; Simpfendorfer, Colin A. ; Heithaus, Michael ; Meekan, Mark ; Harvey, Euan ; Goetze, Jordan ; Kiszka, Jeremy ; Bond, Mark E. ; Currey-Randall, Leanne M. ; Speed, Conrad W. ; Sherman, C.S. ; Rees, Matthew J. ; Udyawer, Vinay ; Flowers, Kathryn I. ; Clementi, Gina ; Valentin-Albanese, Jasmine ; Gorham, Taylor ; Adam, M.S. ; Ali, Khadeeja ; Pina-Amargós, Fabián ; Angulo-Valdés, Jorge A. ; Asher, Jacob ; Barcia, Laura García ; Beaufort, Océane ; Benjamin, Cecilie ; Bernard, Anthony T.F. ; Berumen, Michael L. ; Bierwagen, Stacy ; Bonnema, Erika ; Bown, Rosalind M.K. ; Bradley, Darcy ; Brooks, Edd ; Brown, J.J. ; Buddo, Dayne ; Burke, Patrick ; Cáceres, Camila ; Cardeñosa, Diego ; Carrier, Jeffrey C. ; Caselle, Jennifer E. ; Charloo, Venkatesh ; Claverie, Thomas ; Clua, Eric ; Cochran, Jesse E.M. ; Cook, Neil ; Cramp, Jessica ; D’Alberto, Brooke ; Graaf, Martin de; Dornhege, Mareike ; Estep, Andy ; Fanovich, Lanya ; Farabaugh, Naomi F. ; Fernando, Daniel ; Flam, Anna L. ; Floros, Camilla ; Fourqurean, Virginia ; Garla, Ricardo ; Gastrich, Kirk ; George, Lachlan ; Graham, Rory ; Guttridge, Tristan ; Hardenstine, Royale S. ; Heck, Stephen ; Henderson, Aaron C. ; Hertler, Heidi ; Hueter, Robert ; Johnson, Mohini ; Jupiter, Stacy ; Kasana, Devanshi ; Kessel, Steven T. ; Kiilu, Benedict ; Kirata, Taratu ; Kuguru, Baraka ; Kyne, Fabian ; Langlois, Tim ; Lédée, Elodie J.I. ; Lindfield, Steve ; Luna-Acosta, Andrea ; Maggs, Jade ; Manjaji-Matsumoto, B.M. ; Marshall, Andrea ; Matich, Philip ; McCombs, Erin ; McLean, Dianne ; Meggs, Llewelyn ; Moore, Stephen ; Mukherji, Sushmita ; Murray, Ryan ; Kaimuddin, Muslimin ; Newman, Stephen J. ; Nogués, Josep ; Obota, Clay ; O’Shea, Owen ; Osuka, Kennedy ; Papastamatiou, Yannis P. ; Perera, Nishan ; Peterson, Bradley ; Ponzo, Alessandro ; Prasetyo, Andhika ; Sjamsul Quamar, L.M. ; Quinlan, Jessica ; Ruiz-Abierno, Alexei ; Sala, Enric ; Samoilys, Melita ; Schärer-Umpierre, Michelle ; Schlaff, Audrey ; Simpson, Nikola ; Smith, Adam N.H. ; Sparks, Lauren ; Tanna, Akshay ; Torres, Rubén ; Travers, Michael J. ; Zinnicq Bergmann, Maurits van; Vigliola, Laurent ; Ward, Juney ; Watts, Alexandra M. ; Wen, Colin ; Whitman, Elizabeth ; Wirsing, Aaron J. ; Wothke, Aljoscha ; Zarza-Gonzâlez, Esteban ; Cinner, Joshua E. - \ 2020
    Nature (2020). - ISSN 0028-0836

    An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

    Biosulfidogenesis mediates natural attenuation in acidic mine pit lakes
    Graaf, Charlotte M. van der; Sánchez-España, Javier ; Yusta, Iñaki ; Ilin, Andrey ; Shetty, Sudarshan A. ; Bale, Nicole J. ; Villanueva, Laura ; Stams, Alfons J.M. ; Sánchez-Andrea, Irene - \ 2020
    Microorganisms 8 (2020)9. - ISSN 2076-2607 - 26 p.
    Acidophiles - Bioremediation - Biosulfidogenesis - Lipid biomarker - Sulfate reduction - Sulfide neoformation - Sulfur disproportionation - Sulfur reduction

    Acidic pit lakes are abandoned open pit mines filled with acid mine drainage (AMD)—highly acidic, metalliferous waters that pose a severe threat to the environment and are rarely properly remediated. Here, we investigated two meromictic, oligotrophic acidic mine pit lakes in the Iberian Pyrite Belt (IPB), Filón Centro (Tharsis) (FC) and La Zarza (LZ). We observed a natural attenuation of acidity and toxic metal concentrations towards the lake bottom, which was more pronounced in FC. The detection of Cu and Zn sulfides in the monimolimnion of FC suggests precipitation of dissolved metals as metal sulfides, pointing to biogenic sulfide formation. This was supported by microbial diversity analysis via 16S rRNA gene amplicon sequencing of samples from the water column, which showed the presence of sulfidogenic microbial taxa in FC and LZ. In the monimolimnion of FC, sequences affiliated with the putative sulfate-reducing genus Desulfomonile were dominant (58%), whereas in the more acidic and metal-enriched LZ, elemental sulfur-reducing Acidianus and Thermoplasma spp., and disproportionating Desulfocapsa spp. were more abundant. Furthermore, the detection of reads classified as methanogens and Desulfosporosinus spp., although at low relative abundance, represents one of the lowest pH values (2.9 in LZ) at which these taxa have been reported, to our knowledge. Analysis of potential biomarker lipids provided evidence that high levels of phosphocholine lipids with mixed acyl/ether glycerol core structures were associated with Desulfomonile, while ceramide lipids were characteristic of Microbacter in these environments. We propose that FC and LZ function as natural bioremediation reactors where metal sulfide precipitation is mediated by biosulfidogenesis starting from elemental sulfur reduction and disproportionation at an early stage (LZ), followed by sulfate reduction at a later stage (FC).

    Time will tell : Dynamic sensory characteristics, hedonic perceptions and food-evoked emotions from first to last bite
    Bommel, Roelien van - \ 2020
    Wageningen University. Promotor(en): Markus Stieger; Kees de Graaf, co-promotor(en): Gerry Jager. - Wageningen : Wageningen University - ISBN 9789463954617 - 198
    A stepwise approach investigating salivary responses upon multisensory food cues
    Morquecho-Campos, Paulina ; Bikker, Floris J. ; Nazmi, Kamran ; Graaf, Kees de; Laine, Marja L. ; Boesveldt, Sanne - \ 2020
    Physiology and Behavior 226 (2020). - ISSN 0031-9384
    Cephalic-phase salivary response - Chewing - Gustation - Olfaction - Sight

    Exposure to sensory food cues such as smell, vision, taste and/or texture may trigger anticipatory physiological responses such as salivation, participating on adequate metabolism of the signaled food. However, the individual contribution of each sensory modality as well as the impact of particular food products on salivation and salivary composition remains unclear. Therefore, by systematically varying sensory modalities and nutrient content of food stimuli, we investigated their effect on saliva secretion, α-amylase activity and other salivary characteristics (pH level, buffering capacity, MUC5B concentration, and total protein content). Over 3 sessions, 46 normal-weight healthy participants were exposed to 12 conditions, consisting of 4 levels of sensory stimulation (odor, odor + vision, odor + vision + taste, and odor + vision + taste + mastication) and 3 types of stimuli (bread, high-in-starch; cucumber, low-in-starch; and parafilm as non-food control) during which saliva was collected. Linear mixed models showed a significant increase in salivation with increasing levels of sensory stimulation. α-amylase secretion rate increased upon the highest level of stimulation, which involved mastication, compared to odor and odor + visual level of stimulation. Other salivary characteristics varied with the level of sensory stimulation, which might be related to the total volume of salivation. The type of stimuli did not influence the saliva composition (α-amylase concentration nor other salivary components). Our findings indicate that cumulative sensory information, rather than specific (food) product, play a vital role in anticipatory salivary responses.

    Global status and conservation potential of reef sharks
    MacNeil, Aaron ; Chapman, Demian D. ; Heupel, Michelle ; Simpfendorfer, Colin A. ; Heithaus, Michael ; Meekan, Mark ; Harvey, Euan ; Goetze, Jordan ; Kiszka, Jeremy ; Bond, Mark E. ; Currey-Randall, Leanne M. ; Speed, Conrad W. ; Sherman, Samantha ; Rees, Matthew J. ; Udyawer, Vinay ; Flowers, Kathryn I. ; Clementi, Gina ; Valentin-Albanese, Jasmine ; Gorham, Taylor ; Adam, Shiham ; Khadeeja, Ali ; Pina-Amargós, Fabián ; Angulo-Valdés, Jorge A. ; Asher, Jacob ; García Barcia, Laura ; Beaufort, Océane ; Benjamin, Cecilie ; Bernard, Anthony T.F. ; Berumen, Michael L. ; Bierwagen, Stacy ; Bonnema, Erika ; Bown, Rosalind M.K. ; Bradley, Darcey ; Brooks, Edd ; Brown, Jed ; Buddo, Dayne ; Burke, Patrick ; Cáceres, Camila ; Cardeñosa, Diego ; Carrier, Jeffrey C. ; Caselle, Jennifer E. ; Charloo, Venkatesh ; Claverie, Thomas ; Clua, Eric ; Cochran, Jesse E.M. ; Cook, Neil ; Cramp, Jessica ; D’Alberto, Brooke ; Graaf, Martin de; Dornhege, Mareike ; Estep, Andy ; Fanovich, Lanya ; Farabough, Naomi F. ; Fernando, Daniel ; Flam, Anna L. ; Floros, Camilla ; Fourqurean, Virginia ; Garla, Ricardo ; Gastrich, Kirk ; George, Lachlan ; Graham, Rory ; Guttridge, Tristan ; Hardenstine, Royale S. ; Heck, Stephen ; Henderson, Aaron C. ; Hertler, Heidi ; Hueter, Robert ; Johnson, Mohini ; Jupiter, Stacy ; Kasana, Devanshi ; Kessel, Steven T. ; Kiilu, Benedict ; Kirata, Taratu ; Kuguru, Baraka ; Kyne, Fabian ; Langlois, Tim ; Lédée, Elodie J.I. ; Lindfield, Steve ; Luna-Acosta, Andrea ; Maggs, Jade ; Manjaji-Matsumoto, Mabel ; Marshall, Andrea ; Matich, Philip ; McCombs, Erin ; McLean, Dianne ; Meggs, Llewelyn ; Moore, Stephen ; Mukherji, Sushmita ; Murray, Ryan ; Kaimuddin, Muslimin ; Newman, Stephen J. ; Nogués, Josep ; Obota, Clay ; O’Shea, Owen ; Osuka, Kennedy ; Papastamatiou, Yannis P. ; Perera, Nishan ; Peterson, Bradley ; Ponzo, Alessandro ; Prasetyo, Andhika ; Quamar, Sjamsul ; Quinlan, Jessica ; Ruiz-Abierno, Alexei ; Sala, Enric ; Samoilys, Melita ; Schärer-Umpierre, Michelle ; Schlaff, Audrey ; Simpson, Nikola ; Smith, Adam N.H. ; Sparks, Lauren ; Tanna, Akshay ; Torres, Rubén ; Travers, Michael J. ; Zinnicq Bergmann, Maurits van; Vigliola, Laurent ; Ward, Juney ; Watts, Alexandra M. ; Wen, Colin ; Whitman, Elizabeth ; Wirsing, Aaron J. ; Wothke, Aljoscha ; Zarza-Gonzâlez, Esteban ; Cinner, Joshua E. - \ 2020
    Nature 583 (2020). - ISSN 0028-0836 - p. 801 - 806.

    Decades of overexploitation have devastated shark populations, leaving considerable doubt as to their ecological status1,2. Yet much of what is known about sharks has been inferred from catch records in industrial fisheries, whereas far less information is available about sharks that live in coastal habitats3. Here we address this knowledge gap using data from more than 15,000 standardized baited remote underwater video stations that were deployed on 371 reefs in 58 nations to estimate the conservation status of reef sharks globally. Our results reveal the profound impact that fishing has had on reef shark populations: we observed no sharks on almost 20% of the surveyed reefs. Reef sharks were almost completely absent from reefs in several nations, and shark depletion was strongly related to socio-economic conditions such as the size and proximity of the nearest market, poor governance and the density of the human population. However, opportunities for the conservation of reef sharks remain: shark sanctuaries, closed areas, catch limits and an absence of gillnets and longlines were associated with a substantially higher relative abundance of reef sharks. These results reveal several policy pathways for the restoration and management of reef shark populations, from direct top-down management of fishing to indirect improvement of governance conditions. Reef shark populations will only have a high chance of recovery by engaging key socio-economic aspects of tropical fisheries.

    The effect of replacing sucrose with L-arabinose in drinks and cereal foods on blood glucose and plasma insulin responses in healthy adults
    Pol, Korrie ; Graaf, Kees de; Diepeveen-de Bruin, Marlies ; Balvers, Michiel ; Mars, Monica - \ 2020
    Journal of Functional Foods 73 (2020). - ISSN 1756-4646
    Food matrix - Functionality - Glycaemic response - Insulin response - L-arabinose - Sucrose

    Glycaemic control is important in metabolic diseases such as diabetes and impaired glucose tolerance. L-arabinose inhibits the hydrolysis of sucrose into glucose and fructose. So far little is known about its functionality in different food matrices. We assessed the effect of replacing sucrose with L-arabinose in drinks and in cereal foods on blood glucose and insulin in healthy adults. Glucose and insulin responses were reduced when sucrose was replaced by L-arabinose in drinks. Replacement of sucrose in cereal foods did not affect glucose responses, however it reduced the insulin peak. L-arabinose without sucrose in a drink did not affect glucose responses. Therefore, replacing sucrose with L-arabinose is potentially a good strategy to lower glycaemic and insulin responses. However, the effects depend on the food matrix and the nutritional composition of the food. More research is warranted on the functionality of L-arabinose in different food matrices and in other populations.

    Effects of distraction on taste-related neural processing : a cross-sectional fMRI study
    Duif, Iris ; Wegman, Joost ; Mars, Monica M. ; Graaf, Cees De; Smeets, Paul A.M. ; Aarts, Esther - \ 2020
    American Journal of Clinical Nutrition 111 (2020)5. - ISSN 0002-9165 - p. 950 - 961.
    attention - consumption - distraction - fMRI - insula - orbitofrontal cortex - taste

    Background: In the current obesogenic environment we often eat while electronic devices, such as smart phones, computers, or the television, distract us. Such "distracted eating"is associated with increased food intake and overweight. However, the underlying neurocognitive mechanisms of this phenomenon are unknown. Objective: Our aim was to elucidate these mechanisms by investigating whether distraction attenuates processing in the primary and secondary taste cortices, located in the insula and orbitofrontal cortex (OFC), respectively. Methods: Forty-one healthy, normal-weight participants received fixed amounts of higher-And lower-sweetness isocaloric chocolate milk while performing a high-or low-distracting detection task during fMRI in 2 test sessions. Subsequently, we measured ad libitum food intake. Results: As expected, a primary taste cortex region in the right insula responded more to the sweeter drink (P < 0.001, uncorrected). Distraction did not affect this insular sweetness response across the group, but did weaken sweetness-related connectivity of this region to a secondary taste region in the right OFC (P-family-wise error, cluster, small-volume corrected = 0.020). Moreover, individual differences in distraction-related attenuation of taste activation in the insula predicted increased subsequent ad libitum food intake after distraction (r = 0.36). Conclusions: These results reveal a mechanism explaining how distraction during consumption attenuates neural taste processing. Moreover, our study shows that such distraction-induced decreases in neural taste processing contribute to individual differences in the susceptibility for overeating. Thus, being mindful about the taste of food during consumption could perhaps be part of successful prevention and treatment of overweight and obesity, which should be further tested in these target groups. This study was preregistered at the Open Science Framework as

    Tackling drought on high sandy ground
    Graaf, Myrjam de - \ 2020
    Outcome prediction of head and neck squamous cell carcinoma by MRI radiomic signatures
    Mes, Steven W. ; Velden, Floris H.P. van; Peltenburg, Boris ; Peeters, Carel F.W. ; Beest, Dennis E. te; Wiel, Mark A. van de; Mekke, Joost ; Mulder, Doriene C. ; Martens, Roland M. ; Castelijns, Jonas A. ; Pameijer, Frank A. ; Bree, Remco de; Boellaard, Ronald ; Leemans, C.R. ; Brakenhoff, Ruud H. ; Graaf, Pim de - \ 2020
    European Radiology (2020). - ISSN 0938-7994
    Factor analysis - Head and neck neoplasms - Magnetic resonance imaging - Prognosis

    Objectives: Head and neck squamous cell carcinoma (HNSCC) shows a remarkable heterogeneity between tumors, which may be captured by a variety of quantitative features extracted from diagnostic images, termed radiomics. The aim of this study was to develop and validate MRI-based radiomic prognostic models in oral and oropharyngeal cancer. Materials and Methods: Native T1-weighted images of four independent, retrospective (2005–2013), patient cohorts (n = 102, n = 76, n = 89, and n = 56) were used to delineate primary tumors, and to extract 545 quantitative features from. Subsequently, redundancy filtering and factor analysis were performed to handle collinearity in the data. Next, radiomic prognostic models were trained and validated to predict overall survival (OS) and relapse-free survival (RFS). Radiomic features were compared to and combined with prognostic models based on standard clinical parameters. Performance was assessed by integrated area under the curve (iAUC). Results: In oral cancer, the radiomic model showed an iAUC of 0.69 (OS) and 0.70 (RFS) in the validation cohort, whereas the iAUC in the oropharyngeal cancer validation cohort was 0.71 (OS) and 0.74 (RFS). By integration of radiomic and clinical variables, the most accurate models were defined (iAUC oral cavity, 0.72 (OS) and 0.74 (RFS); iAUC oropharynx, 0.81 (OS) and 0.78 (RFS)), and these combined models outperformed prognostic models based on standard clinical variables only (p < 0.001). Conclusions: MRI radiomics is feasible in HNSCC despite the known variability in MRI vendors and acquisition protocols, and radiomic features added information to prognostic models based on clinical parameters. Key Points: • MRI radiomics can predict overall survival and relapse-free survival in oral and HPV-negative oropharyngeal cancer. • MRI radiomics provides additional prognostic information to known clinical variables, with the best performance of the combined models. • Variation in MRI vendors and acquisition protocols did not influence performance of radiomic prognostic models.

    How oro-sensory exposure and eating rate affect satiation and associated endocrine responses-a randomized trial
    Lasschuijt, Marlou ; Mars, Monica ; Graaf, Cees de; Smeets, Paul A.M. - \ 2020
    American Journal of Clinical Nutrition 111 (2020)6. - ISSN 0002-9165 - p. 1137 - 1149.
    cephalic phase - eating behavior - eating rate - ghrelin - human - insulin - oro-sensory exposure - pancreatic polypeptide - satiation

    BACKGROUND: Longer oral processing decreases food intake. This can be attributed to greater oro-sensory exposure (OSE) and a lower eating rate (ER). How these factors contribute to food intake, and the underlying physiological mechanisms, remain unclear. OBJECTIVES: We aimed to determine the independent and simultaneous effects of OSE and ER on satiation and associated endocrine responses. METHODS: Forty participants in study 1 [mean ± SD age: 24 ± 4 y; BMI (in kg/m2): 22 ± 2] and 20 in study 2 (mean ± SD age: 23 ± 3 y; BMI: 23 ± 2) participated in a 2 × 2 randomized trial. In both studies, participants ate chocolate custard with added caramel sauce (low OSE) or caramel fudge (high OSE) and with short (fast ER) or long breaks (slow ER) in between bites, until fullness. In study 2, endocrine responses were measured during the meal. RESULTS: In study 1, participants ate (mean ± SEM) 42 ± 15 g less in the slow- than in the fast-ER condition, only within the high-OSE condition (P = 0.04). In study 2, participants ate 66 ± 21 g less in the high- than in the low-OSE condition and there were no intake differences between slow and fast ER (P = 0.35). Eight minutes after starting to eat, insulin concentrations increased by 42%-65% in all treatments compared with the control. At the end of the meal, insulin concentrations were 81% higher in the high-OSE, slow-ER than in the low-OSE, fast-ER condition (P = 0.049). Pancreatic polypeptide (PP) increased by 62%, 5 min after meal onset in the low-OSE, fast-ER condition (P = 0.005). Ghrelin concentrations did not change. CONCLUSIONS: Greater OSE increases insulin responsiveness. In contrast, PP responses are stronger when OSE is reduced and ER is fast. Insulin and PP responses may mediate the independent effects of OSE and ER on food intake. These may be beneficial eating strategies, particularly for type 2 diabetic patients, to control food intake and maintain glucose homeostasis.This trial was registered at as NL6544.

    Resting energy expenditure in cystic fibrosis patients decreases after lung transplantation, which improves applicability of prediction equations for energy requirement
    Hollander-Kraaijeveld, F.M. ; Lanen, A.S. van; Roos, N.M. de; Graaf, E.A. van de; Heijerman, H.G.M. - \ 2020
    Journal of Cystic Fibrosis (2020). - ISSN 1569-1993
    REE and REE/kg FFM significantly decrease after lung transplantation in CF patients. Prediction equations for energy requirement are inaccurate until a year after LTx. Measuring REE by indirect calorimetry is advised in CF patients before and until one year after LTx. Pre-LTx, energy requirements are at least 20% higher than predicted with common energy requirement equations.
    Sensory Evaluation of E-Liquid Flavors by Smelling and Vaping Yields Similar Results
    Krüsemann, Erna J.Z. ; Wenng, Franziska M. ; Pennings, Jeroen L.A. ; Graaf, Kees de; Talhout, Reinskje ; Boesveldt, Sanne - \ 2020
    Nicotine & Tobacco Research 22 (2020)5. - ISSN 1462-2203 - p. 798 - 805.

    INTRODUCTION: Sensory research on e-liquid flavors can be performed by means of smelling and vaping. However, data comparing smelling versus vaping e-liquid flavors are lacking. This study aims to investigate if smelling could be an alternative to vaping experiments by determining the correlation for hedonic flavor assessment between orthonasal smelling and vaping of e-liquids, for smokers and nonsmokers. METHODS: Twenty-four young adult smokers (mean age 24.8 ± 9.3) and 24 nonsmokers (mean age 24.9 ± 7.7) smelled and vaped 25 e-liquids in various flavors. Participants rated liking, intensity, familiarity, and irritation on a 100-mm Visual Analog Scale. Pearson correlations within and between smelling and vaping were calculated. Differences between user groups were calculated using t tests. RESULTS: Correlation coefficients between smelling and vaping based on mean group ratings were 0.84 for liking, 0.82 for intensity, 0.84 for familiarity, and 0.73 for irritation. Means of the within-subjects correlation coefficients were, respectively, 0.51, 0.37, 0.47, and 0.25. Correlations between smelling and vaping varied across individuals (ranging from -0.27 to 0.87) and flavors (-0.33 to 0.81). Correlations and mean liking ratings did not differ between smokers and nonsmokers. CONCLUSIONS: The strong group-level correlations between orthonasal smelling and vaping e-liquid flavors justify the use of smelling instead of vaping in future research. For example, smelling could be used to investigate differences in e-liquid flavor liking between (potential) user groups such as nicotine-naïve adolescents. The more modest within-subject correlations and variation across individuals and flavors merit caution in using smelling instead of vaping in other types of experiments. IMPLICATIONS: This study supports the use of orthonasal smelling (instead of vaping) e-liquids to measure hedonic flavor perception in some studies where vaping would be inappropriate or not feasible. Examples of research situations where smelling e-liquids may be sufficient are (1) investigating nicotine-naïve individuals (ie, nonusers), (2) investigating individuals under legal age for e-cigarette use (ie, youth and adolescents), (3) investigating brain responses to exposure of e-liquid flavors using functional magnetic resonance imaging or electroencephalogram, and (4) comparing hedonic flavor assessment between adolescent nonusers and current smokers to provide support for future regulations on e-liquid flavors.

    Foraging minds in modern environments : High-calorie and savory-taste biases in human food spatial memory
    Vries, Rachelle de; Vet, Emely de; Graaf, Kees de; Boesveldt, Sanne - \ 2020
    Appetite 152 (2020). - ISSN 0195-6663
    Cognitive bias - Eating behavior - Food spatial memory - Olfaction - Optimal foraging theory - Vision

    Human memory may show sensitivity to content that carried fitness-relevance throughout evolutionary history. We investigated whether biases in human food spatial memory exist and influence the eating behavior of individuals within the modern food environment. In two lab studies with distinct samples of 88 participants, individuals had to re-locate foods on a map in a computer-based spatial memory task using visual (Study 1) or olfactory (Study 2) cues that signaled sweet and savory high- and low-calorie foods. Individuals consistently displayed an enhanced memory for locations of high-calorie and savory-tasting foods – regardless of hedonic evaluations, personal experiences with foods, or the time taken to encode food locations. However, we did not find any clear effects of the high-calorie or savory-taste bias in food spatial memory on eating behavior. Findings highlight that content matters deeply for the faculty of human food spatial memory and indicate an implicit cognitive system presumably attuned to ancestral priorities of optimal foraging.

    Smelling our appetite? The influence of food odors on congruent appetite, food preferences and intake
    Morquecho-Campos, Paulina ; Graaf, Kees de; Boesveldt, Sanne - \ 2020
    Food Quality and Preference 85 (2020). - ISSN 0950-3293
    Congruency - Eating behavior - Explicit exposure - Macronutrients - Olfaction - Sensory-specific appetite

    We are surrounded by sensory food cues, such as odors, that may trigger (un)conscious decisions and even lead to (over)eating, it is therefore crucial to better understand the effect of food odors on behavioral responses. Food odor exposure has been shown to enhance appetite for food products with similar properties: sensory-specific appetite. This suggests that based on previous encounters with foods, we have learned to detect the nutritional content of foods, through our sense of smell. We investigated the influence of aware exposure of macronutrient-related odors on various measures of eating behavior, in a cross-over intervention study. Thirty two normal-weight healthy and unrestrained Dutch females took part in five test sessions. On each test session, they were exposed to one of five conditions (active smelling of clearly noticeable odors representing food high in carbohydrates, protein, and fat, low in calories, and a no-odor condition for 3-min) and assessed on specific appetite, food preferences and intake. Odor exposure increased congruent appetite after protein-related odor exposure. Similarly, protein-related odor exposure influenced the liking for protein foods and the preference ranking for savory products. However, food intake was not affected by smelling congruent food odors. Together this indicates that exposure to (aware) food odors may mostly influence appetite, but does not impact subsequent food intake. Moreover, appetite seems to be triggered by taste qualities rather than macronutrient information of the food, as signaled by olfactory cues. Future studies should investigate the role of awareness in more detail, to fully understand how odors might be used to steer people towards healthier food choices.

    Healthy is (not) tasty? Implicit and explicit associations between food healthiness and tastiness in primary school-aged children and parents with a lower socioeconomic position
    Heijden, Amy van der; Molder, Hedwig te; Graaf, Cees de; Jager, Gerry - \ 2020
    Food Quality and Preference 84 (2020). - ISSN 0950-3293
    Explicit associations - Food healthiness - Food tastiness - Implicit associations - Lower socioeconomic position - Primary school-aged children

    Many people implicitly (automatically) believe that unhealthy foods are tastier than healthy foods, even when they explicitly (deliberately) report that they don't. It is unclear whether this ‘unhealthy = tasty intuition’ is already present in childhood. Children from families with a lower socioeconomic position (SEP) consume poorer diets than children from families with a higher SEP. Paradoxically, populations with a lower SEP are underrepresented in research and least reached by lifestyle interventions. This study explored implicit and explicit associations between healthiness, tastiness and liking of foods in primary school-aged children and parents with a lower SEP. These associations and an estimate of dietary intake were assessed with implicit association tests and paper-and-pencil questionnaires, developed and adapted specifically for this target group. Participants were recruited at Dutch food banks. Results of 37 parent-child dyads indicated that children and parents implicitly associated healthy foods and tastiness more strongly with each other than healthy foods and not tasty (D = −0.19, p =.03 and D = −0.46, p <.001, respectively). Explicitly, parents showed similar results, while children rated pictures of unhealthy foods as tastier than pictures of healthy foods. Following the discrepancy between our hypotheses, results, and more unhealthy eating habits that often prevail in families with a lower SEP, potential explanations are discussed. We address the possibility that an internalised social norm was exposed, rather than an intrinsic belief. We propose that this research calls for in-depth qualitative research on food-related preferences and norms in the everyday life of low SEP families.

    Ultra-Processing or Oral Processing? A Role for Energy Density and Eating Rate in Moderating Energy Intake from Processed Foods
    Forde, Ciarán G. ; Mars, Monica ; Graaf, Kees De - \ 2020
    Current Developments in Nutrition 4 (2020)3. - ISSN 2475-2991
    eating rate - energy density - energy intake rate - food texture - metabolic disease - obesity - ultra-processed foods - unprocessed foods

    Background: Recent observational data and a controlled in-patient crossover feeding trial show that consumption of "ultra-processed foods" (UPFs), as defined by the NOVA classification system, is associated with higher energy intake, adiposity, and at a population level, higher prevalence of obesity. A drawback of the NOVA classification is the lack of evidence supporting a causal mechanism for why UPFs lead to overconsumption of energy. In a recent study by Hall the energy intake rate in the UPF condition (48 kcal/min) was >50% higher than in the unprocessed condition (31 kcal/min). Extensive empirical evidence has shown the impact that higher energy density has on increasing ad libitum energy intake and body weight. A significant body of research has shown that consuming foods at higher eating rates is related to higher energy intake and a higher prevalence of obesity. Energy density can be combined with eating rate to create a measure of energy intake rate (kcal/min), providing an index of a food's potential to promote increased energy intake. Objective: The current paper compared the association between measured energy intake rate and level of processing as defined by the NOVA classification. Methods: Data were pooled from 5 published studies that measured energy intake rates across a total sample of 327 foods. Results: We show that going from unprocessed, to processed, to UPFs that the average energy intake rate increases from 35.5 ± 4.4, to 53.7 ± 4.3, to 69.4 ± 3.1 kcal/min (P < 0.05). However, within each processing category there is wide variability in the energy intake rate. Conclusions: We conclude that reported relations between UPF consumption and obesity should account for differences in energy intake rates when comparing unprocessed and ultra-processed diets. Future research requires well-controlled human feeding trials to establish the causal mechanisms for why certain UPFs can promote higher energy intake.

    A feeling of full-filment : Sensory and physiological processes involved in satiation
    Lasschuijt, Marlou - \ 2020
    Wageningen University. Promotor(en): K. de Graaf, co-promotor(en): P.A.M. Smeets; M. Mars. - Wageningen : Wageningen University - ISBN 9789463952484 - 251

    Satiation is a process that occurs during eating and involves inhibitory signals at a sensory, hormonal, digestive and cognitive level. The taste and texture of food influence this process. Harder foods with an intense taste are more satiating, i.e. we need to eat less of these foods to feel full, compared to softer foods with lower taste intensity. Oro-sensory exposure (OSE), the in-mouth taste perception of food, thus plays an important role in satiation and influences meal size. However, how oro-sensory signals affect satiation is not fully understood. Therefore, the main aim of this thesis was to better understand the role of sensory signals in the physiological processes underlying satiation. To study this we investigated the effect of OSE (duration and intensity) and eating rate on food intake, associated (cephalic) endocrine responses and brain reactivity. 

    We started by investigating the independent contributions of oral processing duration and taste intensity and their combined effect on satiation (chapter 2). This was done by manipulating texture and sweet taste intensity of model foods (2x2 study design, soft and hard vs. sweet and high sweet). Hard textured model foods decreased food intake through increased OSE duration, whereas sweetness intensity did not affect intake.

    To better understand the physiology underlying the effects of oro-sensory exposure on satiation we studied the effect of texture and sweetness intensity on endocrine cephalic phase responses (chapter 3). Cephalic phase responses are neurally mediated anticipatory and conditioned responses to food cues and are considered the first phase of digestion. Insulin, pancreatic polypeptide and ghrelin responses were measured while participants modified sham fed (chew and spit) the same model foods as used in chapter 2. We expected a cephalic peak increase in these hormones 5-15 min after food exposure. However, we did not find a typical cephalic phase peak response for any of the hormones. Insulin levels tended to be higher 5 min after starting to chew but this increase could not be not be attributed to the texture or taste manipulations. In addition, we found that pancreatic polypeptide was more responsive to sweetness. Ghrelin concentrations were higher when chewing the hard texture compared to the soft texture model foods.

    Based on the results from chapter 2 and 3 we hypothesized that part of the mechanism behind the oro-sensory exposure duration effect on satiation might be eating rate. When the duration of oro-sensory exposure is increased, eating rate is slowed down. Previous studies have shown that a reduced eating rate also leads to a decrease in food intake. Additionally, we hypothesized that part of the reason why we did not find typical cephalic responses in chapter 2 was because the model foods scored ‘neutral’ on liking, whereas palatability may be important to trigger a cephalic response. We therefore investigated the effect of OSE duration and eating rate on food intake (palatable chocolate custard) and associated endocrine responses (chapter 4). Two studies were set up. In both studies subjects ate until fullness of chocolate custard with and without fudge pieces (low or high oro-sensory exposure) at two different eating rates (slow or fast eating rate). In study 1 participants received a small portion and in study 2 a larger portion. Additionally, blood samples were collected during the meal in study 2. We found that a reduced eating rate (ER) (only in the high oro-sensory exposure condition) (study 1) and increased oro-sensory exposure (study 2) decreased food intake but that this was dependent on the portion size. Eight minutes after starting to eat, insulin concentrations increased for all treatments compared to control. At the end of the meal insulin concentrations were higher in the high OSE, slow ER compared to the low OSE, fast ER condition. Pancreatic polypeptide increased at 5 min after meal onset in the low OSE, fast ER condition. There were no changes in ghrelin concentration. Greater OSE thus increases insulin responsiveness. In contrast, PP responses are stronger when OSE is reduced and ER is fast. Prandial Insulin and PP responses may mediate the independent effects of OSE and ER on food intake.

    To determine whether typical cephalic phase responses were specific to certain food cues or  sub-populations we quantified outcomes of existing literature on cephalic insulin and pancreatic polypeptide responses in a systematic review (chapter 5). In addition, we aimed to quantify the hypotheses made by previous qualitative cephalic phase reviews that cephalic responses allow for larger meal sizes, induce satiation earlier on in the meal and improve postprandial glucose homeostasis. A cephalic phase insulin and pancreatic polypeptide increase was observed in about half of all included treatments. About one fifth of the treatments induced a significant increase from baseline. The size of the cephalic insulin increase relative to spontaneous fluctuations was small and there was substantial variation in magnitude and onset time of cephalic insulin and pancreatic polypeptide responses between food cues and individuals. Based on this we concluded that cephalic phase insulin responses are small compared to spontaneous fluctuations. Although cephalic pancreatic polypeptide responses are of a larger magnitude, both show substantial variation in magnitude and onset time. Based on the current evidence, we refute the hypotheses that CPRs improve satiation and glucose homeostasis in daily life

    Finally, to determine how OSE or taste signals are processed in the brain to affect satiation we performed an fMRI study in which we measured neural reactivity to chocolate milk in the brain(stem) over the course of satiation (chapter 6). Additionally we measured gastric volume such that we could identify regions that respond solely to taste, independent of gastric distention. We found that taste activation in the parabrachial nuclei (PBN) in the brain stem, and bilateral (anterior) insula, amygdala and putamen gradually decreased as satiation increased, in line with the decrease in affective value of the chocolate milk stimuli. When subjects were hungry and completely satiated this effect could completely be explained by gastric filling, whereas this was not the case when subjects felt half full.  Responses of these brain regions are thus modulated by gastric volume and sensory satiation seems especially important early in the meal when not completely satiated.

    To conclude, we confirmed that increased OSE can decrease food intake. Insulin, PP and ghrelin cephalic phase responses do not mediate the oro-sensory exposure effect on satiation. Instead, we hypothesize that the underlying mechanisms are 1) a direct effect of oro-sensory exposure on satiation through sensory satiation and 2) an indirect effect of increased oro-sensory exposure duration which also slows down ingestion rate. This allows more time for stomach distention signals, hormone secretion, and early uptake of nutrients which are processed by the brain and induce satiation.

    Geoquímica microbiana del lago ácido y salino de la corta de la mina Brunita (La Unión, SE España)
    Sánchez-España, Javier ; Yusta, Iñaki ; Ilin, Andrey ; Graaf, Charlotte van der; Sánchez-Andrea, Irene - \ 2020
    Mine Water and the Environment 39 (2020). - ISSN 1025-9112 - p. 535 - 555.
    Acidic mine pit lakes - Bacterial sulfate reduction - Metal pollution - Natural attenuation

    We present the first study of a unique acidic lake formed in the Brunita open pit (La Unión mines, Cartagena, SE Spain). This pit lake exhibits chemical characteristics typical of AMD, such as low pH (pH 2.2–5.0) and high iron content (500–6400 mg/L total Fe). It also has some of the highest sulfate concentrations reported to date in pit lakes (26,000–38,400 mg/L SO42-) and transition metals like Mn (up to 2000 mg/L), Zn (500 mg/L), or Cu (250 mg/L). In addition, we found abnormally high concentrations of salt-forming ions (e.g. 5500 mg/L Mg, 750–1300 mg/L Cl, and 300–630 mg/L Na). The resulting high salinity (58‰) at the bottom creates a meromictic lake despite the lake’s low relative depth (9%), with an anoxic, reducing monimolimnion isolated from the oxygenated mixolimnion. In the monimolimnion, we observed decreased metal concentrations (e.g. Cu, Zn, Cd, Cr, Pb, Th). We hypothesize that these metals are being removed by interaction with biogenic H2S and subsequent precipitation as metal sulfides. Scanning electron microscopy shows sub-micron, spherical particles of ZnS in close association with cocci and rod-like bacteria. Analysis of the microbial community composition through 16S rRNA gene amplicon sequencing revealed different genera of sulfate-reducing bacteria (SRB) in the monimolimnion, including Desulfobacca, Desulfomonile, Desulfurispora, and Desulfosporosinus. Their apparent ability to reduce sulfate and selectively precipitate potentially toxic metals, and their resistance to this lake’s extreme geochemical conditions, makes these bacteria of great interest for biotechnological applications (e.g. bioremediation and biomining).

    Relating oral physiology and anatomy of consumers varying in age, gender and ethnicity to food oral processing behavior
    Ketel, Eva C. ; Wijk, Rene A. de; Graaf, Cees de; Stieger, Markus - \ 2020
    Physiology and Behavior 215 (2020). - ISSN 0031-9384
    Age - Ethnicity - Gender - Oral anatomy - Oral physiology - Oral processing behavior

    The aim of this study was to link parameters describing oral physiology and anatomy of consumers varying in age, gender and ethnicity to food oral processing behavior. Three groups of healthy consumers were compared: Dutch, Caucasian adults (18–30 yrs, n =32), Chinese, Asian adults (18–30 yrs, n =32) and Dutch, Caucasian older adults (65–85 yrs, n =32). Mastication performance, salivary flow rate (stimulated and unstimulated) and dental status were quantified to characterize oral physiology. Volume of oral cavity, tongue dimensions, facial anthropometry, height and weight were quantified to characterize anatomy. Oral processing behavior of three solid foods (carrot, cheese and sausage) was quantified by video recordings and eating rate (g/s), average consumption time (s), chews per bite (-) and average bite size (g) were determined. Dutch, Caucasian older adults had smaller volume of oral cavity, lower number of teeth and larger head width compared to Dutch, Caucasian adults. Chinese, Asian adults showed significantly higher mastication performance and larger head width compared to Dutch, Caucasian consumers, while dental status did not significantly differ between groups. Males had significantly larger volumes of oral cavity and larger head height and width compared to females. Dutch, Caucasian adults had a shorter average consumption time (s), less chews per bite and consumed the three foods with higher eating rate (g/s) compared to Dutch, Caucasian older adults. Chinese, Asian adults had a significantly longer average consumption time (s), more chews per bite, smaller average bite size (g) and lower eating rate (g/s) compared to Dutch, Caucasian adults. Twenty-one significant relationships were found between oral physiological and anatomical parameters and oral processing behavior. Body weight resulted in the largest β-values, indicating to be the anatomical parameter of largest influence on oral processing behavior. We conclude that only few oral physiological and anatomical parameters related with food oral processing behavior. We suggest that other factors, including cultural factors contribute to variation in food oral processing behavior between different consumer groups more than saliva flow, volume of oral cavity, mastication performance and dental status.

    The nutritious drink: a specialized nutrient supplement for adults and adults living with HIV in Malawi
    Rodas-Moya, Santiago - \ 2020
    Wageningen University. Promotor(en): K. de Graaf, co-promotor(en): S. de Pee. - Wageningen : Wageningen University - ISBN 9789463952200 - 183


    Undernutrition is a major problem in the world, affecting vulnerable population groups such as people living with HIV (PLHIV). Ready-to-use-therapeutic-foods or corn-soy-blends [e.g., Super Cereal (SC)] are often used to treat undernutrition among PLHIV. However, their acceptability and compliant use are not optimal. 


    To develop a culturally appropriate food nutrient supplement with sensory properties tailored to the preference, primarily of PLHIV, and potentially of adults from the general population, leading to more optimal micronutrient intake.


    We conducted two qualitative studies based on Grounded Theory. In-depth interviews with a triangulation of participants and an iterative approach to data collection were used to investigate the factors influencing preferences for food and nutrient supplements among PLHIV. Based on the results of the qualitative research, we developed eight samples of a nutritious drink.

    Next, we studied the olfactory and gustatory (chemosensory) function of PLHIV to assess whether they suffer from chemosensory losses that could explain possible differences in preferences for the eight samples of the nutritious drink. We used the Sniffin’ Sticks and Taste Strips to assess the olfactory and gustatory function of 100 PLHIV and 100 healthy adults for comparison.

    Subsequently, 100 PLHIV and 98 healthy adults evaluated the nutritious drink samples. We used hedonic scales for assessing liking, and CATA (check-all-that-apply) questions to develop a sensory characterization of the nutritious drink samples. Penalty analysis was conducted to identify the drivers of liking and disliking of the samples for subsequent product optimization.

    Our last study assessed the acceptability and ad libitum intake of the nutritious drink, RUTF, and SC. Fifty-four PLHIV evaluated the products, monadically on three consecutive days. The three food nutrient supplements were served in isocaloric portions of 1000 kcal each. Participants were instructed to consume the products ad libitum. The participants were also asked to rate their liking and wanting for each product. Time of consumption (ad libitum), the number of bites used to consume the products were also measured, and the eating rate was calculated.


    The findings from the qualitative studies indicated that PLHIV preferred a thick beverage slightly sweet and sour as a nutrient supplement. Maheu, a maize-based drink of sweet and sour flavor and a thick, gritty consistency was utilized as a benchmark for the development of the nutritious drink samples for Malawi. The results from the study on olfactory and gustatory function, suggest that PLHIV suffer from olfactory loss. However, their gustatory function was normal.

    The findings from the study using CATA questions showed clear and significant differences in the acceptability of the samples, but no significant differences in preferences between PLHIV and healthy adults. The sensory characterization of the samples made by the two groups was also similar. A preference toward sweet, somewhat sour, thick samples with a soft texture and a milky flavor was identified.

    The results from the ad libitum intake study showed a significantly higher intake of the nutritious drink (356 g) compared to RUTF (107 g) and SC-porridge (312 g). The average intake of eight essential micronutrients as a percentage of target quantities was 58 % from the nutritious drink, 33 % from RUTF, and 20 % from SC. The average caloric intake from the nutritious drink, RUTF, and SC was 507, 581, and 339 kcal, respectively.


    The combination of qualitative research and advanced techniques from sensory science allowed us to identify a product of high acceptability and to identify directions for tailoring the sensory properties of the product to the preference of the potential consumers. A more substantial weight of food and larger quantities of micronutrients were ingested from the nutritious drink compared to RUTF and SC. The nutritious drink also had a much higher eating rate compared to the semisolid supplements. These findings suggest that nutrient-dense food supplements in liquid form may be more effective than semisolid products (e.g., RUTF and SC) in treating undernutrition among PLHIV and other adults. Future research should focus on testing the efficacy of the nutritious drink in the treatment of undernutrition in comparison to RUTF and SC.

    Food preferences and intake in a population of Dutch individuals with self-reported smell loss: An online survey
    Postma, E.M. ; Graaf, C. De; Boesveldt, S. - \ 2020
    Food Quality and Preference 79 (2020). - ISSN 0950-3293
    Anosmia - Dietary intake - Eating behavior - Hyposmia - Macronutrients - Smell loss

    Olfaction plays a major role in food intake regulation. Losing the sense of smell might therefore affect eating behavior. This study investigated food preferences and intake in individuals suffering from self-reported smell loss with an online survey. Members of the Dutch Anosmia Foundation (DAF) performed the Macronutrient and Taste Preference Ranking Task (n = 71) to measure preference for foods high in fat, carbohydrates or protein and low energy foods, and for sweet and savory tastes. To assess dietary intake, adherence to the Dutch Dietary Guidelines for consumption of vegetables, fruit, fiber, fish, saturated fat, trans fatty acids, salt and alcohol was measured (n = 105). Results of the DAF participants were compared to local cohort groups. Both the control and DAF participants showed the lowest preference for carbohydrate-rich foods and highest preference for low-energy foods. Participants suffering from congenital smell loss showed an aberrant pattern, with a higher preference for fat. The total adherence score to the Dutch Dietary Guidelines was similar for the control and DAF group, but adherence scores for fiber, trans fatty acids and alcohol were lower in DAF participants. Overall, no major significant differences in food preferences and intake were found for participants who lost their sense of smell during life. Participants suffering from congenital smell loss did show changes in food preferences, suggesting they are potentially more taste-oriented during eating. Together these results show the importance of tailored advice on dietary intake for this patient group.

    Exploring in vitro gastric digestion of whey protein by time-domain nuclear magnetic resonance and magnetic resonance imaging
    Deng, Ruoxuan ; Janssen, Anja E.M. ; Vergeldt, Frank J. ; As, Henk Van; Graaf, Cees de; Mars, Monica ; Smeets, Paul A.M. - \ 2020
    Food Hydrocolloids 99 (2020). - ISSN 0268-005X
    Gastric digestion - Gel - In vitro - MRI - Time-domain NMR - Whey protein

    Gastric digestion is crucial for protein breakdown. Although it has been widely studied with in vitro models, verification in vivo remains a big challenge. Magnetic resonance imaging (MRI) has the potential to bridge this gap. Our objective was to use the transverse relaxation time (T2) and rate (R2 = T2 −1) to monitor hydrolysis of protein-rich food during in vitro gastric digestion. Whey protein solution and heat-induced hydrogels were digested by means of simulated gastric fluid (SGF). Free amino groups (–NH2 groups) and protein concentration in the supernatant were measured. T2 and R2 of the digestion mixture were determined by time-domain nuclear magnetic resonance (TD-NMR) and MRI. Subsequently, relative amplitudes (TD-NMR) for different T2 values and T2 distribution (MRI) were determined. For the solution, protein concentration and T2 did not change during digestion. For the gels, water in supernatant and gel phase could be discriminated on the basis of their T2 values. During digestion, R2 of supernatant correlated positively with protein (–NH2 groups) concentration in SGF. Also, the decrease in relative amplitude of gel fraction correlated linearly with the increase of supernatant protein concentration. MRI T2-mapping showed similar associations between R2 of supernatant and protein (–NH2 groups) concentration. In conclusion, T2-measurements by TD-NMR and MRI can be used to monitor in vitro gastric digestion of whey protein gels; TD-NMR measurements contributed to interpreting the MRI data. Thus, MRI has high potential for monitoring in vivo gastric digestion and this should be further pursued.

    Non-fasting bioelectrical impedance analysis in cystic fibrosis: Implications for clinical practice and research
    Hollander-Kraaijeveld, F.M. ; Lindeman, Y. ; Roos, N.M. de; Burghard, M. ; Graaf, E.A. van de; Heijerman, H.G.M. - \ 2020
    Journal of Cystic Fibrosis 19 (2020)1. - ISSN 1569-1993 - p. 153 - 158.
    Anthropometry - Body composition - Cystic fibrosis - FEV1%pred - Non-fasting - Single frequency bioelectrical impedance analysis

    Background: Nutritional status affects pulmonary function in cystic fibrosis (CF) patients and can be monitored by using bioelectrical impedance analysis (BIA). BIA measurements are commonly performed in the fasting state, which is burdensome for patients. We investigated whether fasting is necessary for clinical practice and research. Methods: Fat free mass (FFM) and fat mass (FM) were determined in adult CF patients (n = 84) by whole body single frequency BIA (Bodystat 500) in a fasting and non-fasting state. Fasting and non-fasting BIA outcomes were compared with Bland-Altman plots. Pulmonary function was expressed as Forced Expiratory Volume at 1 s percentage predicted (FEV1%pred). Comparability of the associations between fasting and non-fasting body composition measurements with FEV1%pred was assessed by multiple linear regression. Results: Fasting FFM, its index (FFMI), and phase angle were significantly lower than non-fasting estimates (−0.23 kg, p = 0.006, −0.07 kg/m2, p = 0.002, −0.10°, p = 0.000, respectively). Fasting FM and its index (FMI) were significantly higher than non-fasting estimates (0.22 kg, p = 0.008) 0.32%, p = 0.005, and 0.07 kg/m2, (p = 0.005). Differences between fasting and non-fasting FFM and FM were <1 kg in 86% of the patients. FFMI percentile estimates remained similar in 83% of the patients when measured after nutritional intake. Fasting and non-fasting FFMI showed similar associations with FEV1%pred (β: 4.3%, 95% CL: 0.98, 7.70 and β: 4.6%, 95% CI: 1.22, 8.00, respectively). Conclusion: Differences between fasting and non-fasting FFM and FM were not clinically relevant, and associations with pulmonary function remained similar. Therefore, BIA measurements can be performed in a non-fasting state.

    Indoor-visteelt verhoogt rendement
    Boedijn, Alexander ; Graaf, Marcel van de - \ 2019
    Surveillance van Listeria monocytogenes in Nederland, 2018
    Friesema, I.H.M. ; Kuiling, Sjoerd ; Heck, M. ; Wullings, Bart ; Voort, Menno van der; Freudenburg-de Graaf, W. ; Ende, A. van den; Franz, E. - \ 2019
    Infectieziekten bulletin 30 (2019)6. - ISSN 0925-711X
    Sinds 2008 is listeriose meldingsplichtig. In 2018 zijn 78 patiënten met listeriose geregistreerd, waaronder 7 zwangere vrouwen (9%). Vier volwassenen zijn ten gevolge van de infectie overleden (6%). De meeste listeriosepatiënten hadden ernstig onderliggende aandoeningen en/of gebruikten immunosuppressiva en/of maagzuurremmers. Een aantal risicoproducten werden in 2018 vaker door patiënten geconsumeerd dan in voorgaande jaren. De meest opvallende stijgers zijn corned beef, gerookte zalm, garnalen en kibbeling/lekkerbek. Whole-genome-sequencing (WGS)-gegevens lieten een aantal clusteringen van patiëntisolaten zien en ook waren een aantal patiëntisolaten geclusterd met voedselisolaten. De meeste clusters bestaan uit patiënten uit verschillende jaren bij wie (vrijwel) identieke stammen zijn aangetoond. Er lijkt dus sprake te zijn van stammen die vanuit persisterende bronnen levensmiddelen besmetten. WGS maakt deze nieuwe inzichten mogelijk en biedt ook nieuwe mogelijkheden om de ziektelast van listeriose verder te verminderen vanwege het grotere vermogen om verbanden te leggen tussen de levensmiddelen en patiënten.

    Listeria monocytogenes is een bacterie die overal in het milieu voorkomt. De bacterie kan zelfs onder ongunstige omstandigheden zoals droogte en lage temperaturen, overleven en groeien. Infectie bij de mens gebeurt voornamelijk via voedsel dat besmet wordt vanuit de productieomgeving. Het aantal mensen dat listeriose oploopt is niet heel groot, maar de ziektelast is door de ernst van de ziekte hoog. (1, 2) In Nederland bestaat er sinds 2005 een laboratoriumsurveillance voor L. monocytogenes en een aangifteplicht sinds december 2008. Sinds 2017 wordt WGS toegepast als standaard typeringsmethode. Daarnaast worden door de Nederlandse Voedsel en Waren Autoriteit (NVWA) jaarlijks diverse risicovolle voedingsmiddelen op L. monocytogenes onderzocht. In deze rapportage presenteren we de gezamenlijke resultaten van 2018 en vergelijken die met elkaar en ten opzichte van voorgaande jaren.
    Healthy is (not) tasty? Implicit and explicit associations between food healthiness andtastiness in primary school-aged children and parents with a lower socioeconomic position
    Heijden, A. van der; Molder, H.F.M. te; Graaf, C. de; Jager, G. - \ 2019
    - 1 p.
    Growth, maturation, sex-ration, length and age of European eel (Anguilla anguilla) in the Netherlands
    Hammen, T. van der; Wolfshaar, K.E. van de; Graaf, M. de; Leeuw, Joep de - \ 2019
    In: Eels biology, monitoring, management, culture and exploitation / Coulson, Paul, Don, Andy, 5m Publishing - ISBN 9781789180695 - p. 111 - 118.
    Spatial distribution, relative abundance and size composition of reef-associated sharks on St Eustatius, Saba and the Saba Bank (Caribbean Netherlands)
    Stoffers, Twan ; Graaf, Martin de; Machiels, Marcel ; Nagelkerke, Leo - \ 2019
    Spatial distribution, relative abundance and size composition of reef-associated sharks on St Eustatius, Saba and the Saba Bank (Caribbean Netherlands)
    Stoffers, Twan ; Graaf, Martin de; Machiels, Marcel ; Nagelkerke, Leo - \ 2019
    elasmobranchs - conservation - habitat preference
    The aim of this study was to undertake a baseline-survey on the spatial distribution, relative abundance and size composition of reef-associated sharks in St Eustatius, Saba and the Saba Bank, windward islands of the Caribbean Netherlands. From 2012 to 2014 376 sites were surveyed with stereo Baited Remote Underwater Video (sBRUV) deployments. Videos were analysed for shark presence and individual sharks were measured using stereo-video, enabling accurate length measurements. A total of 153 sharks belonging to six species were recorded. Mean probability of observing at least one shark per recording is 0.29. In 4.3% of the video deployments two or more sharks were observed. Nurse shark was the most frequently observed species (n = 78) followed by Caribbean reef shark (n = 62), blacktip reef shark (n = 6), tiger shark (n = 5), great hammerhead shark (n = 1) and silky shark (n = 1). Significant spatial differences in geographic location were found for abundances of G. cirratum and C. perezi. Mean probability of observing these shark species on St Eustatius and the Saba Bank was found to be twice as high as compared to Saba. Habitat complexity and depth also had significant effects on total shark abundances. Mean probability of observing a reef-associated shark increased with habitat complexity and decreased with depth. The effect of management zone was not significant. Individuals of G. cirratum were significantly larger on the Saba Bank and in sites with low habitat complexity. Judging by total shark abundances, the shark populations of the Saba Bank, Saba and St Eustatius appear to be in reasonably healthy state compared to other areas in the Caribbean. The vast majority of observed sharks were juveniles, indicating that these shallow waters may be used as nursery areas.
    E-liquid flavor preferences and individual factors related to vaping : A survey among dutch never-users, smokers, dual users, and exclusive vapers
    Romijnders, Kim A.G.J. ; Krüsemann, Erna J.Z. ; Boesveldt, Sanne ; Graaf, Kees de; Vries, Hein de; Talhout, Reinskje - \ 2019
    International Journal of Environmental Research and Public Health 16 (2019)23. - ISSN 1661-7827
    Attitude - Deliberation - Electronic cigarettes - Flavors - Knowledge - Perceived susceptibility - Preference - Smoking - Vaping

    Appealing product characteristics, such as flavors, may stimulate e-cigarette use. While switching to e-cigarettes may reduce harm for smokers, concerns exist about e-cigarette use among neversmokers. The role of flavors in the decision to switch to or refrain from vaping is unclear. This study used a bottom–up approach to investigate the relation between flavor preferences and individual factors related to vaping between various user groups. A cross-sectional survey was conducted among never-users (n = 407), smokers (n = 138), dual users (n = 122), and exclusive vapers (n = 61) in the Netherlands. Demographics, attractiveness of product characteristics, flavor preferences, and individual factors related to vaping (knowledge, trust, perceived susceptibility, attitude, social influence, deliberation, and intention) were assessed. The availability of different flavors was the most attractive characteristic of ecigarettes. Dual users and exclusive vapers had most often used tobacco and menthol/mint flavors when they first started vaping. Compared to dual users, exclusive vapers currently used more fruit and sweet flavors. Never-users who were interested in trying an e-liquid flavor had more knowledge about and a more positive attitude towards e-cigarettes. Smokers who were interested in trying a flavor had a more positive attitude towards e-cigarettes and experienced the social influence towards not using e-cigarettes as less strong than those who did not want to try any flavor. Hence, individual factors related to vaping differed depending on whether never-users and smokers wanted to try an e-liquid flavor. This means that flavors may moderate differences found in individual factors related to vaping, or vice versa.

    Nearly 20 000 e-liquids and 250 unique flavour descriptions: An overview of the Dutch market based on information from manufacturers
    Havermans, Anne ; Krüsemann, Erna J.Z. ; Pennings, Jeroen ; Graaf, Kees De; Boesveldt, Sanne ; Talhout, Reinskje - \ 2019
    Tobacco Control (2019). - ISSN 0964-4563
    consumer appeal - e-cigarettes - e-liquid manufacturing - e-liquids - flavor descriptions - marketing - tobacco product directive

    Objectives: Flavours increase attractiveness of electronic cigarettes and stimulate use among vulnerable groups such as non-smoking adolescents. It is important for regulators to monitor the market to gain insight in, and regulate the range of e-liquid flavours that is available to consumers. E-liquid manufacturers are required to report key product information to authorities in the European Member States in which they plan to market their products. This information was used to provide an overview of e-liquid flavour descriptions marketed in the Netherlands in 2017. Methods: Two researchers classified 19 266 e-liquids into the 16 main categories of the e-liquid flavour wheel, based on information from four variables in the European Common Entry Gate system. Flavour descriptions were further specified in subcategories. Results: For 16 300 e-liquids (85%), sufficient information was available for classification. The categories containing the highest number of e-liquids were fruit (34%), tobacco (16%) and dessert (10%). For all e-liquids, excluding unflavoured ones, 245 subcategories were defined within the main categories. In addition to previously reported subcategories, various miscellaneous flavours such as sandwich, buttermilk and lavender were identified. Conclusions: In 2017, ∼20 000 e-liquids were reported to be marketed in the Netherlands, in 245 unique flavour descriptions. The variety of marketed flavour descriptions reflects flavour preference of e-cigarette users as described in literature. Our systematic classification of e-liquids by flavour description provides a tool for organising the huge variety in market supply, serves as an example for other countries to generate similar overviews and can support regulators in developing flavour regulations.

    Letter of protest on new food label
    Graaf, Kees de - \ 2019
    #3 Waarom je beter langzaam kunt eten dan een dieethype volgen
    Graaf, C. de - \ 2019
    An E-Liquid Flavor Wheel: A Shared Vocabulary Based on Systematically Reviewing E-Liquid Flavor Classifications in Literature
    Krüsemann, Erna J.Z. ; Boesveldt, Sanne ; Graaf, Kees de; Talhout, Reinskje - \ 2019
    Nicotine & Tobacco Research 21 (2019)10. - ISSN 1462-2203 - p. 1310 - 1319.

    INTRODUCTION: E-liquids are available in a high variety of flavors. A systematic classification of e-liquid flavors is necessary to increase comparability of research results. In the food, alcohol, and fragrance industry, flavors are classified using flavor wheels. We systematically reviewed literature on flavors related to electronic cigarette use, to investigate how e-liquid flavors have been classified in research, and propose an e-liquid flavor wheel to classify e-liquids based on marketing descriptions. METHODS: The search was conducted in May 2017 using PubMed and Embase databases. Keywords included terms associated with electronic cigarette, flavors, liking, learning, and wanting in articles. Results were independently screened and reviewed. Flavor categories used in the articles reviewed were extracted. RESULTS: Searches yielded 386 unique articles of which 28 were included. Forty-three main flavor categories were reported in these articles (eg, tobacco, menthol, mint, fruit, bakery/dessert, alcohol, nuts, spice, candy, coffee/tea, beverages, chocolate, sweet flavors, vanilla, and unflavored). Flavor classifications of e-liquids in literature showed similarities and differences across studies. Our proposed e-liquid flavor wheel contains 13 main categories and 90 subcategories, which summarize flavor categories from literature to find a shared vocabulary. For classification of e-liquids using our flavor wheel, marketing descriptions should be used. CONCLUSIONS: We have proposed a flavor wheel for classification of e-liquids. Further research is needed to test the flavor wheels' empirical value. Consistently classifying e-liquid flavors using our flavor wheel in research (eg, experimental, marketing, or qualitative studies) minimizes interpretation differences and increases comparability of results. IMPLICATIONS: We reviewed e-liquid flavors and flavor categories used in research. A large variation in the naming of flavor categories was found and e-liquid flavors were not consistently classified. We developed an e-liquid flavor wheel and provided a guideline for systematic classification of e-liquids based on marketing descriptions. Our flavor wheel summarizes e-liquid flavors and categories used in literature in order to create a shared vocabulary. Applying our flavor wheel in research on e-liquids will improve data interpretation, increase comparability across studies, and support policy makers in developing rules for regulation of e-liquid flavors.

    Secret for getting fussy kids to eat their greens? A variety of veg
    Graaf, C. de - \ 2019
    Baby's first bites: a randomized controlled trial to assess the effects of vegetable-exposure and sensitive feeding on vegetable acceptance, eating behavior and weight gain in infants and toddlers
    Veek, S.M.C. van der; Graaf, C. de; Vries, J.H.M. de; Jager, G. ; Vereijken, C.M.J.L. ; Weenen, H. ; Winden, N. van; Vliet, M.S. van; Schultink, J.M. ; Wild, V.W.T. de; Janssen, S. ; Mesman, J. - \ 2019
    BMC Pediatrics 19 (2019)1. - ISSN 1471-2431 - 1 p.
    Complementary feeding - Infant - Responsive feeding - Self-regulation of energy intake - Toddler - Vegetable exposure - Vegetables

    BACKGROUND: The start of complementary feeding in infancy plays an essential role in promoting healthy eating habits. Evidence shows that it is important what infants are offered during this first introduction of solid foods: e.g. starting exclusively with vegetables is more successful for vegetable acceptance than starting with fruits. How infants are introduced to solid foods also matters: if parents are sensitive and responsive to infant cues during feeding, this may promote self-regulation of energy intake and a healthy weight. However, the effectiveness of the what and the how of complementary feeding has never been experimentally tested in the same study. In the current project the what and how (and their combination) are tested in one study to determine their relative importance for fostering vegetable acceptance and self-regulation of energy intake in infants. METHODS: A four-arm randomized controlled trial (Baby's First Bites (BFB)) was designed for 240 first-time Dutch mothers and their infants, 60 per arm. In this trial, we compare the effectiveness of (a) a vegetable-exposure intervention focusing on the what in complementary feeding; (b) a sensitive feeding intervention focusing on the how in complementary feeding, (c) a combined intervention focusing on the what and how in complementary feeding; (d) an attention-control group. All mothers participate in five sessions spread over the first year of eating solid foods (child age 4-16 months). Primary outcomes are vegetable consumption, vegetable liking and self-regulation of energy intake. Secondary outcomes are child eating behaviors, child anthropometrics and maternal feeding behavior. Outcomes are assessed before, during and directly after the interventions (child age 18 months), and when children are 24 and 36 months old. DISCUSSION: The outcomes are expected to assess the impact of the interventions and provide new insights into the mechanisms underlying the development of vegetable acceptance, self-regulation and healthy eating patterns in infants and toddlers, as well as the prevention of overweight. The results may be used to improve current dietary advice given to parents of their young children on complementary feeding. TRIAL REGISTRATION: The trial was retrospectively registered during inclusion of participants at the Netherlands National Trial Register (identifier NTR6572 ) and at ( NCT03348176 ). Protocol issue date: 1 April 2018; version number 1.

    Biology, monitoring, and management of a tropical marine gastropod: the Queen conch (Lobatus gigas) in the Caribbean
    Boman, B.E. - \ 2019
    Wageningen University. Promotor(en): A.C. Smaal, co-promotor(en): L.A.J. Nagelkerke; M. de Graaf. - Wageningen : Wageningen University - ISBN 9789463439909 - 207

    The marine gastropod queen conch (Lobatus gigas), found throughout the Wider Caribbean Region, supports one of the most important fisheries in the region. However, several biological characteristics (e.g. density-dependent mating and survival, slow-moving, a preference for shallow depths, and aggregating behaviour during the reproductive season) make the species particularly vulnerable to overfishing. The heavy exploitation of queen conch throughout large parts of its natural range, as well as degradation of juvenile and adult habitats, also has in many areas led to a reduction in population densities to unsustainable levels to a point where mating success can be negatively affected. In addition, a new invasive seagrass species (H. stipulacea) has already caused significant alterations to the structure of native seagrass habitats which are in many parts of the Caribbean important to juvenile conch, providing both nutrition and protection from predators. However, the impacts of this invasive seagrass on life-history parameters such as growth and survival remain unknown.

    Although many Caribbean nations have implemented policies with regard to queen conch protection and exploitation, recovery of overfished populations has been slow. These measures, however, are still mostly not harmonized among nations and often based on outdated and limited biological information. Management of queen conch is also often complicated by difficulties in data acquisition, partly caused by the logistically demanding and relatively expensive surveying of conch. Conventional survey methods using scuba are also limited to ca. 25 m depth due to safety limitations, making them unsuitable for collecting data across the entire depth range of conch, which extends to 60 m.

    The main objectives of this study were to address knowledge gaps of the biology and ecology of the queen conch so that the distribution and dynamics of this species in relation to its environment are better understood. Such information will further improve our knowledge of marine gastropod biology in general, as well as our understanding of the effects of direct and indirect human-induced pressures on queen conch in the Caribbean. In addition, this study aimed to tackle some methodological shortcomings in the surveying and assessment of queen conch. Ultimately, these findings could be instrumental in the management and conservation of the species.

    Reproductive characteristics are important biological reference points for the management of species. To improve the knowledge of queen conch reproductive biology (i.e. size-at-maturity and reproductive season), evaluation and comparison of the relationship between shell lip thickness and maturity in queen conch throughout the Wider Caribbean Region, using histological analysis of queen conch gonads was carried out. Furthermore, the influence of seawater temperature on the length of the reproductive season was investigated (chapter 2). We demonstrate a clear positive relationship between the thickness of the shell lip and the onset of maturity in queen conch, and that maturity occurs following the development of the lip. Lip thickness at 50% maturity (LT50) of both females and males varied between different locations in the Caribbean, although it did not correspond with variation in water temperature. In most cases, females had a larger LT50 than males indicating sexual dimorphism. Locations with a relatively high variation in water temperature had a significantly shorter reproductive season. The implementation of adequate minimum size regulation based on lip thickness (ca. 15 mm) and a Caribbean wide seasonal closure (May–September) using the most recent biological information from this study, taking into consideration the local differences in LT50 and reproductive season, will assist in developing a long-term sustainable queen conch fishery in the Caribbean.

    To address the methodological shortcomings in the surveying of queen conch, a novel towed video method (TVM) was developed and compared with a conventional survey method (i.e. belt transect [BT] using scuba divers) in a series of calibration transects in two different habitats (i.e. high complexity (HC) and low complexity (LC)) (chapter 3). In both habitats, adult live queen conch had similar counts with both methods. Adult dead conch were not mistaken for live conch and the results validate the use of TVM as a reliable sampling tool to estimate densities of live adult conch in both HC and LC habitats throughout the species’ depth range.

    In chapter 4, the spatial distribution of adult queen conch and how it varies in response to a number of known abiotic and biotic variables between sites which vary in environmental conditions was examined. By combining TVM with conventional belt-transects, a more comprehensive survey of conch abundance was performed at three sites in the Eastern Caribbean (Anguilla, St Eustatius, Saba Bank). Adult conch appeared in patchy distributions, mostly caused by spatial dependency, which was likely related to aggregating behaviour during spawning events. Environmental variables, such as algae cover, distance to the open ocean, and depth showed important non-linear effects on conch abundance, although these differed among sites. The proportion of reef and sand cover had important negative effects on conch abundance at all sites. High densities (>100 /ha) of adult conch were found only at depths >17 m at all three sites. The lack of strong generic location over-crossing relationships between abiotic and biotic factors and adult conch abundance and distribution is likely partly due to this spatial dependency, as well as different location-specific factors that affect different stages of the conch’s life-history. Furthermore, the results indicate that intermediate and deep areas (ca. 17 – 45 m) contain most of the reproductive output of conch in the survey sites and are therefore highly important for reproductive capacity. Thus, surveying areas at depths beyond the practical limitation of divers (<25 m) are of great importance to obtain more reliable population estimates.

    To provide a first insight into the possible impact of an invasive seagrass species (H. stipulacea) on queen conch, the diet and growth of juvenile conch in both native, mixed, and invasive seagrass beds was examined using stable isotope analysis and an in situ growth enclosure experiment (chapter 5). Organic material in the sediment (i.e. benthic diatoms and particulate organic matter [POM]) was found to be the most important source of carbon and nitrogen for juvenile queen conch in all three habitats investigated, and there was a significantly higher probability of positive growth in the native seagrass compared to the invasive seagrass. Due to the importance of the organic material in the sediment as a source of nutrition for juvenile conch, limited access to the sediment in the invasive seagrass can potentially cause inadequate nutritional conditions to sustain high growth rates. Thus, it is likely that there is a negative effect on juvenile queen conch growth currently inhabiting invasive seagrass beds, compared to native seagrass beds, when other potential sources of nutrition are not available. Although much uncertainty still exists regarding the effects of H. stipulacea on the population dynamics on queen conch, if lower growth rates in invasive seagrass beds is a general pattern, it would have ramifications for both births and deaths of conch and the overall carrying capacity of conch populations in the Caribbean.

    A better understanding of the spatial genetic structure (SGS) and the factors driving contemporary patterns of gene flow and genetic diversity of queen conch are fundamental for developing conservation and management plans for marine fisheries. A detailed study of SGS and genetic diversity was therefore performed using population genetic and multivariate analyses (chapter 6). Our study found that queen conch does not form a single panmictic population in the greater Caribbean. Significant levels of genetic differentiation were identified between Caribbean countries, within Caribbean countries, and among sites. Gene flow over the spatial scale of the entire Caribbean basin is constrained by oceanic distance, which may impede the natural recovery of overfished queen conch populations. Our results suggest a careful blend of local and international management will be required to ensure long-term sustainability for the species.

    This study has provided new insights into queen conch biology and population dynamics as well as methodological shortcomings so that the distribution and dynamics of this species in relation to its environment are better understood. Ultimately, the findings from this study can contribute to improving the management and conservation of the species. However, the species will in the future face new challenges, due to expected changes in abiotic and biotic factors, such as temperature, ocean currents, and seagrass species composition. As body temperature and thus their physiological functions (e.g. growth) are directly dependent on environmental condition in this ectotherm species, it is particularly vulnerable to climate change (Dillon et al. 2010). Consequently, life-history parameters (e.g. size-at-maturity, reproductive season, growth rate, spatial genetic structure) of queen conch should not be considered rigid as these can be expected to change in the short and long-term, putting an unknown time limit to the relevance of the current biological knowledge of these parameters. However, there is still much uncertainty regarding what degree queen conch and other species can adapt to environmental changes induced by climate change and invasive species. Therefore, commitment to long-term research and updates in current biological knowledge, life-history parameters and population dynamics of queen conch throughout its range will be required to adjust subsequent management and conservation strategies to ensure the long-term sustainability of the species.

    Impact of food odors signaling specific taste qualities and macronutrient content on saliva secretion and composition
    Morquecho-Campos, Paulina ; Bikker, Floris J. ; Nazmi, Kamran ; Graaf, Kees de; Laine, Marja L. ; Boesveldt, S. - \ 2019
    Appetite 143 (2019). - ISSN 0195-6663
    Cephalic phase response - Olfaction - Salivary protein - Salivation - Smell

    Olfactory food cues can induce appetite for similar food products in humans. Odors may thus signal essential information about a foods’ composition such as taste or even macronutrient content and may stimulate specific physiological responses in anticipation of food intake. Several studies have shown that sensory food cues could stimulate saliva secretion. However, potential differences between food odors in their effect on saliva secretion, or the effects of olfactory stimulation on changes in saliva composition remain to be elucidated. To gain more insight, we conducted two studies to determine the influence of various odors, representing different taste qualities (study 1) and macronutrients (study 2), on salivary biomarkers. In study 1, 36 participants were randomly exposed to no-odor, non-food, and odors signaling sweet, savory, and sour taste. In study 2, 60 participants were randomly exposed to no-odor, non-food, and odors signaling carbohydrates, protein, fat, and low-calorie food. For each condition, whole-mouth saliva was collected and saliva secretion rate determined. Furthermore, we determined mouth-watering perception (subjective salivation), visco-elasticity (study 1 only), mucin concentration, α-amylase and lingual lipase activity (study 2 only). For both studies, linear mixed model analyses showed that saliva secretion rate significantly increased by food odor exposure compared to no-odor and non-food conditions. However, no changes in salivary composition were observed. These findings indicate that food odors play a crucial role in anticipatory saliva responses and can thereby affect subsequent eating behavior.

    Multiple vs Single Target Vegetable Exposure to Increase Young Children's Vegetable Intake
    Poelman, Astrid A.M. ; Delahunty, Conor M. ; Broch, Maeva ; Graaf, C. de - \ 2019
    Journal of Nutrition Education and Behavior 51 (2019)8. - ISSN 1499-4046 - p. 985 - 992.
    acceptance - repeated exposure - variety - vegetable intake - young children

    Objective: To evaluate the effectiveness of repeated exposure to multiple vs single target vegetables in increasing young children's vegetable intake. Methods: A pilot randomized controlled trial (children aged 4–6 years, n = 32) was conducted, which exposed children at home 15 times over 5 weeks to either 1 (single target) or 3 (multiple target) vegetables. A comparison group did not change eating habits. Vegetable intake was measured by (1) a dinner meal consumed at research facilities, (2) 3-day weighed food records, and (3) usual vegetable intake (parent report). Measures were collected at baseline and either immediately after intervention (1), at 3-month follow-up (3) or both (2). Results: There were no differences between groups at baseline in vegetable intake. Usual vegetable intake increased in the multiple target group from.6 to 1.2 servings/d and did not change in other groups (P =.02). Food record data were not significant but underpowered. Vegetable intake from dinner meals was not significantly different between groups. Conclusions and Implications: Exposure to multiple vegetables simultaneously may be more effective than a single vegetable to increase young children's intake. Larger scale research is recommended to confirm the effectiveness of offering variety in exposure and to enhance the understanding of the mechanisms involved.

    Small food texture modifications can be used to change oral processing behaviour and to control ad libitum food intake
    Mosca, Ana Carolina ; Pohlenz Torres, Armando ; Slob, Evalien ; Graaf, Kees de; McEwan, Jean A. ; Stieger, Markus - \ 2019
    Appetite 142 (2019). - ISSN 0195-6663
    Eating rate - Food intake - Food texture - Oral processing behaviour - Satiation

    Little is known whether small modifications of food texture are sufficient to influence satiation. This study used four iso-caloric yogurts differing in viscosity (low/high) and granola particle size (small/large) to investigate the influence of small texture modifications on oral processing behaviour, eating rate and ad libitum intake. Yogurt viscosity differed by a factor of 1.57x to 1.81x. Granola particle size was 6 mm and 12 mm (2-fold difference). Granola particle concentration based on weight was constant (15% w/w). Oral processing behaviour was quantified by video recording consumers eating yogurt ad libitum (n = 104). Ratings for appetite, liking and product familiarity were also quantified. A decrease in yogurt viscosity significantly decreased spoon size, number of chews per spoon and oral exposure time per spoon but did not significantly affect eating rate and ad libitum intake. A decrease in granola particle size from 12 mm to 6 mm at constant weight concentration significantly increased number of chews per spoon and decreased spoon size, eating rate and ad libitum intake without affecting liking. The differences in eating rate and ad libitum intake between yogurts containing small and large granola particles were 5 g/min (7%) and 17 g (5%), respectively. We suggest that the volume of granola particles added to the yogurt and not the size of particles per se was the driver of oral processing behaviour. We conclude that relatively small modifications in yogurt texture, especially granola particle size, are sufficient to change oral processing behaviour and ad libitum intake. These findings demonstrate that small texture modifications of foods, such as the size of granola particles added to yogurt, can be used to modulate eating rate and food intake within a meal.

    Colouring perception: Package colour cues affect neural responses to sweet dairy drinks in reward and inhibition related regions
    Tijssen, Irene O.J.M. ; Smeets, Paul A.M. ; Goedegebure, Robert P.G. ; Zandstra, Elizabeth H. ; Graaf, Cees de; Jager, Gerry - \ 2019
    Appetite 142 (2019). - ISSN 0195-6663
    BOLD fMRI - Health interest - Impulsivity - Package colour - Product perception

    Extrinsic product cues such as package colour may change product perception and perceived reward value during product evaluation. Healthier foods (i.e., ‘light’, sugar- or fat-reduced) often have different packages than regular products, e.g., they may be less vibrantly coloured. People vary in their degree of health-interest and self-control ability and may be affected differently by package colour. This study assesses the extent to which package colour and participant characteristics interact and influence product perception and brain responses. Thirty-four healthy females performed a functional MRI task in which they viewed four differently coloured packages (regular vs. healthier; differing in brightness and saturation levels) with or without simultaneously tasting a either a regular or a healthier calorie-reduced drink. Results indicate main effects of package and taste and a package*taste interaction effect. Compared to healthier packages viewing regular packages enhanced activation in region implicated in inhibitory control (inferior frontal gyrus) and a reward-related region (striatum), the latter even more so as participants’ health interest increased (r = 0.43, p = 0.01). Incongruent package-taste combinations decreased activation in the orbitofrontal cortex (OFC, a region implicated in reward representation) compared to congruent combinations. Tasting the healthier compared to regular product enhanced activation in the middle and superior frontal gyrus, which are implicated in inhibitory control, as well as the striatum and OFC, suggesting a cognitively driven preference for the healthier product. In conclusion, this paper provides evidence for the conditions under which package colour and taste properties modulate neural correlates related to reward and inhibition. Individual differences in health-interest and impulsivity influence package- and taste-related neural correlates and thus underscore the importance of taking participant characteristics into account in food research.

    Diet and growth of juvenile queen conch Lobatus gigas (Gastropoda: Strombidae) in native, mixed and invasive seagrass habitats
    Boman, Erik Maitz ; Bervoets, Tadzio ; Graaf, Martin De; Dewenter, Jana ; Maitz, Anna ; Meijer Zu Schlochtern, Melanie P. ; Stapel, Johan ; Smaal, Aad C. ; Nagelkerke, Leopold A.J. - \ 2019
    Marine Ecology Progress Series 621 (2019). - ISSN 0171-8630 - p. 143 - 154.
    Caribbean - Halophila stipulacea - Invasive species - Mollusca - Stable isotope

    Juvenile queen conch are primarily associated with native seagrass such as Thalassia testudinum in large parts of their range in the Caribbean and the southern Gulf of Mexico. Here, a number of non-native seagrass species have been introduced including Halophila stipulacea, which is natural to the Red Sea and the Indo-Pacific. In the Caribbean, H. stipulacea often creates dense continuous mats with little or no sediment exposed, compared to native seagrass, which grows much less dense. We examined the diet and growth of juvenile conch in both native, mixed, and invasive seagrass beds using stable isotope analysis and an in situ growth enclosure experiment. Organic material in the sediment (i.e. benthic diatoms and particulate organic matter) was found to be the most important source of carbon and nitrogen for juvenile queen conch in all 3 habitats investigated, and there was a significantly higher probability of positive growth in the native seagrass compared to the invasive seagrass. Due to the importance of the organic material in the sediment as a source of nutrition for juvenile conch, limited access to the sediment in the invasive seagrass can potentially cause inadequate nutritional conditions to sustain high growth rates. Thus, it is likely that there is a negative effect on juvenile queen conch growth currently inhabiting invasive seagrass beds, compared to native seagrass beds, when other potential sources of nutrition are not available.

    A Medicago truncatula SWEET transporter implicated in arbuscule maintenance during arbuscular mycorrhizal symbiosis
    An, Jianyong ; Zeng, Tian ; Ji, Chuanya ; Graaf, Sanne de; Zheng, Zijun ; Xiao, Ting Ting ; Deng, Xiuxin ; Xiao, Shunyuan ; Bisseling, Ton ; Limpens, Erik ; Pan, Zhiyong - \ 2019
    New Phytologist 224 (2019)1. - ISSN 0028-646X - p. 396 - 408.
    arbuscular mycorrhiza (AM) - glucose - Medicago truncatula - sugar export - SWEET - symbiosis

    Plants form a mutualistic symbiosis with arbuscular mycorrhizal (AM) fungi, which facilitates the acquisition of scarce minerals from the soil. In return, the host plants provide sugars and lipids to its fungal partner. However, the mechanism by which the AM fungi obtain sugars from the plant has remained elusive. In this study we investigated the role of potential SWEET family sugar exporters in AM symbiosis in Medicago truncatula. We show that M. truncatula SWEET1b transporter is strongly upregulated in arbuscule-containing cells compared to roots and localizes to the peri-arbuscular membrane, across which nutrient exchange takes place. Heterologous expression of MtSWEET1b in a yeast hexose transport mutant showed that it mainly transports glucose. Overexpression of MtSWEET1b in M. truncatula roots promoted the growth of intraradical mycelium during AM symbiosis. Surprisingly, two independent Mtsweet1b mutants, which are predicted to produce truncated protein variants impaired in glucose transport, exhibited no significant defects in AM symbiosis. However, arbuscule-specific overexpression of MtSWEET1bY57A/G58D, which are considered to act in a dominant-negative manner, resulted in enhanced collapse of arbuscules. Taken together, our results reveal a (redundant) role for MtSWEET1b in the transport of glucose across the peri-arbuscular membrane to maintain arbuscules for a healthy mutually beneficial symbiosis.

    Phylogenomic investigation of IncI1-I plasmids harboring blaCMY-2 and blaSHV-12 in salmonella enterica and Escherichia coli in multiple countries
    Castellanos, Luis Ricardo ; Graaf-Van Bloois, Linda van der; Donado-Godoy, Pilar ; Mevius, Dik J. ; Wagenaar, Jaap A. ; Hordijk, Joost ; Zomer, Aldert L. - \ 2019
    Antimicrobial Agents and Chemotherapy 63 (2019)7. - ISSN 0066-4804
    Blc - Broiler - Chicken - DeoR - IS1294 - IS26 - ISEcp1 - S. Heidelberg - Salmonella Paratyphi B var. Java - SugE - Tn1721

    The objective of this study was to elucidate the genetic and evolutionary relatedness of blaCMY-2- and blaSHV-12-carrying IncI1-I plasmids. Phylogenomic analysis based on core genome alignments and gene presence/absence was performed for different IncI1-I sequence types (STs). Most IncI1-I/ST12 and IncI1-I/ ST231 plasmids had near-identical core genomes. The data suggest that widely occurring blaCMY-2-carrying IncI1-I/ST12 plasmids originate from a common ancestor. In contrast, blaSHV-12 was inserted independently into different IncI1-I/ST231-related plasmids.

    Loss rates of honey bee colonies during winter 2017/18 in 36 countries participating in the COLOSS survey, including effects of forage sources
    Gray, Alison ; Brodschneider, Robert ; Adjlane, Noureddine ; Ballis, Alexis ; Brusbardis, Valters ; Charrière, Jean Daniel ; Chlebo, Robert ; F. Coffey, Mary ; Cornelissen, Bram ; Amaro da Costa, Cristina ; Csáki, Tamás ; Dahle, Bjørn ; Danihlík, Jiří ; Dražić, Marica Maja ; Evans, Garth ; Fedoriak, Mariia ; Forsythe, Ivan ; Graaf, Dirk de; Gregorc, Aleš ; Johannesen, Jes ; Kauko, Lassi ; Kristiansen, Preben ; Martikkala, Maritta ; Martín-Hernández, Raquel ; Medina-Flores, Carlos Aurelio ; Mutinelli, Franco ; Patalano, Solenn ; Petrov, Plamen ; Raudmets, Aivar ; Ryzhikov, Vladimir A. ; Simon-Delso, Noa ; Stevanovic, Jevrosima ; Topolska, Grazyna ; Uzunov, Aleksandar ; Vejsnaes, Flemming ; Williams, Anthony ; Zammit-Mangion, Marion ; Soroker, Victoria - \ 2019
    Journal of Apicultural Research 58 (2019)4. - ISSN 0021-8839 - p. 479 - 485.
    Apis mellifera - beekeeping - citizen science - colony winter losses - forage sources - monitoring - mortality - survey

    This short article presents loss rates of honey bee colonies over winter 2017/18 from 36 countries, including 33 in Europe, from data collected using the standardized COLOSS questionnaire. The 25,363 beekeepers supplying data passing consistency checks in total wintered 544,879 colonies, and reported 26,379 (4.8%, 95% CI 4.7–5.0%) colonies with unsolvable queen problems, 54,525 (10.0%, 95% CI 9.8–10.2%) dead colonies after winter and another 8,220 colonies (1.5%, 95% CI 1.4–1.6%) lost through natural disaster. This gave an overall loss rate of 16.4% (95% CI 16.1–16.6%) of honey bee colonies during winter 2017/18, but this varied greatly from 2.0 to 32.8% between countries. The included map shows relative risks of winter loss at regional level. The analysis using the total data-set confirmed findings from earlier surveys that smaller beekeeping operations with at most 50 colonies suffer significantly higher losses than larger operations (p <.001). Beekeepers migrating their colonies had significantly lower losses than those not migrating (p <.001), a different finding from previous research. Evaluation of six different forage sources as potential risk factors for colony loss indicated that intensive foraging on any of five of these plant sources (Orchards, Oilseed Rape, Maize, Heather and Autumn Forage Crops) was associated with significantly higher winter losses. This finding requires further study and explanation. A table is included giving detailed results of loss rates and the impact of the tested forage sources for each country and overall.

    Diversity, abundance, distribution and habitat use of reef-associated sharks in the Dutch Caribbean : Field studies using Baited Remote Underwater Video (BRUV) and acoustic telemetry ; as part of the DCNA ‘Save Our Sharks’ project (Nationale Postcode Loterij)
    Winter, H.V. ; Graaf, M. de - \ 2019
    IJmuiden : Wageningen Marine Research (Wageningen Marine Research report C105/18) - 31
    Honey bee predisposition of resistance to ubiquitous mite infestations
    Broeckx, Bart J.G. ; Smet, Lina De; Blacquière, Tjeerd ; Maebe, Kevin ; Khalenkow, Mikalaï ; Poucke, Mario Van; Dahle, Bjorn ; Neumann, Peter ; Bach Nguyen, Kim ; Smagghe, Guy ; Deforce, Dieter ; Nieuwerburgh, Filip Van; Peelman, Luc ; Graaf, Dirk C. de - \ 2019
    Scientific Reports 9 (2019)1. - ISSN 2045-2322 - 1 p.

    Host-parasite co-evolution history is lacking when parasites switch to novel hosts. This was the case for Western honey bees (Apis mellifera) when the ectoparasitic mite, Varroa destructor, switched hosts from Eastern honey bees (Apis cerana). This mite has since become the most severe biological threat to A. mellifera worldwide. However, some A. mellifera populations are known to survive infestations, largely by suppressing mite population growth. One known mechanism is suppressed mite reproduction (SMR), but the underlying genetics are poorly understood. Here, we take advantage of haploid drones, originating from one queen from the Netherlands that developed Varroa-resistance, whole exome sequencing and elastic-net regression to identify genetic variants associated with SMR in resistant honeybees. An eight variants model predicted 88% of the phenotypes correctly and identified six risk and two protective variants. Reproducing and non-reproducing mites could not be distinguished using DNA microsatellites, which is in agreement with the hypothesis that it is not the parasite but the host that adapted itself. Our results suggest that the brood pheromone-dependent mite oogenesis is disrupted in resistant hosts. The identified genetic markers have a considerable potential to contribute to a sustainable global apiculture.

    Toll-like receptor agonists as adjuvants for inactivated porcine reproductive and respiratory syndrome virus (PRRSV) vaccine
    Vreman, Sandra ; McCaffrey, Joanne ; Popma-de Graaf, Ditta J. ; Nauwynck, Hans ; Savelkoul, Huub F.J. ; Moore, Anne ; Rebel, Johanna M.J. ; Stockhofe-Zurwieden, Norbert - \ 2019
    Veterinary Immunology and Immunopathology 212 (2019). - ISSN 0165-2427 - p. 27 - 37.
    Adjuvant - PRRSV - Skin vaccination - Toll-like receptor agonist - Vaccine

    Toll-like receptor (TLR) agonists can effectively stimulate antigen-presenting cells (APCs) and are anticipated to be promising adjuvants in combination with inactivated vaccines. In this study, the adjuvant potential of three different TLR-agonists were compared with an oil-in-water (O/W) adjuvant in combination with inactivated porcine reproductive and respiratory syndrome virus (iPRRSV) applied by different administration routes: intramuscular (i.m.) or into the skin using dissolving microneedle (DMN) patches. Pigs received a prime vaccination followed by a booster vaccination four weeks later. TLR1/2 (Pam3Cys), TLR7/8 (R848) or TLR9 (CpG ODN) agonists were used as adjuvant in combination with iPRRSV strain 07V063. O/W adjuvant (Montanide™) was used as reference control adjuvant and one group received a placebo vaccination containing diluent only. All animals received a homologous challenge with PRRSV three weeks after the booster vaccination. Antibody and IFN-γ production, serum cytokines and viremia were measured at several time-points after vaccination and/or challenge, and lung pathology at necropsy. Our results indicate that a TLR 1/2, 7/8 or 9 agonist as adjuvant with iPRRSV does not induce a detectable PRRSV-specific immune response, independent of the administration route. However, the i.m. TLR9 agonist group showed reduction of viremia upon challenge compared to the non-vaccinated animals, supported by a non-antigen-specific IFN-γ level after booster vaccination and an anamnestic antibody response after challenge. Montanide™-adjuvanted iPRRSV induced antigen-specific immunity after booster combined with reduction of vireamia. Skin application of TLR7/8 agonist, but not the other agonists, induced a local skin reaction. Further research is needed to explore the potential of TLR agonists as adjuvants for inactivated porcine vaccines with a preference for TLR9 agonists.

    In utero sFlt-1 exposure differentially affects gene expression patterns in fetal liver
    Stojanovska, V. ; Holwerda, K.M. ; Graaf, A.M. Van Der; Verkaik-Schakel, R.N. ; Boekschoten, M.V. ; Faas, M.M. ; Scherjon, S.A. ; Plösch, T. - \ 2019
    Journal of Developmental Origins of Health and Disease 10 (2019)3. - ISSN 2040-1744 - p. 353 - 361.
    animal - developmental stage - epigenetics - fetus - general - molecular/cellular - small animals

    The soluble fms-like tyrosine kinase factor 1 (sFlt-1) is a major contributor to antiangiogenesis during preeclampsia. However, little is known about the effects of sFlt-1 on fetal health. In this study we aim to evaluate the effects of the sFlt-1 concentration during pregnancy on fetal liver physiology. We used adenoviral gene delivery in Sprague-Dawley dams (seven females, 10 weeks old) during mid-gestation (gestational day 8) with adenovirus overexpressing sFlt-1, and age-matched controls (six females, 10 weeks old) with empty adenoviral virus in order to quantify the sFlt-1 concentrations in pregnant dams. Dams exposed to adenoviral sFlt-1 delivery were subdivided into a low (n=4) and high sFlt-1 (n=3) group based on host response to the virus. One-way analysis of variance showed that fetuses (five per dam) exposed to high sFlt-1 concentrations in utero show fetal growth restriction (1.84±0.043 g high sFlt-1 v. 2.32±0.036 g control; mean (M)±s.e.m.; P<0.001), without hypertension or proteinuria in the dams. In continuation, the microarray analysis of the fetal liver of the high sFlt-1 group showed significant enrichment of key genes for fatty acid metabolism and Ppara targets. In addition, using pyrosequencing, we found that the Ppara enrichment in the high sFlt-1 group is accompanied by decreased methylation of its promoter (1.89±0.097 mean % methylation in high sFlt-1 v. 2.26±0.095 mean % methylation in control, M±s.e.m., P<0.02). Our data show that high sFlt-1 concentrations during pregnancy have detrimental effects on the fatty acid metabolism genes and the Ppara targets in the fetal liver.

    Waddenstranden bezaaid met plasticdeeltjes
    Baptist, M.J. ; Ende, D. van den; Dammers, M. ; Stralen, Marnix Van - \ 2019
    A systematic review of practices to promote vegetable acceptance in the first three years of life
    Barends, Coraline ; Weenen, Hugo ; Warren, Janet ; Hetherington, Marion M. ; Graaf, Cees de; Vries, Jeanne H.M. de - \ 2019
    Appetite 137 (2019). - ISSN 0195-6663 - p. 174 - 197.
    Infants - Introducing vegetables - Systematic review - Toddlers - Vegetable intake

    Background: Although most children do not meet vegetable intake recommendations no clear universal guidelines exist on the best method of introducing and promoting vegetables in infants. Objective: To identify strategies to promote vegetable acceptance in children from the start of complementary feeding until 3 years of age. Design: A comprehensive search strategy was performed using the databases Scopus and Pubmed. Articles published before March 2018 measuring vegetable intake and/or liking were included. Results: 46 papers, 25 experimental (intervention) studies, and 21 observational studies were included. Intervention studies revealed that repeated exposure increased acceptance of the target vegetable, whereas exposure to variety was found to be particularly effective in increasing acceptance of a new vegetable. Starting complementary feeding with vegetables increased vegetable acceptance, whereas starting with fruits did not. Visual exposure to an unfamiliar vegetable increased the acceptance of that vegetable even without consuming it, while visual exposure to a familiar vegetable did not. A stepwise introduction of vegetables resulted in better initial acceptance of vegetables than introducing vegetables directly. Observational studies showed that vegetable consumption was associated with frequency of exposure, exposure to variety, and modelling. A majority of studies found a positive association between breastfeeding and vegetable acceptance, but only two out of seven studies found an association between age of vegetable introduction and their acceptance. Conclusions: Based on the papers reviewed, we conclude that introducing vegetables at the beginning of complementary feeding, giving a different type of vegetable every day and ensuring repeated exposure to the same vegetable following an interval of a few days are the most promising strategies to promote vegetable intake in children starting complementary feeding until they are 3 years of age.

    Effect of adding hop aroma in beer analysed by temporal dominance of sensations and emotions coupled with temporal liking
    Silva, Ana Patricia ; Voss, Hans Peter ; Zyl, Hannelize van; Hogg, Tim ; Graaf, Cees de; Pintado, Manuela ; Jager, Gerry - \ 2019
    Food Quality and Preference 75 (2019). - ISSN 0950-3293 - p. 54 - 63.
    Individual sensory properties of food and beverages are not perceived independently during consumption and their interaction will determine what consumers perceive and prefer. Many dynamic processes are involved in flavour release during the consumption experience and therefore its perception should be measured dynamically. To investigate how dynamic sensory and emotion profiles interact and how this relates to temporal liking, this study used a multi-sip approach with temporal dominance of sensations (TDS), temporal dominance of emotions (TDE) and temporal liking (TL), to compare three beers with small sensory differences in hop aroma: control beer (0% hop aroma), low_c beer (0.08% hop aroma) and high_c beer (0.16% hop aroma). Seventy-one beer consumers consumed a glass of each beer while performing TDE + TL and TDS + TL, on consecutive days in a sensory lab. Adding different concentrations of hop aroma in beer resulted in different dynamic sensory profiles without a difference in liking. The attribute floral was dominant in the high_c beer and in the last stage of consumption. TDE revealed an improvement of the emotional profile of the high_c beer at the beginning of consumption: three positive emotions, relaxed, pleased and happy were dominant, whereas for the other beers, one positive and one negative emotion were dominant, relaxed or pleased and disappointed. Overall differences between beers based on total duration of dominance were clear when looking at sensations rather than emotions while the combination of dynamic profiles of sensations and emotions showed a slight discrimination between the beers. It can be concluded that the subtle changes in the aroma resulted in differences in temporal dominance of sensations, did not affect liking and only slightly changed the emotion profile. The method used in this study remains to be proven further for use in food-related research and new product development, especially in the case of subtle changes.
    100 jaar Wageningen
    Heusinkveld, B.G. ; Marcelis, L.F.M. ; Kessler, C.A. ; Wamelink, G.W.W. ; Mücher, C.A. ; Vliet, A.J.H. van; Oost, J. van der; Timmermans, A.J.M. ; Wijffels, R.H. - \ 2019
    Age, gender, ethnicity and eating capability influence oral processing behaviour of liquid, semi-solid and solid foods differently
    Ketel, Eva C. ; Aguayo-Mendoza, Monica G. ; Wijk, René A. de; Graaf, Cees de; Piqueras-Fiszman, Betina ; Stieger, Markus - \ 2019
    Food Research International 119 (2019). - ISSN 0963-9969 - p. 143 - 151.
    Age - Eating capability - Ethnicity - Gender - Inter-individual variation - Oral processing

    Food oral processing depends on food properties and consumer characteristics. The aim of this study was to determine the effect of age, gender, ethnicity and eating capability on oral processing behaviour of liquid, semi-solid and solid foods. Oral processing behaviour of 18 commercially available foods, ranging from liquids, semi-solids to solids, was compared between Dutch, Caucasian adults (18-30 yrs), Chinese, Asian adults (18-30 yrs), Dutch, Caucasian elderly (60-80 yrs), and consumers with mild swallowing problems and/or low mastication efficiency (18-80 yrs). Participants were video recorded during food consumption and six oral processing parameters extracted. Elderly consumed all foods with lower eating rates (g/s) than young adults by increasing consumption time (s). Females consumed solid foods with lower eating rates (g/s) than males by reducing bite size (g). Chinese, Asian consumers consumed liquid and solid foods with lower eating rates (g/s) than Dutch, Caucasian consumers by reducing bites size (g). Chinese, Asian consumers consumed semi-solid foods with lower eating rates (g/s) than Dutch, Caucasian consumers by reducing bite size (g) and increasing consumption time (s). Consumers with decreased mastication efficiency or mild swallowing problems showed similar oral processing behaviour than healthy consumers, probably because reduction in eating capability was limited in the group. This demonstrates that different consumer groups adapt eating rate (g/s) in different ways by modifying bite size (g), consumption time (s) or both. To conclude, age, gender and ethnicity influence oral processing behaviour of liquid, semi-solid and solid foods differently. Understanding differences in oral processing behaviour of specific consumer groups can assist in steering sensory perception, food choice and energy intake of specific consumer groups such as the elderly.

    Brain Responses to Anticipation and Consumption of Beer with and without Alcohol
    Smeets, Paul A.M. ; Graaf, Cees de - \ 2019
    Chemical Senses 44 (2019)1. - ISSN 0379-864X - p. 51 - 60.

    Beer is a popular alcoholic beverage worldwide. Nonalcoholic beer (NA-beer) is increasingly marketed. Brain responses to beer and NA-beer have not been compared. It could be that the flavor of beer constitutes a conditioned stimulus associated with alcohol reward. Therefore, we investigated whether oral exposure to NA-beer with or without alcohol elicits similar brain responses in reward-related areas in a context where regular alcoholic beer is expected. Healthy men (n = 21) who were regular beer drinkers were scanned using functional MRI. Participants were exposed to word cues signaling delivery of a 10-mL sip of chilled beer or carbonated water (control) and subsequent sips of NA-beer with or without alcohol or water (control). Beer alcohol content was not signaled. The beer cue elicited less activation than the control cue in the primary visual cortex, supplementary motor area (reward-related region) and bilateral inferior frontal gyrus/frontal operculum. During tasting, there were no significant differences between the 2 beers. Taste activation after swallowing was significantly greater for alcoholic than for NA-beer in the inferior frontal gyrus/anterior insula and dorsal prefrontal cortex (superior frontal gyrus). This appears to be due to sensory stimulation by ethanol rather than reward processing. In conclusion, we found no differences in acute brain reward upon consumption of NA-beer with and without alcohol, when presented in a context where regular alcoholic beer is expected. This suggests that in regular consumers, beer flavor rather than the presence of alcohol is the main driver of the consumption experience.

    Combinations of vegetables can be more accepted than individual vegetables
    Stokkom, V.L. van; Graaf, C. de; Wang, S. ; Kooten, O. van; Stieger, M. - \ 2019
    Food Quality and Preference 72 (2019). - ISSN 0950-3293 - p. 147 - 158.
    Acceptance - Bitterness - Sweetness - Taste - Variety - Vegetables

    Enhancing sweetness of vegetables by addition of sucrose or sweeteners can increase acceptance but is not necessarily desirable. An alternative strategy could be to combine vegetables with other vegetables. By offering combinations of vegetables it might be possible to suppress bitterness, enhance sweetness and provide texture variety leading to increased acceptance. The aim of this study was to determine the influence of combining vegetables with other vegetables on sensory properties and acceptance. Carrot (sweet), cucumber (neutral), green bell pepper (bitter) and red bell pepper (sour) were assessed individually and in combination with the other three vegetables in two mixing ratios (1:2 and 2:1). Additionally, four combinations of three vegetables (mixing ratio 1:1:1) were assessed. A trained panel (n = 24) evaluated taste, flavour and texture and a consumer panel (n = 83) evaluated acceptance of all vegetables and combinations. Combining green bell pepper with carrot (1:2 and 2:1) increased sweetness and decreased bitterness. Combining cucumber, carrot or red bell pepper with green bell pepper (1:2) increased bitterness. Mainly sweetness and bitterness were associated with acceptance whereas texture (crunchiness, firmness and juiciness) did not strongly influence acceptance. Cucumber was the most accepted vegetable followed by carrot, red bell pepper and green bell pepper. Acceptance of vegetable combinations can differ from acceptance of individual vegetables depending on vegetable type and mixing ratio. Only 3 of 16 vegetable combinations had higher acceptance compared to the least accepted vegetable in the combination and similar acceptance as the more accepted vegetable in the combination. For 13 of 16 vegetable combinations acceptance did not increase compared to acceptance of individual vegetables. These findings suggest that strategies aimed at increasing vegetable consumption can be devised using specific combinations of vegetables.

    Evaluation of dietary taste patterns as assessed by FFQ against 24-h recalls and biomarkers of exposure
    Langeveld, A.W.B. van; Teo, P.S. ; Mars, M. ; Feskens, E.J.M. ; Graaf, C. de; Vries, J.H.M. de - \ 2019
    European Journal of Clinical Nutrition 73 (2019)1. - ISSN 0954-3007 - p. 132 - 140.
    Background/objective: Taste is of key importance in food choice and dietary patterns, but studies on taste profiles are limited. We previously assessed dietary taste patterns by 24 h recalls (24hR), but for epidemiological studies food frequency questionnaires (FFQ) may also be suitable. This study compared dietary taste patterns based on FFQ against 24hR and biomarkers of exposure. Subjects/methods: A taste database including 467 foods’ sweet, sour, bitter, salt, umami and fat sensation values was combined with food intake data to assess dietary taste patterns: the contribution to energy intake of 6 taste clusters. The FFQ’s reliability was assessed against 3-d 24hR and urinary biomarkers for sodium (Na) and protein intake (N) in Dutch men (n = 449) and women (n = 397) from the NQplus validation study (mean age 53 ± 11 y, BMI 26 ± 4 kg/m2). Results: Correlations of dietary taste patterns ranged from 0.39–0.68 between FFQ and 24hR (p < 0.05). Urinary Na levels, but not N levels, were positively associated with % energy intake from ‘salt, umami & fat’ tasting foods (Na; FFQ, r = 0.24, 24hR, r = 0.23, p < 0.001, N; FFQ, r = 0.08, p = 0.1394, 24hR, r = 0.05, p = 0.3427). Conclusions: The FFQ’s reliability against 24hR was acceptable to good for ranking of adults’ dietary taste patterns. Associations between dietary taste patterns and urinary Na and N were similar for FFQ and 24hR. These findings suggests that both FFQ and 24hR can be used in combination with our taste database, to investigate potential relationships between dietary taste patterns and subgroups at risk of obesity and chronic diseases such as cardiovascular disease.
    Sensory analysis of characterising flavours : Evaluating tobacco product odours using an expert panel
    Krüsemann, Erna J.Z. ; Lasschuijt, Marlou P. ; Graaf, C. de; Wijk, René A. de; Punter, Pieter H. ; Tiel, Loes van; Cremers, Johannes W.J.M. ; Nobelen, Suzanne van de; Boesveldt, Sanne ; Talhout, Reinskje - \ 2019
    Tobacco Control 28 (2019). - ISSN 0964-4563 - p. 152 - 160.
    advertising and promotion - prevention - public policy

    Objectives: Tobacco flavours are an important regulatory concept in several jurisdictions, for example in the USA, Canada and Europe. The European Tobacco Products Directive 2014/40/EU prohibits cigarettes and roll-your-own tobacco having a characterising flavour. This directive defines characterising flavour as 'a clearly noticeable smell or taste other than one of tobacco [⋯]'. To distinguish between products with and without a characterising flavour, we trained an expert panel to identify characterising flavours by smelling. Methods: An expert panel (n=18) evaluated the smell of 20 tobacco products using self-defined odour attributes, following Quantitative Descriptive Analysis. The panel was trained during 14 attribute training, consensus training and performance monitoring sessions. Products were assessed during six test sessions. Principal component analysis, hierarchical clustering (four and six clusters) and Hotelling's T-tests (95% and 99% CIs) were used to determine differences and similarities between tobacco products based on odour attributes. Results: The final attribute list contained 13 odour descriptors. Panel performance was sufficient after 14 training sessions. Products marketed as unflavoured that formed a cluster were considered reference products. A four-cluster method distinguished cherry-flavoured, vanilla-flavoured and menthol-flavoured products from reference products. Six clusters subdivided reference products into tobacco leaves, roll-your-own and commercial products. Conclusions: An expert panel was successfully trained to assess characterising odours in cigarettes and roll-your-own tobacco. This method could be applied to other product types such as e-cigarettes. Regulatory decisions on the choice of reference products and significance level are needed which directly influences the products being assessed as having a characterising odour.

    Low reported taste function is associated with low preference for high protein products in advanced oesophagogastric cancer patients undergoing palliative chemotherapy
    Vries, Y.C. de; Boesveldt, S. ; Kampman, E. ; Graaf, C. de; Winkels, R.M. ; Laarhoven, H.W.M. van - \ 2019
    Clinical Nutrition 38 (2019)1. - ISSN 0261-5614 - p. 472 - 475.
    Cancer - Chemotherapy - Food preferences - Smell - Taste
    Background & aims: Cancer patients undergoing palliative chemotherapy can experience a variety of chemosensory and food preference changes which may impact their nutritional status and quality of life. However, evidence of these changes in oesophagogastric cancer (OGC) patients is currently mostly qualitative and not supported by quantitative data. The aim of this study was to assess how self-reported and objective taste and smell function and food preferences change over time during chemotherapy in OGC patients. Methods: This observational study included 15 advanced OGC patients planned for first line treatment with capecitabine and oxaliplatin. Participants completed two test sessions scheduled before start of cytotoxic treatment and after two cycles. Self-reported and objective taste and smell function and the macronutrient and taste preference ranking task were conducted at each test session. Results: Self-reported taste and smell did not change upon chemotherapy. Objective taste function decreased during chemotherapy, although this was not statistically significant (p = 0.06), objective smell function did not change. Before and during chemotherapy, high protein foods were preferred over high carbohydrate and over low energy products, but food preferences did not change over time. A lower self-reported taste function correlated with a lower preference for high-protein products (ρ = 0.526, p = 0.003). Conclusion: This study suggests that objective taste function decreases during chemotherapy in OGC patients, but not smell function. A low reported taste function was related to a lower preference for high-protein products.
    Acidothermophilic bioreduction of sulfur for the recovery of valuable metals
    Graaf, C.M. van der; Sanchez Andrea, I. ; Stams, A.J.M. - \ 2018
    sulfur reduction - thermoacidophilic mixed culture - sulfidogenesis - metal precipitation
    Men and women differ in gastric fluid retention and neural activation after consumption of carbonated beverages
    Camps, Guido ; Graaf, Kees de; Smeets, Paul A.M. - \ 2018
    The Journal of Nutrition 148 (2018)10. - ISSN 0022-3166 - p. 1976 - 1983.
    Bloating - Carbonated drinks - Cerebral blood flow - Gastric emptying - Gender - Perfusion fMRI

    Background: The most commonly consumed carbonated beverages are soda and beer. Carbon dioxide increases gastric volume, which can lead to epigastric discomfort. Women are more susceptible to this; however, correlations with neural activity and gastric distention are unknown. Objective: This study sought to determine the subjective, gastric, and neural correlates of epigastric discomfort in men and women. Methods: Thirty-four healthy, normal-weight adults [17 women; mean ± SD body mass index (BMI; kg/m2): 22.3 ± 1.9; 17 men; BMI: 22.8 ± 1.8] participated in a randomized crossover study with 2 treatments: ingestion of 500 mL beer or soda. Before and after consumption, gastric content and brain activity were measured with magnetic resonance imaging (MRI). Participants rated fullness, bloating, hunger, and nausea at baseline and at t = 0, 10, 20, and 30 min together with gastric MRI. Brain activity [cerebral blood flow (CBF)] was measured at baseline and at t = 5 and 35 min. Liquid, gas, and total gastric volume (TGV) were segmented from gastric MRI. Ratings and gastric content areas under the curve (AUCs) were tested with a mixed model with sex and drink as factors. Results: For subjective ratings, only nausea in the beer condition scored significantly greater for women (9.4-point increase; P = 0.045). Liquid stomach content was significantly greater for women (2525 mL × min increase; P = 0.019). In both men and women, the strongest correlation for bloating was with TGV (r = 0.45, P < 0.01) and for nausea was with the liquid fraction AUC (r = 0.45, P < 0.01). CBF changes did not differ between the drinks. Men showed greater CBF than women in the left precentral and postcentral gyri at t = 5 min. Conclusions: There are differences between sexes when it comes to appetite ratings, gastric fluid retention, and neural activation. Discomfort in women may be related to fluid rather than gas in the stomach, because they retain more fluid than men. Differences between men and women should be considered when studying digestion.

    FEM Growth and Yield Data - Tropical Lowland Rainforest – Suriname Mapane
    Graaf, N.R. de; Jonkers, W.B.J. ; Jansen, J.J. ; Bongers, F. ; Sterck, F.J. ; Stuiver, B.M. ; Wirjosentono, J. ; Mohren, G.M.J. - \ 2018
    Wageningen University & Research
    growth and yield - uneven-aged mixed species forest - tropical lowland rainforest - tree diameter - tree height - cleaning - CELOS Silvicultural System
    In 23 experimental plots of 1.0 ha in Mapane Suriname 570 subplots of 0.04 ha were laid out and 7980 trees were monitored between 1981 and 1997 with different grades of intermediate tending (cleaning) as treatment.
    Heineken Green Circles
    Steingröver, E.G. - \ 2018
    In: Circular is going Global / Graaf, de, Diana, Den Haag : Netherlands Enterprise Agency - p. 26 - 27.
    1662: Koffie, wereldhandel en de consumptie-revolutie
    Zwart, P. de - \ 2018
    In: Wereldgeschiedenis van Nederland / 't Hart, M., Davids, K., Fatah-Black, K., Heerma van Voss, L., Lucassen, L., Touwen, J., Amsterdam : - ISBN 9789026343995 - p. 275 - 280.
    In Wereldgeschiedenis van Nederland vertellen meer dan honderd aanstormende en gevestigde Nederlandse onderzoekers op het gebied van geschiedenis en cultuur het wereldwijde verhaal van onze geschiedenis, onder wie Martine Gosselink, Beatrice de Graaf, Lotte Jensen, Gert Oostindie, Lodewijk Petram en Suze Zijlstra. In dit verhelderende en prikkelende boek laten zij zien hoe Nederland de wereld door de eeuwen heen mede heeft vormgegeven, en andersom: hoe Nederland zich onder invloed van verre en nabije buren heeft ontwikkeld. Van de vondst van oermens Krijn in de Noordzee tot orkaan Irma op Sint Maarten en van Bonifatius tot Pim Fortuyn – aan de hand van talloze grote en kleine historische ontwikkelingen en gebeurtenissen laat Wereldgeschiedenis van Nederland zien hoezeer Nederland verbonden is met de wereld, en de wereld met Nederland. Wereldgeschiedenis van Nederland is een uitgave van het Huygens Instituut voor Nederlandse Geschiedenis, een knaw-onderzoeksinstituut op het gebied van geschiedenis en literatuur.

    Redactie: Karel Davids, Karwan Fatah-Black, Marjolein ’t Hart, Leo Lucassen en Jeroen Touwen. Hoofdredactie: Lex Heerma van Voss
    Elke processtap telt
    Berg, C. van den - \ 2018
    Zintuigen nagebootst
    Jongsma, M.A. - \ 2018

    Wageningse onderzoekers ontwikkelen een techniek om met smaak- en geurreceptoren onze reactie op voedingsstoffen te meten.

    ‘Met proteomics en metabolomics kun je in een tomaat wel honderden verbindingen identificeren, maar dat zegt niets over de smaakfunctie. Door de grote hoeveelheid variabelen is het bijna een onoplosbare puzzel.’

    Vegetable acceptance: a bittersweet story : Role of taste in acceptance of vegetables
    Stokkom, Vera L. van - \ 2018
    Wageningen University. Promotor(en): Graaf; M. Stieger, co-promotor(en): O. van Kooten. - Wageningen : Wageningen University - ISBN 9789463433761 - 183

    Vegetable consumption is below recommended intakes in many countries, while the consumption of an adequate amount of vegetables is essential for health. Taste, especially bitter taste, is often suggested as the main cause of low vegetable acceptance. In her dissertation, Vera van Stokkom showed that the intensity of sweetness, sourness, saltiness, bitterness and umami of commonly consumed vegetables is low and that taste plays only a minor role in the identification of vegetables. Enhancing sweetness increased acceptance in both children and adults and combining vegetables compared to individual vegetables can increase acceptance as well. However, vegetable acceptance was still not very high. Mainly sweetness and bitterness were involved in vegetable acceptance, thus taste is important even though intensities are low. The results highlight the difficulty of increasing acceptance of vegetables.

    Genomic characterization of extended-spectrum cephalosporin-resistant Salmonella enterica in the Colombian poultry chain
    Castellanos, Luis Ricardo ; Graaf-van Bloois, Linda van der; Donado-Godoy, Pilar ; León, Maribel ; Clavijo, Viviana ; Arévalo, Alejandra ; Bernal, Johan F. ; Mevius, Dik J. ; Wagenaar, Jaap A. ; Zomer, Aldert ; Hordijk, Joost - \ 2018
    Frontiers in Microbiology 9 (2018)OCT. - ISSN 1664-302X
    Chicken - Latin America - MLST - pMLST - S. Heidelberg - S. Java - S. paratyphi B d-tartrate positive

    Salmonella enterica serovars have been isolated from Colombian broilers and broiler meat. The aim of this study was to investigate the diversity of ESBL/pAmpC genes in extended-spectrum cephalosporin resistant Salmonella enterica and the phylogeny of ESBL/pAmpC-carrying Salmonella using Whole Genome Sequencing (WGS). A total of 260 cefotaxime resistant Salmonella isolates, obtained between 2008 and 2013 from broiler farms, slaughterhouses and retail, were included. Isolates were screened by PCR for ESBL/pAmpC genes. Gene and plasmid subtyping and strain Multi Locus Sequence Typing was performed in silico for a selection of fully sequenced isolates. Coregenome-based analyses were performed per ST encountered. blaCMY-2-like was carried in 168 isolates, 52 carried blaCTX-M-2 group, 7 blaSHV, 5 a combination of blaCMY-2-like-blaSHV and 3 a combination of blaCMY-2-likeblaCTX-M-2 group. In 25 isolates no ESBL/pAmpC genes that were screened for were found. WGS characterization of 36 selected strains showed plasmid-encoded blaCMY-2 in 21, blaCTX-M-165 in 11 and blaSHV-12 in 7 strains. These genes were mostly carried on IncI1/ST12, IncQ1, and IncI1/ST231 plasmids, respectively. Finally, 17 strains belonged to S. Heidelberg ST15, 16 to S. Paratyphi B variant Java ST28, 1 to S. Enteritidis ST11, 1 to S. Kentucky ST152 and 1 to S. Albany ST292. Phylogenetic comparisons with publicly available genomes showed separate clustering of Colombian S. Heidelberg and S. Paratyphi B var. Java. In conclusion, resistance to extended-spectrum cephalosporins in Salmonella from Colombian poultry is mainly encoded by blaCMY-2 and blaCTX-M-165 genes. These genes are mostly associated with IncI1/ST12 and IncQ1 plasmids, respectively. Evolutionary divergence is observed between Colombian S. Heidelberg and S. Paratyphi B var. Java and those from other countries..

    Saba bank fisheries: reasons for cautions optimism
    Debrot, A.O. ; Graaf, M. de - \ 2018
    Wageningen Marine Research (WMR Policy brief ) - 5 p.
    Temporal dominance of sensations, emotions, and temporal liking measured in a bar for two similar wines using a multi-sip approach
    Silva, Ana P. ; Voss, Hans Peter ; Zyl, Hannelize van; Hogg, Tim ; Graaf, Cees de; Pintado, Manuela ; Jager, Gerry - \ 2018
    Journal of Sensory Studies 33 (2018)5. - ISSN 0887-8250

    Eating and drinking are dynamic processes where both sensations and emotions might evolve or change over time during multiple bites/sips. However, most previous studies have measured food-evoked emotions statically, that is, at a fixed time point after consumption and using a single bite/sip approach. This study aimed to explore the sensitivity of temporal dominance of sensations (TDS), of emotions (TDE), and temporal liking (TL), using a multi-sip approach, to differentiate between two comparable tasting wines. A glass of wine, in an appropriate consumption context, a bar, was served to 69 consumers, in two different sessions. It was shown that TDS and TDE captured small differences between equally liked wines. Wines were distinguishable during consumption, based on the dominance of basic sensations such as acid, bitter, and dry, rather than aromatic sensations and based on three emotions pleased, comforted, and relaxed. These emotions were dominant in both wines and in all stages of consumption but differed in the dominance rates. So, the impact of wine consumption on emotions was more uniform during consumption while new sensations became dominant during drinking. Practical implications: The method tested in this study showed a sensitivity level sufficient to capture subtle but significant differences between similar, equally liked wines. Wines tested have a major difference in wine-making process, that is, one of the wines had a particular wood aging processing in new oak barrels conferring specific flavors and associated costs. For the wine industry, the method can be particularly useful to understand to which extent consumers perceive differences in sensations and emotions, in a blind tasting, to investigate if increased costs of production are acceptable and justified. For other food products, the method can be useful to use during product development stage, when the aim is to differentiate prototypes with subtle differences in ingredients composition and associated costs. Knowing when certain sensations and emotions occur during consumption might help to create successful products in the market. Further research using different food or beverages is however necessary to assure its validity.

    Sweetness but not sourness enhancement increases acceptance of cucumber and green capsicum purees in children
    Stokkom, V.L. van; Poelman, A.A.M. ; Graaf, C. de; Kooten, O. van; Stieger, M. - \ 2018
    Appetite 131 (2018). - ISSN 0195-6663 - p. 100 - 107.
    Acceptance - Children - Sourness - Sweetness - Taste - Vegetables

    For children it is important to consume enough vegetables to establish healthy dietary patterns. Taste acceptance is an important factor contributing to food choice and consumption. Sweetness and sourness enhancement can increase acceptance of specific foods in children. The aim of this study was to determine the effect of sweetness and sourness enhancement on acceptance of cucumber and green capsicum purees in 5-6-year-old children. Three concentrations of sucrose (2, 5 and 10%) and citric acid (0.05, 0.08 and 0.15%) were added to cucumber and green capsicum purees. Children (n = 70, 5.7 ± 0.5 yrs) assessed acceptance of the vegetable purees using a 5-point hedonic facial scale. Sweetness enhancement significantly increased acceptance of cucumber purees (5 and 10% sucrose) and green capsicum purees (2 and 10% sucrose) compared to unmodified purees. Sourness enhancement (0.05, 0.08 and 0.15% citric acid) did not significantly influence acceptance of cucumber and green capsicum purees compared to unmodified purees. Children differed in acceptance of vegetable purees with added sucrose and citric acid. Sweetness likers (cucumber 77.1%, green capsicum 58.6%) accepted sucrose concentrations better than sweetness non-likers in both vegetables. Sourness likers (cucumber 50.0%, green capsicum 44.3%) accepted medium and high concentrations of citric acid better than sourness non-likers in cucumber and all citric acid concentrations in green capsicum. We conclude that enhancement of sweetness increases acceptance of cucumber and green capsicum purees in most children whereas enhancement of sourness is better accepted by only a few children. This study highlights the challenge to get children to better accept vegetables, since only sweetness enhancement improved acceptance while addition of sucrose is undesirable. For a small subset of children enhancing sourness might be an alternative strategy to increase acceptance of vegetables.

    Effect of Taste Enhancement on Consumer Acceptance of Pureed Cucumber and Green Capsicum
    Stokkom, Vera L. van; Graaf, Cees de; Kooten, Olaf van; Stieger, Markus - \ 2018
    Journal of Food Science 83 (2018)10. - ISSN 0022-1147 - p. 2578 - 2585.
    acceptance - capsicum - cucumber - taste - vegetable

    Abstract: Vegetables have low taste intensities, which might contribute to low acceptance. The aim of this study was to investigate the effect of taste (sweetness, sourness, bitterness, umami, and saltiness) and fattiness enhancement on consumer acceptance of cucumber and green capsicum purees. Three concentrations of sugar, citric acid, caffeine, mono-sodium glutamate, NaCl, and sunflower oil were added to pureed cucumber and green capsicum. Subjects (n = 66, 35.6 ± 17.7 y) rated taste and fattiness intensity. Different subjects (n = 100, 33.2 ± 16.5 years) evaluated acceptance of all pureed vegetables. Taste intensities of vegetable purees were significantly different (P < 0.05) between the three tastant concentrations except for umami in both vegetable purees, sourness in green capsicum puree, and fattiness in cucumber puree. Only enhancement of sweetness significantly (P < 0.05) increased acceptance of both vegetable purees compared to unmodified purees. In cucumber purees, relatively small amounts of added sucrose (2%) increased acceptance already significantly, whereas in green capsicum acceptance increased significantly only with addition of 5% sucrose. Enhancement of other taste modalities did not significantly increase acceptance of both vegetable purees. Enhancing saltiness and bitterness significantly decreased acceptance of both vegetable purees. We conclude that the effect of taste enhancement on acceptance of vegetable purees differs between tastants and depends on tastant concentration and vegetable type. With the exception of sweetness, taste enhancement of taste modalities such as sourness, bitterness, umami, and saltiness was insufficient to increase acceptance of vegetable purees. We suggest that more complex taste, flavor, or texture modifications are required to enhance acceptance of vegetables. Practical Application: Results can be used by cultivators to select and grow vegetable varieties with enhanced taste and flavor. Especially for cucumber, relatively small sweetness enhancement is sufficient to increase acceptance.

    Modulation of event-related potentials to food cues upon sensory-specific satiety
    Zoon, Harriët F.A. ; Ohla, Kathrin ; Graaf, Cees de; Boesveldt, Sanne - \ 2018
    Physiology and Behavior 196 (2018). - ISSN 0031-9384 - p. 126 - 134.
    Electro-encephalography - Food anticipation - Food consumption - Neural response - Olfactory - Visual

    Tempting environmental food cues and metabolic signals are important factors in appetite regulation. Food intake reduces liking of food cues that are congruent to the food eaten (sensory-specific satiety). With this study we aimed to assess effects of sensory-specific satiety on neural processing (perceptual and evaluative) of visual and olfactory food cues. Twenty healthy female subjects (age: 20 ± 2 years; BMI: 22 ± 2 kg/m2) participated in two separate test sessions during which they consumed an ad libitum amount of a sweet or savoury meal. Before and after consumption, event-related potentials were recorded in response to visual and olfactory cues signalling high-energy sweet, high-energy savoury, low-energy sweet and low-energy savoury food and non-food items. In general, we observed that food intake led to event-related potentials with an increased negative and decreased positive amplitudes for food, but also non-food cues. Changes were most pronounced in response to high-energy sweet food pictures after a sweet meal, and occurred in early processes of perception (~80–150 ms) and later processes of cognitive evaluation (~300–700 ms). Food intake appears to lead to general changes in neural processing that are related to motivated attention, and sensory-specific changes that reflect decreased positive valence of the stimuli and/or modulation of top-down cognitive control over processing of cues congruent to the food eaten to satiety.

    Colouring perception : emphasising attractiveness through packaging
    Tijssen, Irene Odilia Jelly Marcelle - \ 2018
    Wageningen University. Promotor(en): K. de Graaf, co-promotor(en): G. Jager; E.H. Zandstra. - Wageningen : Wageningen University - ISBN 9789463434836 - 148

    Healthier foods are often less tasty, less preferred and less rewarding compared to their regular counterparts. Although the principle basis of food preference is the attractiveness of flavour, other factors (e.g., package colour) are also important contributors to product perception and preference. Healthier foods are often packaged differently compared to regular products (i.e., less vibrantly coloured vs. more vibrantly coloured respectively).

    In her dissertation Irene Tijssen looked at the effects of several package colour aspects on the perception of the healthier products themselves. She found that packaging healthier foods in warmer, more saturated package colours (i.e., more vibrantly coloured) may render them more flavourful, more attractive and more rewarding. This could lead to an increase in preference for healthier foods, without changing the actual product itself. She demonstrates the abilities of package colour properties to make healthier foods more attractive and demonstrates importance of package colour aspects when designing healthier products.

    An approach to assessing the quality of birth centres results of the Dutch birth centre study
    Boesveld, Inge C. ; Hermus, Marieke A.A. ; Velden-Bollemaat, Eline C. van der; Hitzert, Marit ; Graaf, Hanneke J. de; Franx, Arie ; Wiegers, Therese A. - \ 2018
    Midwifery 66 (2018). - ISSN 0266-6138 - p. 36 - 48.
    Birth centres - Quality - Quality indicators - Structure and process assessment

    Objective: to determine the usability of a recently developed set of 30 structure and process birth centre quality indicators. Design: an explorative study using mixed-methods including literature, a survey, interviews and observations. The study is part of the Dutch Birth Centre Study. We first determined the measurability of birth centre quality indicators by describing them in detail. Next, we assessed the birth centres in the Netherlands according to these indicators using data derived from the Dutch Birth Centre General Questionnaire, the Dutch Birth Centre Integration Questionnaire, interviews, and policy documents. Setting and participants: representatives of 23 birth centres in the Netherlands. Measurements and findings: 28 of the 30 quality indicators could be used to assess birth centres in the Netherlands, one had no optimal value defined, another could not be scored because the information was not available. Each quality indicator could be scored 0 or 1. Differences between birth centres were shown: the scores ranged from 7 to 22. Some of the quality indicators can be combined or made more specific so that they are easier to assess. Some quality indicators need adaptation because they are only applicable for some birth centres (e.g. only for freestanding or alongside birth centres). Key conclusions and implications for practice: 28 of the 30 quality indicators are usable to assess structure and process quality of birth centres. With the findings of this study the set of structure and process quality indicators for birth centres in the Netherlands can be reduced to 22 indicators. This set of quality indicators can contribute to the development of a quality system for birth centres. Further research is necessary to formulate standards or minimum quality requirements for birth centres and to improve the set of birth centre quality indicators.

    Matters of taste : Dietary taste patterns in the Netherlands
    Langeveld, Astrid W.B. van - \ 2018
    Wageningen University. Promotor(en): K. de Graaf, co-promotor(en): M. Mars; J.H.M. de Vries. - Wageningen : Wageningen University - ISBN 9789463432979 - 230

    The prevalence of overweight and obesity has increased dramatically worldwide over the last decades, regardless of geographical boundaries and cultural differences. Making the desirable and appropriate food choices is important in preventing weight gain and obesity. Food choices are to a great extent guided by the taste of food.

    The overall aim of this thesis was to assess the role of taste in energy intake in young children and adults, and to investigate how taste relates to nutrients and adherence to dietary recommendations.

    In Chapter 2 we studied the relationship between taste intensity, energy and nutrient content in individual foods. We found associations between sweetness and mono- and disaccharide content, and between saltiness and sodium, protein, and fat content. Saltiness, but not sweetness, was associated with energy content. We found no modifying effect of food form, i.e. liquids, semi-solids and solids, on the relationship between taste intensity and nutrient content.

    In Chapters 3-6 we combined our taste database with dietary intake data to investigate dietary taste patterns. First, we evaluated dietary taste patterns based on FFQ against 3-d 24hR and biomarkers of exposure in an adult study population (Chapter 3). We found that the FFQ’s reliability against 24hR was acceptable to good for ranking of adults’ dietary taste patterns. Moreover, associations between dietary taste patterns and urinary Na and N were similar for FFQ and 24hR. These findings suggest that both FFQ and 24hR can be used to investigate dietary taste patterns.

    In Chapter 4 we investigated the development of dietary taste patterns during early childhood in a large population-based cohort. In children aged one year the majority of energy intake was obtained from ‘neutral’ (64%) tasting foods, which was substantially higher than in children aged two years (42%). Energy intake from ‘sweet & fat’, ‘fat’ and ‘salt, umami & fat’ tasting foods was higher in two year olds than in one year olds. Higher child BMI Z-scores were associated with relatively more energy from ‘salt, umami & fat’ tasting foods. Furthermore, higher maternal educational level was associated with relatively more energy from ‘neutral’ tasting foods and less from ‘sweet & fat’, ‘ fat’ and ‘ salt, umami & fat’ tasting foods.

    Subsequently, dietary taste patterns were investigated in adults in two study populations (Chapter 5). In both study populations we found that men consumed relatively more energy from ‘salt, umami & fat’ and ‘bitter’ tasting foods, whereas women consumed relatively more energy from ‘sweet & fat’ and ‘sweet & sour’ tasting foods. In addition, we found that obese individuals consumed relatively more energy from ‘salt, umami & fat’ tasting foods and relatively less from ‘sweet & fat’ tasting foods than lean individuals.

    In our last study, we compared dietary taste patterns of healthy and popular dietary scenarios with Dutch dietary taste patterns in women from the DNFCS 2007-2010 (Chapter 6). In addition, we investigated associations between the extent of adherence to food-based dietary guidelines, as a measure of diet quality, and dietary taste patterns in these women. We found that healthy diets may be lower in taste intensity compared with current Dutch dietary taste patterns in women. Popular diets, such as a Paleo diet, were more similar in taste intensity to the current diet.

    Diets lower in sugar, salt, and saturated fat content may be lower in taste intensity and this could be a key explanatory factor for poor adherence to dietary guidelines. However, healthy diets can be made more appealing by adding flavour, such as herbs & spices. One of the strategies that may be used to lower dietary salt, sugar and saturated fat intake is the gradual reduction of these nutrients in food. Another promising but challenging strategy could be that foods are reformulated to reduce levels of salt, sugar and saturated fat without affecting taste and palatability. However, successful application of these techniques requires substantial research and development for each product individually.

    Studying dietary intake from a taste perspective has provided new insights that may give new input for the development of randomized controlled trials. These trials are needed to investigate whether high or low sweet and salty taste exposure affects long-term perceived intensity and preferences for sweetness and saltiness and dietary taste patterns. Given the current dietary guidelines to reduce dietary salt, sugar and saturated fat intake, further research on the feasibility of these guidelines, from a taste perspective, is clearly needed.

    Altered neural responsivity to food cues in relation to food preferences, but not appetite-related hormone concentrations after RYGB-surgery
    Zoon, Harriët F.A. ; Bruijn, Suzanne E.M. de; Smeets, Paul A.M. ; Graaf, Cees de; Janssen, Ignace M.C. ; Schijns, Wendy ; Aarts, Edo O. ; Jager, Gerry ; Boesveldt, Sanne - \ 2018
    Behavioural Brain Research 353 (2018). - ISSN 0166-4328 - p. 194 - 202.
    Endocannabinoid - Energy-density - fMRI - Food cues - Ghrelin - Obesity - Olfactory - Reward - Roux-en-Y gastric bypass surgery - Visual

    Background: After Roux-en-Y gastric bypass (RYGB) surgery, patients report a shift in food preferences away from high-energy foods. Objective: We aimed to elucidate the potential mechanisms underlying this shift in food preferences by assessing changes in neural responses to food pictures and odors before and after RYGB. Additionally, we investigated whether altered neural responsivity was associated with changes in plasma endocannabinoid and ghrelin concentrations. Design: 19 RYGB patients (4 men; age 41 ± 10 years; BMI 41 ± 1 kg/m2 before; BMI 36 ± 1 kg/m2 after) participated in this study. Before and two months after RYGB surgery, they rated their food preferences using the Macronutrient and Taste Preference Ranking Task and BOLD fMRI responses towards pictures and odors of high-, and low-energy foods and non-food items were measured. Blood samples were taken to determine plasma endocannabinoid and ghrelin concentrations pre- and post-surgery. Results: Patients demonstrated a shift in food preferences away from high-fat/sweet and towards low-energy/savory food products, which correlated with decreased superior parietal lobule responsivity to high-energy food odor and a reduced difference in precuneus responsivity to high-energy versus low-energy food pictures. In the anteroventral prefrontal cortex (superior frontal gyrus) the difference in deactivation towards high-energy versus non-food odors reduced. The precuneus was less deactivated in response to all cues. Plasma concentrations of anandamide were higher after surgery, while plasma concentrations of other endocannabinoids and ghrelin did not change. Alterations in appetite-related hormone concentrations did not correlate with changes in neural responsivity. Conclusions: RYGB leads to changed responsivity of the frontoparietal control network that orchestrates top-down control to high-energy food compared to low-energy food and non-food cues, rather than in reward related brain regions, in a satiated state. Together with correlations with the shift in food preference from high- to low-energy foods this indicates a possible role in new food preference formation.

    Ons dagelijks (afval)water
    Temmink, B.G. - \ 2018
    In: Afvalwater / van Loosdrecht, Mark, Stams, Alfons, Hoekstra, Wiel, van de Graaf, Astrid, Den Haag : Stichting BWM - ISBN 9789073196902 - p. 23 - 28.
    Altered neural inhibition responses to food cues after Roux-en-Y Gastric Bypass
    Zoon, H.F.A. ; Bruijn, S.E.M. de; Jager, G. ; Smeets, P.A.M. ; Graaf, C. de; Janssen, I.M.C. ; Schijns, W. ; Deden, L. ; Boesveldt, S. - \ 2018
    Biological Psychology 137 (2018). - ISSN 0301-0511 - p. 34 - 41.
    Bariatric surgery - fMRI - Food preferences - go/no-go - Impulsivity - Inhibitory control - Weight-Loss

    Background: Roux-en-Y gastric bypass (RYGB) surgery is a highly effective weight-loss intervention that often reduces preference and intake of high-energy foods. Research into the neural mechanisms behind this shift has mainly focused on reward processing of food cues. However, the ability to successfully control food intake and thereby weight-loss also depends on inhibitory control capacity. We investigated whether RYGB leads to alterations in neural inhibitory control in response to food cues. Methods: A food-specific go/no-go task with pictures of high-energy (desserts) and low-energy foods (vegetables), was used to assess neural inhibition responses before and after RYGB with functional magnetic resonance imaging. Data from 18 morbidly obese patients (15 females; age 41 ± 11 years; BMI 42 ± 4 kg/m2 before; BMI 36 ± 4 kg/m2 after) were analysed. Pre- and post-RYGB BOLD fMRI responses were compared for response inhibition towards high- and low-energy foods. Participants were tested in a satiated state. Results: Response inhibition to high-energy foods was associated with increased activation of the right lateral prefrontal cortex (PFC), right medial PFC, dorsolateral PFC, right middle cingulate cortex and the right inferior frontal operculum (involved in inhibitory control), after compared to before surgery. Response inhibition to low-energy foods elicited diminished post- compared to pre-surgery responses in the left superior temporal pole, right parahippocampal gyrus and right hypothalamus (involved in metabolic control). Conclusion: Neural changes indicate improved response inhibition towards high-energy food cues, altered influence of metabolic control during response inhibition towards low-energy food cues and a more positive attitude to both high-energy and low-energy food after RYGB. Alterations in neural circuits involved in inhibitory control, satiety signalling and reward processing may contribute to effective weight-loss after RYGB.

    Exacting responses: lack of endocrine cephalic phase responses upon oro-sensory exposure
    Lasschuijt, Marlou P. ; Mars, Monica ; Graaf, Cees de; Smeets, Paul A.M. - \ 2018
    Frontiers in Endocrinology 9 (2018). - ISSN 1664-2392
    Ghrelin - Insulin - Pancreatic polypeptide - Taste - Texture
    Oro-sensory exposure (OSE) to food plays an important role in the regulation of food intake. One proposed underlying mechanism is the occurrence of cephalic phase responses (CPRs). CPRs include the pre-digestive endocrine responses induced by food-related sensory input. Yet, whether OSE duration or sweetness intensity affects CPRs is unknown. The objective of this study was to determine the independent and interactive effects of oro-sensory duration (chewing) and stimulation intensity (sweetness) on endocrine CPRs and satiation. Eighteen males (22 ± 2 years, BMI 22 ± 2 kg/m2) participated in a 2 × 2 randomized study with a control condition. Each session participants performed modified sham feeding (MSF) with one of the four gel-based model foods. During the control session no MSF was performed. Model foods differed in chewing duration (hard or soft texture) and sweetness (low or high intensity). During each session, eight blood samples were collected up till 25 min after MSF onset. Subsequently, food intake from an ad libitum lunch was measured. No typical CPR was found for insulin, pancreatic polypeptide (PP), and ghrelin. However, the overall PP response was 1.1 times greater for the hard sweet MSF condition compared to control (p = 0.02). Overall ghrelin responses were 1.1 times greater for the hard model food compared to the soft model food conditions (p = 0.003). These differences in endocrine response were not associated with differences in food intake at the subsequent meal. Exploratory sub-analysis of the responsive insulin curves showed that after 2.5 min of MSF the hard texture model foods insulin concentrations were 1.2 greater compared to the soft texture. These findings indicate that texture hardness and sweetness increase the overall PP response and that MSF on hard texture increases the overall ghrelin response compared to soft texture model foods. However, MSF on model foods does not lead to a typical CPR. This study, among others, shows that there are major dissimilarities in the endocrine responses to food stimulation between individuals. This emphasizes the importance of considering cephalic responders and non-responders. More research is needed to understand CPRs in relation to food texture and taste properties.
    A workshop on 'Dietary Sweetness-Is It an Issue?'
    Wittekind, Anna ; Higgins, Kelly ; McGale, Lauren ; Schwartz, Camille ; Stamataki, Nikoleta S. ; Beauchamp, Gary K. ; Bonnema, Angela ; Dussort, Pierre ; Gibson, Sigrid ; Graaf, Cees de; Halford, Jason C.G. ; Marsaux, Cyril F.M. ; Mattes, Richard D. ; McLaughlin, John ; Mela, David J. ; Nicklaus, Sophie ; Rogers, Peter J. ; Macdonald, Ian A. - \ 2018
    International Journal of Obesity 42 (2018)4. - ISSN 0307-0565 - p. 934 - 938.
    This report summarises a workshop convened by ILSI Europe on 3 and 4 April 2017 to discuss the issue of dietary sweetness. The objectives were to understand the roles of sweetness in the diet, establish whether exposure to sweetness affects diet quality and energy intake, and consider whether sweetness per se affects health. Although there may be evidence for tracking of intake of some sweet components of the diet through childhood, evidence for tracking of whole diet sweetness, or through other stages of maturity are lacking. The evidence to date does not support adverse effects of sweetness on diet quality or energy intake, except where sweet food choices increase intake of free sugars. There is some evidence for improvements in diet quality and reduced energy intake where sweetness without calories replaces sweetness with calories. There is a need to understand the physiological and metabolic relevance of sweet taste receptors on the tongue, in the gut and elsewhere in the body, as well as possible differentiation in the effects of sustained consumption of individual sweeteners. Despite a plethora of studies, there is no consistent evidence for an association of sweetness sensitivity/preference with obesity or type 2 diabetes. A multifaceted integrated approach, characterising nutritive and sensory aspects of the whole diet or dietary patterns, may be more valuable in providing contextual insight. The outcomes of the workshop could be used as a scientific basis to inform the expert community and create more useful dialogue among health care professionals.
    Homologous recombination between genetically divergent campylobacter fetus lineages supports host-associated speciation
    Gilbert, Maarten J. ; Duim, Birgitta ; Graaf-van Bloois, Linda van der; Wagenaar, Jaap A. ; Zomer, Aldert L. - \ 2018
    Genome Biology and Evolution 10 (2018)3. - ISSN 1759-6653 - p. 716 - 722.
    Campylobacter fetus - Homologous recombination - Host association - Reptile - Speciation - Whole genome sequencing

    Homologous recombination is a major driver of bacterial speciation. Genetic divergence and host association are important factors influencing homologous recombination. Here, we study these factors for Campylobacter fetus, which shows a distinct intraspecific host dichotomy. Campylobacter fetus subspecies fetus (Cff) and venerealis are associated with mammals, whereas C. fetus subsp. testudinum (Cft) is associated with reptiles. Recombination between these genetically divergent C. fetus lineages is extremely rare. Previously it was impossible to show whether this barrier to recombination was determined by the differential host preferences, by the genetic divergence between both lineages or by other factors influencing recombination, such as restriction-modification, CRISPR/Cas, and transformation systems. Fortuitously, a distinct C. fetus lineage (ST69) was found, which was highly related to mammal-associated C. fetus, yet isolated from a chelonian. The whole genome sequences of two C. fetus ST69 isolates were compared with those of mammal- and reptile-associated C. fetus strains for phylogenetic and recombination analysis. In total, 5.1-5.5% of the core genome of both ST69 isolates showed signs of recombination. Of the predicted recombination regions, 80.4% were most closely related to Cft, 14.3% to Cff, and 5.6% to C. iguaniorum. Recombination from C. fetus ST69 to Cft was also detected, but to a lesser extent and only in chelonian-associated Cft strains. This study shows that despite substantial genetic divergence no absolute barrier to homologous recombination exists between two distinct C. fetus lineages when occurring in the same host type, which provides valuable insights in bacterial speciation and evolution.

    Just add water : Effects of added gastric distention by water on gastric emptying and satiety related brain activity
    Camps, Guido ; Veit, Ralf ; Mars, Monica ; Graaf, Cees de; Smeets, Paul A.M. - \ 2018
    Appetite 127 (2018). - ISSN 0195-6663 - p. 195 - 202.
    Distention - Fullness - Gastric distention - Gastric emptying - Gastric MRI - Perfusion MRI
    Background: Gastric distention contributes to meal termination. There is little research on the neural correlates of gastric distention by food. To date, neural measures have not been obtained concurrently with measurements of gastric distention. Objectives: 1) To study how offering a small versus a large water load following a standardized nutrient load affects gastric distention over time. 2) To assess associations between satiety experiences and brain activity and the degree of gastric distention. Method: 19 healthy males (age 22.2 ± 2.5 y, BMI 21.8 ± 1.5 kg/m2) participated in a randomized crossover study with two treatments: ingestion of a 500-kcal 150-mL liquid meal shake followed by a low (LV, 50 mL) or a high volume (HV, 350 mL) water load. At baseline and three times after ingestion satiety was scored, MRI scans were made to determine total gastric content volume (TGV) and functional MRI scans were made to measure cerebral blood flow (CBF). Results: TGV was significantly higher for HV compared to LV at all time points (p < 0.001) with relative differences between HV and LV of 292 ± 37 mL after ingestion, 182 ± 83 mL at t = 15 min and 62 ± 57 mL at t = 35 min. Hunger decreased (p = 0.023) and fullness increased (p = 0.030) significantly more for HV compared to LV. Ingestion increased CBF in the inferior frontal gyrus and the anterior insula, but there were no differences between treatments. There were no significant correlations between appetite ratings and CBF values. Conclusion: Performing concurrent gastric MRI and CBF measurements can be used to investigate neural correlates of gastric distention. Increased distention did not induce significantly greater brain activation. Future research should further examine the role of the inferior frontal gyrus in satiety.
    Dietary taste patterns by sex and weight status in the Netherlands
    Langeveld, A.W.B. van; Teo, P.S. ; Vries, J.H.M. de; Feskens, E.J.M. ; Graaf, C. de; Mars, M. - \ 2018
    The British journal of nutrition 119 (2018)10. - ISSN 0007-1145 - p. 1195 - 1206.
    Taste is a key driver of food choice and intake. Taste preferences are widely studied, unlike the diet’s taste profile. This study assessed dietary taste patterns in the Netherlands by sex, BMI, age and education. A taste database, containing 476 foods’ taste values, was combined with 2-d 24-h recalls in two study populations. The percentage of energy intake from six taste clusters was assessed in the Dutch National Food Consumption Survey (DNFCS 2007–2010; n 1351) and in an independent observational study: the Nutrition Questionnaires plus (NQplus) study (2011–2013; n 944). Dietary taste patterns were similar across study populations. Men consumed relatively more energy from ‘salt, umami and fat’ (DNFCS; 24 % energy, NQplus study; 23 %)- and ‘bitter’ (7 %)-tasting foods compared with women (21 %, P<0·001, 22 %, P=0·005; 3 %, P<0·001, 4 %, P<0·001, respectively). Women consumed more % energy from ‘sweet and fat’ (15 %)- and ‘sweet and sour’ (13 %, 12 %, respectively)-tasting foods compared with men (12 %, P<0·001, 13 %, P=0·001; 10 %, P<0·001). Obese individuals consumed more % energy from ‘salt, umami and fat’- and less from ‘sweet and fat’-tasting foods than normal-weight individuals (‘salt, umami and fat’, men; obese both studies 26 %, normal-weight DNFCS 23 %, P=0·037, NQplus 22 %, P=0·001, women; obese 23 %, 24 %, normal weight 20 %, P=0·004, P=0·011, respectively, ‘sweet and fat’, men; obese 11 %, 10 %, normal weight 13 %, P<0·05, 14 %, P<0·01, women; obese 14 %, 15 %, normal weight 16 %, P=0·12, P=0·99). In conclusion, our taste database can be used to deepen our understanding of the role of taste in dietary intake in the Netherlands by sex, BMI, age and education.
    The Ozone Monitoring Instrument : Overview of 14 years in space
    Levelt, Pieternel F. ; Joiner, Joanna ; Tamminen, Johanna ; Veefkind, J.P. ; Bhartia, Pawan K. ; Zweers, Deborah C.S. ; Duncan, Bryan N. ; Streets, David G. ; Eskes, Henk ; Der, Ronald A. Van; McLinden, Chris ; Fioletov, Vitali ; Carn, Simon ; Laat, Jos De; Deland, Matthew ; Marchenko, Sergey ; McPeters, Richard ; Ziemke, Jerald ; Fu, Dejian ; Liu, Xiong ; Pickering, Kenneth ; Apituley, Arnoud ; Abad, Gonzalo González ; Arola, Antti ; Boersma, Folkert ; Miller, Christopher Chan ; Chance, Kelly ; Graaf, Martin De; Hakkarainen, Janne ; Hassinen, Seppo ; Ialongo, Iolanda ; Kleipool, Quintus ; Krotkov, Nickolay ; Li, Can ; Lamsal, Lok ; Newman, Paul ; Nowlan, Caroline ; Suleiman, Raid ; Tilstra, Lieuwe Gijsbert ; Torres, Omar ; Wang, Huiqun ; Wargan, Krzysztof - \ 2018
    Atmospheric Chemistry and Physics 18 (2018)8. - ISSN 1680-7316 - p. 5699 - 5745.
    This overview paper highlights the successes of the Ozone Monitoring Instrument (OMI) on board the Aura satellite spanning a period of nearly 14 years. Data from OMI has been used in a wide range of applications and research resulting in many new findings. Due to its unprecedented spatial resolution, in combination with daily global coverage, OMI plays a unique role in measuring trace gases important for the ozone layer, air quality, and climate change. With the operational very fast delivery (VFD; direct readout) and near real-time (NRT) availability of the data, OMI also plays an important role in the development of operational services in the atmospheric chemistry domain.
    Naar een integraal systeem voor productverbetering in Nederland : Advies van de Commissie Criteria Productverbetering
    Wilson-van den Hooven, E.C. ; Visschers, R. ; Kok, P.M.T. de; Graaf, C. de; Roodenburg, A.J.C. ; Wolvers, D. ; Berg, M. van den - \ 2018
    Bilthoven : Rijksinstituut voor Volksgezondheid en Milieu (RIVM briefrapport 2018-0056) - 56
    When “Stamppot” meets “Nasi lemak” : Dietary taste patterns in the Netherlands and Malaysia
    Teo, Pey Sze - \ 2018
    Wageningen University. Promotor(en): C. de Graaf, co-promotor(en): M. Mars; S.W. Yan. - Wageningen : Wageningen University - ISBN 9789463437608 - 224

    In recent years, dietary changes appear to be shifting universally towards a diet with high intakes of caloric sweeteners, foods from animal origin and edible oils. There is an enormous societal pressure in both middle and high income countries in the world to reduce salt, sugar and fat levels in foods. However, attempts to reduce these levels face the challenge of keeping sensory perceptions of tastes at optimal levels. From this perspective it is important to have insight in the relationships between the physical, chemical or nutrient composition of commonly consumed foods and the sensory perception of taste. In addition, the taste characteristics in current diet-within and across cultures- are highly relevant for nutritional research. Nevertheless, this demands for accurately described food-taste databases, which are supported with data on the reliability and performance of the sensory panel that determined the taste values.

    The present thesis has two main objectives. First, to quantify taste of commonly consumed foods by means of a trained sensory panel that acquired a common frame of references throughout training. Followed by to describe and compare the dietary patterns of two target populations, i.e. Dutch and Malaysian in terms of the quantified taste food database.

    In order to quantify the taste profiles of commonly consumed foods, we set-up and trained a Dutch and Malaysian taste panel, based on taste modalities of sweetness, sourness, bitterness, umami, saltiness and fat sensation, with the aid of inspired SpectrumTM scales (Chapter 2). Performance of both panels was described by discrimination, repeatability (RMSE), and agreement. Our descriptive training procedure yielded two panels from different cultures that were similar in panel performance. More importantly, they obtained similar taste profiles for 19 different foods. This implies that food-taste databases obtained with valid and standardized training procedures may be used to quantify the sensory profiles of dietary patterns of populations.

    In Chapter 3, we first compiled and translated the obtained taste profiles of a total of 892 commonly consumed foods (i.e. representing 83% and 88% of daily Dutch and Malaysian individual’s average daily energy intake) into Dutch and Malaysian taste databases. We then further combined with compositional data to investigate whether taste could function as a nutrient sensor in the context of the current diet, within and across populations. Results showed that sweetness was associated with mono- and disaccharides, umami was associated protein content, saltiness was associated with sodium content, and fat sensation was associated with fat content, in both commonly consumed Dutch and Malaysian foods. This suggests that sweetness, umami, saltiness and fat sensation can signal the presence of nutrients, and that associations of taste intensity and nutrient content are not culture-specific.

    Combined with food consumption data, the taste databases can be used to describe the taste exposures in the whole diet, i.e. dietary taste patterns. In Chapter 4, we first described the dietary taste patterns in Malaysia, and compared to these to the dietary taste patterns in The Netherlands, a country with Western eating patterns. Next to this, we further compared dietary taste patterns of specific demographic subgroups in Dutch and Malaysians, that is men and women, younger and older individuals, and overweight and normal-weight individuals. Our findings indicated that the overall dietary taste patterns were different between two populations, in which Malaysians consumed a larger percentage of energy from ‘savory fatty’ tasting foods but a smaller percentage of energy from ‘neutral’ tasting foods than Dutch. Despite these differences, men consume more savory fatty foods than women in both populations. No consistent differences were seen according to age and weight status.

    In Chapter 5, we described and compared the taste dietary patterns in the Netherlands and Malaysia, based on different eating occasions at both the level of energy contribution as well as the frequency of consumption. In total eating occasions, Malaysian individuals heightened energy intakes from ‘savory fatty’ tasting foods than ‘sweet fatty’ tasting foods compared to their Dutch counterparts. We also observed that the dietary taste patterns of main meals and snacking behaviors in the Dutch population were more varied and distinct over a day, compared to the Malaysian population. This suggests that cultural context plays an important role in determining food choice and intake patterns, even when the available foods have similar taste profiles.

    Summarizing, the research described in this thesis provides new insights by putting sensory science (i.e. perception of taste) into nutrition and public health domain. The findings showed the standardized training procedure yields similar panel performance of two cross-cultural trained taste panels, and whereby this serves as the ground work to obtain food taste profiles that can be further translated into populations’ taste databases. The information richness of the quantified food taste databases allows it to cross-correlate with compositional and consumption data, within and across cultures. The results demonstrate that taste can signal the presence of nutrients, and that associations of taste intensity and nutrient content are not culture-specific. Whilst, the overall dietary taste patterns are different across cultures, in which Malaysians heightened energy intakes from ‘savory fatty’ tasting foods than ‘sweet fatty’ tasting foods compared to Dutch. Interestingly, men consume more ‘savory fatty’ foods than women in both populations. Across eating occasions, dietary taste intake patterns of the Dutch population are more varied and distinct over a day, compared to the Malaysian population.

    In conclusion, assessing the role of taste in diet faces numerous challenges that extend beyond the rigorous measures to quantify taste and appropriateness to describe the dietary behavior as a whole diet. This thesis highlights the use of objective panel, taste databases and dietary patterns to describe and compare the taste characteristics of a diet within and across cultures. By focusing on the role of taste in diet, we learned that cultural context plays an important role in determining food choice and intake, even when the available foods have similar taste characteristics. Much more needs to be done not only in expanding and updating food taste databases; there is also a need to further assess the dietary taste patterns in other population groups, i.e. children, elderly, patients and ethnic-specific groups. Future prospective studies should be carried-out to relate the dietary taste patterns with chronic diseases. Studying dietary patterns from a taste perspective - and not only a nutritional perspective – can provide us with a deeper understanding of the role of taste in dietary intake.

    Modelling the recruitment of European eel (Anguilla anguilla) throughout its European range
    Bornarel, Virginie ; Lambert, Patrick ; Antunes, Carlos ; Belpaire, Claude ; Ciccotti, Eleonora ; Diaz, Estibaliz ; Diserud, Ola ; Doherty, Denis ; Domingos, Isabel ; Evans, Derek ; Graaf, Martin De; O'Leary, Ciara ; Pedersen, Michael ; Poole, Russell ; Walker, Alan ; Wickström, Håkan ; Beaulaton, Laurent ; Drouineau, Hilaire - \ 2018
    ICES Journal of Marine Science 75 (2018)2. - ISSN 1054-3139 - p. 541 - 552.
    GEREM - glass eel - panmixia - temperate eel - trend
    European eel (Anguilla anguilla) recruitment has been declining at least since the early 1980s at the scale of its distribution area. Since the population is panmictic, its stock assessment should be carried out on a range-wide basis. However, assessing the overall stock during the continental phase remains difficult given its widespread distribution among heterogeneous and separate river catchments. Hence, it is currently considered by the International Council for the Exploration of the Sea (ICES) more feasible to use glass eel recruitment data to assess the status of the overall population. In this study, we used Glass Eel Recruitment Estimation Model (GEREM) to estimate annual recruitment (i) at the river catchment level, a scale for which data are available, (ii) at an intermediate scale (6 European regions), and (iii) at a larger scale (Europe). This study provides an estimate of the glass eel recruitment trend through a single index, which gathers all recruitment time-series available at the European scale. Results confirmed an overall recruitment decline to dramatically low levels in 2009 (3.5% of the 1960-1979 recruitment average) and highlighted a more pronounced decline in the North Sea area compared to elsewhere in Europe.
    Taste and smell perception and quality of life during and after systemic therapy for breast cancer
    Vries, Y.C. de; Boesveldt, S. ; Kelfkens, C.S. ; Posthuma, E.E. ; Den Berg, M.M.G.A. van; Kruif, J.T.C.M. de; Haringhuizen, A. ; Sommeijer, D.W. ; Buist, N. ; Grosfeld, S. ; Graaf, C. de; Laarhoven, H.W.M. van; Kampman, E. ; Winkels, R.M. - \ 2018
    Breast Cancer Research and Treatment 170 (2018)1. - ISSN 0167-6806 - p. 27 - 34.
    Breast cancer - Chemotherapy - Dysgeusia - Herceptin - Quality of life - Smell - Taste - Taste loss - Trastuzumab
    Purpose: The purpose of the study was to assess self-reported taste and smell perception after chemotherapy in breast cancer patients compared with women without cancer, and to assess whether taste and smell perception is associated with quality of life after the end of chemotherapy. Methods: We included 135 newly diagnosed breast cancer patients who completed chemotherapy and 114 women without cancer. Questionnaires on taste, smell, and quality of life were completed shortly after and 6 months after chemotherapy (patients) or at two moments with 6 months’ time window in between (comparisons). Results: Self-reported taste and smell perception were significantly lower in patients shortly after chemotherapy compared to the comparison group. Most patients recovered 6 months after chemotherapy, although patients who were still receiving trastuzumab then reported a lower taste and smell perception compared to patients who were not. A lower self-reported taste and smell were statistically significantly associated with a worse quality of life, social, emotional, and role functioning shortly after chemotherapy. Six months after chemotherapy, taste and smell were statistically significantly associated with quality of life, social and role functioning, but only in patients receiving trastuzumab. Conclusions: Most taste and smell alterations recovered within 6 months after the end of chemotherapy for breast cancer, but not for patients receiving trastuzumab. These results highlight the importance of monitoring taste and smell alterations during and after treatment with chemotherapy and trastuzumab, as they may impact quality of life.
    Severity of olfactory deficits is reflected in functional brain networks-An fMRI study
    Reichert, Johanna L. ; Postma, Elbrich M. ; Smeets, Paul A.M. ; Boek, Wilbert M. ; Graaf, Kees de; Schöpf, Veronika ; Boesveldt, Sanne - \ 2018
    Human Brain Mapping 39 (2018)8. - ISSN 1065-9471 - p. 3166 - 3177.
    Anosmia - FMRI - Functional connectivity - Hyposmia - Neuronal plasticity - Olfaction - Olfactory disorders
    Even though deficits in olfactory function affect a considerable part of the population, the neuronal basis of olfactory deficits remains scarcely investigated. To achieve a better understanding of how smell loss affects neural activation patterns and functional networks, we set out to investigate patients with olfactory dysfunction using functional magnetic resonance imaging (fMRI) and olfactory stimulation. We used patients' scores on a standardized olfactory test as continuous measure of olfactory function. 48 patients (mean olfactory threshold discrimination identification (TDI) score=16.33, SD=6.4, range 6 - 28.5) were investigated. Overall, patients showed piriform cortex activation during odor stimulation compared to pure sniffing. Group independent component analysis indicated that the recruitment of three networks during odor stimulation was correlated with olfactory function: a sensory processing network (including regions such as insula, thalamus and piriform cortex), a cerebellar network and an occipital network. Interestingly, recruitment of these networks during pure sniffing was related to olfactory function as well. Our results support previous findings that sniffing alone can activate olfactory regions. Extending this, we found that the severity of olfactory deficits is related to the extent to which neural networks are recruited both during olfactory stimulation and pure sniffing. This indicates that olfactory deficits are not only reflected in changes in specific olfactory areas but also in the recruitment of occipital and cerebellar networks. These findings pave the way for future investigations on whether characteristics of these networks might be of use for the prediction of disease prognosis or of treatment success.
    Slow down! : exploring opportunites for reducing eating rate
    Boer, J. van den - \ 2018
    Wageningen University. Promotor(en): K. de Graaf, co-promotor(en): M. Mars. - Wageningen : Wageningen University - ISBN 9789463432542 - 190

    The obesity epidemic demonstrates that people are having difficulties with limiting energy intake to match energy expenditure. Therefore strategies to make controlling energy intake easier and more enjoyable need to be identified. Research suggests that lowering eating rate, i.e. the amount of food consumed per unit of time (g/min), could be an effective strategy. Lowering eating rate is expected to facilitate the control of long-term energy intake and body weight by increasing satiety.

    Eating rate can be targeted by means of different approaches. It, however, is still unclear what would be an effective approach for lowering long-term eating rate, and whether it would be successful at lowering long-term energy intake and body weight. Hence, the current thesis investigated several opportunities for lowering eating rate and explored their potential to lower energy intake and body weight. Different approaches were considered:

    1. Targeting the person: i.e. to change habitual eating rate (Chapter 2 and 3)

    2. Targeting the food: i.e. to select foods that take more time to consume (Chapter 4 and 5)

    3. Targeting the eating environment: i.e. to make changes to the direct eating environment of a person (Chapter 6)

    In Chapter 2 it was investigated whether eating rate is a stable personal characteristic that is associated with energy intake and BMI using data from the NQplus-cohort. The results confirm that eating rate is highly dependent on the individual and is relatively constant within an individual. Moreover, the analyses show that being a fast eater is associated with a higher long-term energy intake and BMI in the Dutch population.

    In Chapter 3 the acceptability of the ‘eating detection sensor’ (i.e. a new electronic device that can potentially be used to retrain a person’s eating rate) was investigated by means of 4 evaluation studies. The results show that people are open to the idea of using such devices for monitoring and retraining eating behavior. These devices, however, need to be comfortable to wear and discreet.

    In Chapter 4 the eating rate of the most commonly consumed foods (i.e. how fast they can be consumed, g/min) was investigated. Moreover, it was investigated what the energy intake rate (i.e. the eating rate of a food multiplied by the energy density of a food, kcal/min) of these foods is. Energy intake rate is expected to be a stronger predictor of energy intake than eating rate or energy density as such. The eating rate of 240 foods—representing the whole Dutch diet—was measured in a laboratory setting. The results showed a wide variation in eating rate (range: 2-641 g/min) and energy intake rate (range: 0-422 kcal/min), both within and between food groups. This demonstrates that the foods consumed provide opportunities for selecting alternatives with a lower eating rate and energy intake rate.

    In Chapter 5 it was investigated to what extent Dutch adults are consuming foods with a low and high energy intake rate (kcal/min), and whether this is associated with their energy intake and BMI. The dataset described in Chapter 4 was merged with 24h-recall data from the Dutch National Food Consumption Survey to enable these analyses. The results show that the consumption pattern of Dutch adults provide opportunities for lowering energy intake rate. The energy intake rate of the diet was found to be positively associated with long-term energy intake, but not with BMI.

    Finally, Chapter 6 describes an experiment that tested whether a person’s bite frequency (i.e. number of bites per minute), and therefore eating rate, is affected by the bite frequency of an eating companion, and whether this has an effect on food intake. It was found that a person’s bite frequency is unaffected by the bite frequency of an eating companion.

    Summarizing, the research described in this thesis provides new insights into the opportunities for lowering long-term eating rate, and thereby long-term energy intake and body weight. The results show that lowering a person’s eating rate may result in a lower long-term energy intake and BMI, and that technological solutions could be used to lower a person’s eating rate. Furthermore, the results demonstrate that Dutch adults have ample possibilities to shift their diets towards foods with a lower eating rate, and that it could be a promising strategy for lowering long-term energy intake. We found no evidence that eating rate can be lowered through changes in the direct eating environment.

    To conclude, the results of this thesis provide input for the development of randomized controlled trials. These are needed to confirm whether there is a causal relation between eating rate, long-term energy intake and weight status. It is important that the potential of eating rate is further investigated, as lowering eating rate is expected to make people feel full on fewer calories and thereby make controlling energy intake easier and more enjoyable.

    Sweet taste exposure and the subsequent acceptance and preference for sweet taste in the diet : Systematic review of the published literature
    Appleton, Km ; Tuorila, H. ; Bertenshaw, Ej ; Graaf, C. De; Mela, Dj - \ 2018
    American Journal of Clinical Nutrition 107 (2018)3. - ISSN 0002-9165 - p. 405 - 419.
    exposure - food choice - food intake - food preferences - sweet taste
    Background There are consistent, evidence-based global public health recommendations to reduce intakes of free sugars. However, the corresponding evidence for recommending reduced exposure to sweetness is less clear. Objective Our aim was to identify and review the published evidence investigating the impact of dietary exposure to sweet-tasting foods or beverages on the subsequent generalized acceptance, preference, or choice of sweet foods and beverages in the diet. Design Systematic searches were conducted to identify all studies testing relations of variation in exposure to sweetness through foods and beverages with subsequent variation in the generalized acceptance, preference, or choice of sweetened foods or beverages, in humans aged >6 mo. Results Twenty-one studies met our inclusion criteria, comprising 7 population cohort studies involving 2320 children and 14 controlled trials involving 1113 individuals. These studies were heterogeneous in study design, population, exposure, and outcomes measured, and few were explicitly designed to address our research question. The findings from these were inconsistent. We found equivocal evidence from population cohort studies. The evidence from controlled studies suggests that a higher sweet taste exposure tends to lead to reduced preferences for sweetness in the shorter term, but very limited effects were found in the longer term. Conclusions A small and heterogeneous body of research currently has considered the impact of varying exposure to sweet taste on subsequent generalized sweet taste preferences, and this evidence is equivocal regarding the presence and possible direction of a relation. Future work should focus on adequately powered studies with well-characterized exposures of sufficient duration. This review was registered with PROSPERO as CRD42016051840, 24 November 2016.
    The efficacy of daily snack replacement with oligofructose-enriched granola bars in overweight and obese adults : a 12-week randomised controlled trial
    Pol, Korrie ; Graaf, Cees de; Meyer, Diederick ; Mars, Monica - \ 2018
    The British journal of nutrition 119 (2018)9. - ISSN 0007-1145 - p. 1076 - 1086.
    Body composition - Dietary supplements - Food intake - Inulin-type fructan - Obesity - Oligofructose - Overweight - Satiety
    Oligofructose is a prebiotic dietary fibre obtained from chicory root inulin. Oligofructose supplementation may affect satiety, food intake, body weight and/or body composition. The aim was to examine the efficacy of oligofructose-supplemented granola bars on the following weight management outcomes: satiety, energy intake, body weight and body composition in overweight or obese adults. In all, fifty-five adults with overweight or obesity (thirty-six females/nineteen males; age: 41 (sd 12) years; 90·6 (sd 11·8) kg; BMI: 29·4 (sd 2·6) kg/m2) participated in a parallel, triple-blind, placebo-controlled intervention. A total of twenty-nine subjects replaced their snacks twice a day with an equienergetic granola bar supplemented with 8 g of oligofructose (OF-Bar). Subjects in the control group (n 26) replaced their snack with a control granola bar without added oligofructose (Co-Bar). Satiety, 24-h energy intake, body weight and body composition (fat mass and waist circumference) were measured at baseline, weeks 6 and 12. In addition, weekly appetite and gastrointestinal side effects were measured. During the intervention, energy intake, body weight and fat mass remained similar in the Co-Bar and OF-Bar groups (all P>0·05). Both groups lost 0·3 (sd 1·2) kg lean mass (P<0·01) and reduced their waist circumference with −2·2 (sd 3·6) cm (P<0·0001) after 12 weeks. The OF-Bar group reported decreased hunger in later weeks of the intervention (P=0·04), less prospective food consumption (P=0·03) and less thirst (P=0·003). To conclude, replacing daily snacks for 12 weeks with oligofructose-supplemented granola bars does not differentially affect energy intake, body weight and body composition compared with a control bar. However, there was an indication that appetite was lower after oligofructose bar consumption.
    Indirect vs direct assessment of gastric emptying : A randomized crossover trial comparing C-isotope breath analysis and MRI
    Camps, G. ; Mars, M. ; Witteman, B.J.M. ; Graaf, C. de; Smeets, P.A.M. - \ 2018
    Neurogastroenterology & Motility 30 (2018)7. - ISSN 1350-1925
    Breath - Gastric emptying - Isotope - MRI
    Background: Indirect methods to assess gastric emptying (GE), such as 13C breath tests (BT), are commonly used. However, BT usually use a sampling time of 4+ hours. The current study aims to assess the validity of BT for four liquid meals differing in physicochemical properties. To this aim, we compared them to MRI GE-measurements. Methods: Fifteen healthy males (age 22.6 ± 2.4 years, BMI 22.6 ± 1.8 kg/m2) participated in a randomized 2 × 2 crossover experiment. Test foods were liquid meals, which were either thin/thick and 100/500 kcal, labeled with 100 mg of 13C-octanoate. GE was measured with MRI and assessed by 13C recovery from breath. Participants were scanned every 10 minutes and at six time points breath samples were collected up to t = 90 minutes. Two curves were fitted to the data to estimate emptying halftime (t50 Ghoos and t50 Bluck). T50 times were ranked per participant and compared between methods. Key Results: On average, MRI and BT showed similar t50 rankings for the four liquid meals. In comparison to MRI, t50 Ghoos overestimated, while t50 Bluck underestimated GE time. Moreover, more viscous foods were overestimated. In most participants individual t50 time rankings differed significantly between methods. Conclusions & Inferences: BT can assess relative emptying differences on group level and collecting breath data for 90 minutes constitutes a lower burden for participants and the research facility. However, BT has severe shortcomings compared to MRI for individual GE assessment. Notably, food matrix effects should be considered when interpreting the results of BT.
    Similar taste-nutrient relationships in commonly consumed Dutch and Malaysian foods
    Teo, Pey Sze ; Langeveld, Astrid W.B. van; Pol, Korrie ; Siebelink, Els ; Graaf, Cees de; Yan, See Wan ; Mars, Monica - \ 2018
    Appetite 125 (2018). - ISSN 0195-6663 - p. 32 - 41.
    Commonly consumed - Cross-cultural - Foods - Nutrient content - Taste intensity
    Three recent studies showed that taste intensity signals nutrient content. However, current data reflects only the food patterns in Western societies. No study has yet been performed in Asian culture. The Malaysian cuisine represents a mixture of Malay, Chinese and Indian foods. This study aimed to investigate the associations between taste intensity and nutrient content in commonly consumed Dutch (NL) and Malaysian (MY) foods. Perceived intensities of sweetness, sourness, bitterness, umami, saltiness and fat sensation were assessed for 469 Dutch and 423 Malaysian commonly consumed foods representing about 83% and 88% of an individual's average daily energy intake in each respective country. We used a trained Dutch (n = 15) and Malaysian panel (n = 20) with quantitative sensory Spectrum™ 100-point rating scales and reference solutions, R1 (13-point), R2 (33-point) and R3 (67-point). Dutch and Malaysian foods had relatively low mean sourness and bitterness (
    Estimating and mitigating post-release mortality of European eel by combining citizen science with a catch-and-release angling experiment
    Weltersbach, Marc Simon ; Strehlow, Harry Vincent ; Ferter, Keno ; Klefoth, Thomas ; Graaf, Martin de; Dorow, Malte de; Dorow, Malte - \ 2018
    Fisheries Research 201 (2018). - ISSN 0165-7836 - p. 98 - 108.
    Anguilla anguilla - Discard mortality - Fishing gear selectivity - Hooking mortality - Recreational fisheries - Stock assessment
    Several anguillid eel species have experienced severe population declines over the past decades, particularly the European eel (Anguilla anguilla), which is listed as critically endangered by the International Union for Conservation of Nature. To reduce fishing mortality, many European countries have introduced strict recreational eel fishing regulations increasing regulatory catch-and-release (C & R) practice. Despite high release rates, only limited information exists on the potential consequences of C & R on eels. A field experiment was conducted with pre-tagged eels in a semi-natural environment to investigate lethal and sublethal impacts of C & R. The experiment was combined with a citizen science study evaluating the effects of different hooks on catch rates, fish size, and hooking location to develop best practice guidelines. Short-term mortality (≤72 h) ranged from 0.0–18.2%, and adjusted long-term mortality ( > 72 h) from 0.0–46.2% depending on treatments, resulting in adjusted total mortality rates between 8.4% and 64.4% at the end of the study period (≥43 d). The only significant predictor of mortality was the occurrence of bleeding from hooking injuries. Deep hooking was common, and only few deep-hooked eels for which the fishing line was cut and the hook left in place shed the hook after release. However, no significant effect of C & R on eel condition was found. The citizen science study showed that anglers can significantly decrease the catch of small eels, and thus release rates, by using large J-hooks. Furthermore, large J-hooks or circle hooks reduced the likelihood of deep hooking compared to small J-hooks. Post-release mortality of eels caught in recreational fisheries needs to be considered in future stock assessments and management plans to ensure conservation of the European eel. This study also highlights the strength of combining citizen science with experimental studies to develop best practice guidelines promoting fish conservation.
    Variability in size at maturity and reproductive season of queen conch Lobatus gigas (Gastropoda : Strombidae) in the Wider Caribbean Region
    Boman, Erik Maitz ; Graaf, Martin de; Nagelkerke, Leopold A.J. ; Stoner, Allan W. ; Bissada, Caroline E. ; Avila-Poveda, Omar Hernando ; Baqueiro-Cardenas, Erick Raul ; Smaal, Aad C. - \ 2018
    Fisheries Research 201 (2018). - ISSN 0165-7836 - p. 18 - 25.
    Caribbean - Fisheries management - Mollusks - Reproductive biology - Sexual dimorphism
    Queen conch (Lobatus gigas), is an economically and culturally important marine gastropod. The species is subject to extensive exploitation throughout large parts of the Caribbean which has led to a decrease in population densities across much of the species’ distribution range. Hence, there is a need for protective measures to safeguard the reproductive stock. This requires a better estimation of its size at maturity, which is best quantified as the thickness of the lip that the shell develops after reaching its maximum length. The lip thickness at 50% maturity (LT50) was determined using a logistic and an accumulation model, from seven representative location of distribution of this species in the Wider Caribbean Region. LT50 of both females (7–14 mm) and males (4–11.5 mm) varied between different locations in the Caribbean, although it did not correspond with variation in water temperature. In most cases females had a larger LT50 than males indicating sexual dimorphism. LT50 values estimated with the logistic model were smaller (7–14 mm for females, 4–11.5 mm for males) than values estimated with the accumulation model (13–26 mm for females, 16–24 mm for males), showing an overestimation of LT50 in queen conch in previous studies which used the accumulation model to estimate LT50. Locations with a relatively high variation in water temperature had a significantly shorter reproductive season. The implementation of adequate minimum size regulation based on lip thickness (ca. 15 mm) and a Caribbean wide seasonal closure (May–September) using the most recent biological information from this study, taking into consideration the local differences in LT50 and reproductive season, will assist in developing a long term sustainable queen conch fishery in the Caribbean.
    Training of a Dutch and Malaysian sensory panel to assess intensities of basic tastes and fat sensation of commonly consumed foods
    Teo, Pey Sze ; Langeveld, Astrid W.B. van; Pol, Korrie ; Siebelink, Els ; Graaf, Cees de; Martin, Christophe ; Issanchou, Sylvie ; Yan, See Wan ; Mars, Monica - \ 2018
    Food Quality and Preference 65 (2018). - ISSN 0950-3293 - p. 49 - 59.
    Cross-cultural - Panel performance - Spectrum - Taste profiling - Trained panel
    Taste has a nutrient sensing function and guides food choices. Therefore, investigating taste profiles of dietary patterns - within and across cultures - is highly relevant for nutritional research. However, this demands for accurately described food-taste databases, which are supported with data on the reliability and performance of the sensory panel that determined the taste values.This study aimed to assess the performance of a trained Dutch and Malaysian sensory panel. More importantly, we assessed whether the standardized training procedure in the two countries yielded similar taste profiles with respect to 15 basic taste solutions, and 19 foods differing in tastes.A Dutch (n = 15) and Malaysian panel (n = 20) were trained for 56-63 h, using basic taste solutions and reference foods on 6 scales, i.e. sweetness, sourness, bitterness, umami, saltiness and fat sensation. Performance of both panels was described by discrimination, repeatability (RMSE), and agreement. Nineteen products with different sensory characteristics were profiled in the Netherlands and Malaysia; subsequently the obtained taste profiles were compared.Both panels were able to discriminate between solutions and products (all p < .001). A vast majority of the taste values could be reproduced; the RMSEs of the different taste values varied between 2.3 and 13.3%. Panel agreement was achieved after the training with solutions; however not for all attributes of the reference foods. Some taste values of the 19 foods were significantly different, however most of these differences were small (<10. points).Our descriptive training procedure yielded two panels from different cultures that were similar in panel performance. More importantly, they obtained similar taste profiles for 19 different foods. This implies that food-taste databases obtained with valid and standardized training procedures may be used to quantify the sensory profiles of dietary patterns of populations.
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