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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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.

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 - \ 2018
Tobacco Control (2018). - ISSN 0964-4563
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.

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
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
University. Promotor(en): Kees de Graaf, co-promotor(en): Monica Mars. - Wageningen : Wageningen University - ISBN 9789463437608 - 224
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 (2018). - ISSN 0167-6806 - p. 1 - 8.
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 (2018). - ISSN 1065-9471
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
University. Promotor(en): Kees de Graaf, co-promotor(en): Monica Mars. - Wageningen : Wageningen University - ISBN 9789463432542 - 190
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
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 (2018). - 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 (<R1), but higher mean sweetness, saltiness and fat sensation (between R1 and R2). Mean umami taste intensity of Malaysian foods (15-point) was higher than that of Dutch foods (8-point). Positive associations were found between sweetness and mono- and disaccharides (R2 = 0.67 (NL), 0.38 (MY)), between umami and protein (R2 = 0.29 (NL), 0.26 (MY)), between saltiness and sodium (R2 = 0.48 (NL), 0.27 (MY)), and between fat sensation and fat content (R2 = 0.56 (NL), 0.17(MY)) in Dutch and Malaysian foods (all, p < 0.001). The associations between taste intensity and nutrient content are not different between different countries, except for fat sensation-fat content. The two dimensional basic taste-nutrient space, representing the variance and associations between tastes and nutrients, is similar between Dutch and Malaysian commonly consumed foods.
Estimating and mitigating post-release mortality of European eel by combining citizen science with a catch-and-release angling experiment
Weltersbach, Marc Simon ; Weltersbach, Marc Simon ; Strehlow, Harry Vincent ; Ferter, Keno ; Klefoth, Thomas ; Graaf, Martin de; Graaf, Martin 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.
Recreational sea fishing in Europe in a global context-Participation rates, fishing effort, expenditure, and implications for monitoring and assessment
Hyder, Kieran ; Weltersbach, Marc Simon ; Armstrong, Mike ; Ferter, Keno ; Townhill, Bryony ; Ahvonen, Anssi ; Arlinghaus, Robert ; Baikov, Andrei ; Bellanger, Manuel ; Birzaks, Janis ; Borch, Trude ; Cambie, Giulia ; Graaf, Martin De; Diogo, Hugo M.C. ; Dziemian, Łukasz ; Gordoa, Ana ; Grzebielec, Ryszard ; Hartill, Bruce ; Kagervall, Anders ; Kapiris, Kostas ; Karlsson, Martin ; Kleiven, Alf Ring ; Lejk, Adam M. ; Levrel, Harold ; Lovell, Sabrina ; Lyle, Jeremy ; Moilanen, Pentti ; Monkman, Graham ; Morales-Nin, Beatriz ; Mugerza, Estanis ; Martinez, Roi ; O'Reilly, Paul ; Olesen, Hans Jakob ; Papadopoulos, Anastasios ; Pita, Pablo ; Radford, Zachary ; Radtke, Krzysztof ; Roche, William ; Rocklin, Delphine ; Ruiz, Jon ; Scougal, Callum ; Silvestri, Roberto ; Skov, Christian ; Steinback, Scott ; Sundelöf, Andreas ; Svagzdys, Arvydas ; Turnbull, David ; Hammen, Tessa Van Der; Voorhees, David Van; Winsen, Frankwin Van; Verleye, Thomas ; Veiga, Pedro ; Vølstad, Jon-Helge ; Zarauz, Lucia ; Zolubas, Tomas ; Strehlow, Harry V. - \ 2018
Fish and Fisheries 19 (2018)2. - ISSN 1467-2960 - p. 225 - 243.
European marine recreational fisheries - fisheries assessment and management - fishing effort and expenditure - participation - surveys and monitoring of marine recreational fisheries
Marine recreational fishing (MRF) is a high-participation activity with large economic value and social benefits globally, and it impacts on some fish stocks. Although reporting MRF catches is a European Union legislative requirement, estimates are only available for some countries. Here, data on numbers of fishers, participation rates, days fished, expenditures, and catches of two widely targeted species were synthesized to provide European estimates of MRF and placed in the global context. Uncertainty assessment was not possible due to incomplete knowledge of error distributions; instead, a semi-quantitative bias assessment was made. There were an estimated 8.7 million European recreational sea fishers corresponding to a participation rate of 1.6%. An estimated 77.6 million days were fished, and expenditure was €5.9 billion annually. There were higher participation, numbers of fishers, days fished and expenditure in the Atlantic than the Mediterranean, but the Mediterranean estimates were generally less robust. Comparisons with other regions showed that European MRF participation rates and expenditure were in the mid-range, with higher participation in Oceania and the United States, higher expenditure in the United States, and lower participation and expenditure in South America and Africa. For both northern European sea bass (Dicentrarchus labrax, Moronidae) and western Baltic cod (Gadus morhua, Gadidae) stocks, MRF represented 27% of the total removals. This study highlights the importance of MRF and the need for bespoke, regular and statistically sound data collection to underpin European fisheries management. Solutions are proposed for future MRF data collection in Europe and other regions to support sustainable fisheries management.
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