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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    Older adults, mealtime-related emotions, and functionalities : tailoring protein-enriched meals
    Uijl, Louise C. den - \ 2016
    Wageningen University. Promotor(en): Kees de Graaf, co-promotor(en): Stefanie Kremer; Gerry Jager. - Wageningen : Wageningen University - ISBN 9789462578920 - 178
    meals - emotions - elderly nutrition - elderly - smell - food preferences - protein - proteins - questionnaires - young adults - chocolate - maaltijden - emoties - ouderenvoeding - ouderen - reuk - voedselvoorkeuren - eiwit - eiwitten - vragenlijsten - jongvolwassenen - chocolade

    Background and aim

    Dietary proteins are of special interest for the heterogeneous group of older adults, since these people do not always have an adequate protein intake. When protein-rich products are better aligned with the requirements of older persons, an adequate nutrient intake is more likely. In this thesis we therefore explored two approaches for tailoring protein-enriched meals to older consumer subgroups; emotion-based and functionality-based. We expected a better ‘product-cluster fit’ (i.e. a more positive meal experience) when the clusters’ meal associations are congruent to their mealtime expectations.


    We conducted an online survey in which vital community-dwelling older adults (n=392) reported their mealtime-related emotions and mealtime functionality. Using a hierarchical clustering analysis we described clusters within our population. Subsequently, we explored the extent to which the expectations of these clusters can be applied for the development of tailored protein-enriched meals. For the emotion-based approach, we conducted two central location tests (CLTs, n=461) to explore older adults’ food-evoked emotions. For the functionality-based approach we conducted in-depth interviews in order to get further insights regarding functional mealtime expectations and attitudes towards proteins and protein-enrichment. Based on the latter insights we tailored PE meal concepts to two functionality-based segments. In a final home-use test, the members of the functionality-based segments (n=91) prepared and evaluated the tailored PE meal concepts.


    The emotion-based approach resulted in four clusters; pleasurable averages, adventurous arousals, convivial indulgers, and indifferent restrictives. These emotions that these segments associated with their mealtimes varied along the two dimensions valence and arousal. However, from both CLTs we learned that the variation in valence-arousal as observed for mealtime-related emotions was not observed for emotions related to actual foods. The latter makes it challenging to identify products that evoke emotions congruent to the mealtime expectations of the emotion-based clusters.

    With regard to the functionality-based approach, we encountered three clusters; physical nutritioners, cosy socialisers, and thoughtless averages. The cosy socialisers value the social interactions and cosiness during their mealtimes, whereas the physical nutritioners focus more on the health and nutrient aspects of meals. Thoughtless averages have the least distinctive mealtime expectations. We translated these functional mealtime expectations into two PE meal concepts; one tailored to cosy socialisers and one tailored to physical nutritioners. These meal concepts were well-accepted by the participants. However, congruency between mealtime expectations and functional meal associations did not result in a better ‘product-cluster fit’.


    Given the challenge to identify congruency between the meal associations and the mealtime expectations of the emotion-based clusters, we consider the emotion-based approach to be not yet actionable enough as a basis for tailoring PE products to older consumers. In contrast, the functionality-based approach appeared to be more promising, since the functional meal expectations could be translated to well-accepted tailored PE meal concepts. However, the effectivity of our functionality-based approach was not yet confirmed in this thesis, since congruency between functional meal associations and functional meal expectations did not necessarily result in a better ‘product-cluster fit’. Future studies, focussing on e.g. other meal types, are recommended to further explore mealtime functionality as a basis for tailoring PE meals to older consumer subgroups.

    Dietary epicatechnin and quercetin in cardiovascular health and disease
    Dower, J.I. - \ 2016
    Wageningen University. Promotor(en): Daan Kromhout; Marianne Geleijnse, co-promotor(en): Peter Hollman. - Wageningen : Wageningen University - ISBN 9789462577862 - 164
    cardiovascular disorders - cardiovascular diseases - epicatechin - quercetin - epidemiological surveys - genome analysis - chocolate - hart- en vaatstoornissen - hart- en vaatziekten - epicatechine - quercetine - epidemiologische onderzoeken - genoomanalyse - chocolade

    Epidemiological studies showed that the consumption of flavonoid-rich foods such as cocoa and tea is associated with a lower risk of cardiovascular disease (CVD). Randomised controlled trials (RCTs) showed that cocoa and tea improved markers of cardiometabolic health including blood pressure, endothelial function, insulin resistance, arterial stiffness and inflammation.

    Cocoa is particularly rich in the flavan-3-ol epicatechin and tea is the main dietary source of epicatechin and of the major flavonol quercetin. However, evidence on the individual roles of epicatechin and quercetin in the health effects of cocoa and tea is still scarce. Therefore, we estimated the strength of the association between epicatechin intake and CVD mortality in a prospective cohort study. Furthermore, we also investigated the effects of epicatechin and quercetin on markers of cardiometabolic health and gene expression, by means of two RCTs.

    In Chapter 2, the association between epicatechin intake and CVD mortality was studied using data from the Zutphen Elderly Study, a cohort of 744 elderly Dutch men. During 25 years of follow-up, 329 men died from CVD and 148 from coronary heart disease (CHD). Results from this study showed that men in the highest tertile of epicatechin intake had a 38% lower risk of CHD mortality compared to men in the lowest tertile. For men with prevalent CVD, the risk of CVD mortality was 46% lower for men in the highest tertile of intake, compared to men in the lowest tertile. This is the first epidemiological study to have investigated the association between epicatechin intake and CVD mortality. Hence, more and larger cohort studies are required to confirm this association, possibly with a focus on populations with a high risk of CVD.

    In Chapter 3, the chronic effects of pure epicatechin and quercetin on markers of cardiometabolic health were investigated by means of a RCT. Thirty-seven apparently healthy men and women aged 40–80 years consumed (-)-epicatechin (100 mg/d), quercetin-3-glucoside (160 mg/d), or placebo capsules for 4 weeks, in random order. Markers of cardiometabolic health were measured before and after each 4-week intervention. The results of this study showed that epicatechin improved insulin resistance and had a borderline significant effect on endothelial function. This suggests that epicatechin contributes to the cardioprotective effects of cocoa and tea, however, larger long-term RCTs are required to confirm these effects. Pure quercetin supplementation did not affect any of these markers of cardiometabolic health.

    Using data from the same study, we investigated the effects of supplementation of pure epicatechin and quercetin on a comprehensive set of biomarkers of endothelial dysfunction and inflammation (Chapter 4). With the exception of sE-selectin (a biomarker of endothelial dysfunction), epicatechin supplementation did not beneficially influence any of the biomarkers, suggesting a lack of evidence for a role of epicatechin in inflammation. Quercetin also lowered sE-selectin as well as the inflammatory biomarker IL-1β and the overall z-score for inflammation. This suggests that quercetin may contribute to the cardioprotective effects of tea by reducing inflammation and possibly by improving endothelial function.

    In the same study, the effects of pure epicatechin supplementation on whole genome gene expression profiles of circulating immune cells were also assessed (Chapter 5). Pure epicatechin supplementation modestly reduced gene expression related to inflammation signalling routes in circulating immune cells – routes which are known to play a role in cardiovascular health. However, there was no evidence that epicatechin affected pathways related to insulin resistance or endothelial function.

    To directly compare the acute effects of pure epicatechin and epicatechin from dark chocolate on vascular function, we carried out an acute RCT in 20 apparently healthy men aged 40-80 years (Chapter 6). On three separate occasions, subjects consumed: 1) 70g dark chocolate (150 mg epicatechin) with two placebo capsules; 2) two pure epicatechin capsules (100 mg epicatechin) with 75g white chocolate and 3) two placebo capsules with 75g white chocolate (0 mg epicatechin). Endothelial function and arterial stiffness were measured before and two hours after each intervention. To determine epicatechin bioavailability, epicatechin metabolites were measured in blood samples taken at repeated intervals over a period of 8 hours. There was no significant difference in improvement in endothelial function or arterial stiffness between pure epicatechin and dark chocolate. There was also no difference in bioavailability of pure epicatechin and epicatechin from dark chocolate, when standardised per 100 mg of epicatechin. This suggests that epicatechin may contribute to the vascular effects of cocoa and that the bioavailability of pure epicatechin and epicatechin from dark chocolate is similar.

    In the general discussion, the main findings of this thesis were first summarised. Methodological considerations related to cohort studies, such as the assessment of flavonoid intake and the possibility of residual confounding were also discussed. Issues related to the relevance of cardiometabolic markers in RCTs and the effect of cocoa flavan-3-ol bioavailability were addressed. Finally, suggestions for future research were put forward.

    In conclusion, the results of this thesis suggest that epicatechin contributes to the cardioprotective effects of cocoa and tea. Epicatechin intake was inversely related to CHD mortality in elderly men, and to CVD mortality in men with prevalent CVD. The cardioprotective effects of epicatechin are likely mediated through improvements in insulin resistance and possibly endothelial function. In contrast, quercetin is unlikely to play a major role in the cardioprotective effects of tea. Results for quercetin from cohort studies are inconclusive, and based on the results of our chronic RCT, quercetin did not affect vascular function or insulin resistance, but may help to lower inflammation. Evidence of the role that individual flavonoids play in the aetiology of CVD is still limited. More studies with pure flavonoids are required to elucidate their role.

    Rheological behaviour of fibre-rich plant materials in fat-based food systems
    Bonarius, G.A. ; Vieira, J.B. ; Goot, A.J. van der; Bodnar, I. - \ 2014
    Food Hydrocolloids 40 (2014). - ISSN 0268-005X - p. 254 - 261.
    suspension rheology - sugar dispersions - chocolate - oils - emulsifiers - particles - sucrose - forces
    The potential use of fibre-rich materials as bulking agents to replace sucrose in chocolate confectionary products is investigated. Since the rheological behaviour of the molten chocolate mass is key in chocolate production, the rheology of fibre-rich materials in medium chain triglycerides (MCT) is studied and compared to the rheology of sucrose in MCT. The materials studied are side streams of the fruit and vegetable processing industry: lemon peels, spent grain, grape pomace and pecan fibre. All suspensions showed shear thinning behaviour at volume fractions >0.2, where side stream materials showed lower shear thinning behaviour than sucrose. The values for the maximum packing fraction, obtained via the Maron–Pierce equation and using the Casson Plastic Viscosities, were lower for the side stream materials than for sucrose. Addition of lecithin resulted in a decrease in the Casson Yield Value of sucrose suspensions, which was not observed with the fibre-rich materials. The rheological behaviour of the fibre-rich materials suspended in MCT is explained by the effective volume of the irregularly shaped particles. The behaviour of sucrose suspensions is explained by the formation of aggregates, which seem to be promoted by water bridges between the particles. Overall, the behaviour of the sucrose dispersions was very different compared to the other materials with respect to the shear thinning behaviour, the impact of lecithin as well as the impact of water. Therefore it is suggested that only partial replacement of sucrose by fibre-rich materials will be successful in industrial product development.
    Temporal dominance of emotions: Measuring dynamics of food-related emotions during consumption
    Jager, G. ; Schlich, P. ; Tijssen, I.O.J.M. ; Yao, Y.J. ; Visalli, M. ; Graaf, C. de; Stieger, M.A. - \ 2014
    Food Quality and Preference 37 (2014). - ISSN 0950-3293 - p. 87 - 99.
    time-intensity - mood - experience - perception - chocolate - profile - liking - memory
    Mapping food-evoked emotions in addition to sensory profiling is topical. In sensory profiling, the Temporal Dominance of Sensation (TDS) method focuses on the assessment of the temporal evolution of dominant sensory attributes over time. We hypothesize that food-evoked emotions also show temporal dynamics that can be related to dynamic sensory perception. This study assessed temporal dynamics of sensory and emotional attributes during chocolate tasting. We used TDS to determine dynamic sensory properties of dark chocolates providing a list of 10 sensory attributes. Comparably, Temporal Dominance of Emotions (TDE) was assessed by replacing the sensory attributes with 10 emotional attributes. Sixty-two participants assessed TDS and TDE of five commercially available dark chocolates (plain and flavoured). Multivariate comparisons (Hotelling test) showed significant differences between products based on the dominance duration of sensory (p <0.05) and emotional attributes (p <0.05). TDS difference curves revealed products to differ based on their dominant sensory attributes, with different attributes peaking at different time moments. TDE difference curves showed that products also differed in the temporal distribution of dominant emotional attributes. Comparing the average dominance rates between plain dark and flavoured dark chocolates revealed that for flavoured dark chocolates mainly flavour attributes and positive/active emotions were perceived as salient whereas for plain dark chocolates textural as well as taste attributes were dominant accompanied by more negative/non-energetic emotions. A joint CVA plot on the duration of dominance for sensory and emotional attributes per product revealed that temporal evolution of sensory – and emotional attributes was related. This suggests a mutual reciprocity between those two entities (sensory and emotional attributes) resulting in more complex, richer product characterization. In conclusion, these findings show TDE to be a promising new venue in characterising food-evoked emotions in relation to sensory profiling.
    Direct estimate of cocoa powder content in cakes by colorimetry and photoacoustic spectroscopy
    Doka, O. ; Bicanic, D.D. ; Kulcsar, R. - \ 2014
    International Journal of Thermophysics 35 (2014)12. - ISSN 0195-928X - p. 2206 - 2214.
    phenolic content - theobroma-cacao - antioxidant - quantification - polyphenols - chocolate - capacity - beans - fat
    Cocoa is a very important ingredient in the food industry and largely consumed worldwide. In this investigation, colorimetry and photoacoustic spectroscopy were used to directly assess the content of cocoa powder in cakes; both methods provided satisfactory results. The calibration curve was constructed using a series of home-made cakes containing varying amount of cocoa powder. Then, at a later stage, the same calibration curve was used to quantify the cocoa content of several commercially available cakes. For self-made cakes, the relationship between the PAS signal and the content of cocoa powder was linear while a quadratic dependence was obtained for the colorimetric index TeX (brightness) and total color difference
    High fat challenges and detection of early perturbations in endothelial health : the use of a comprehensive phenotyping approach
    Esser, D. - \ 2013
    Wageningen University. Promotor(en): Michael Muller, co-promotor(en): Lydia Afman. - S.l. : s.n. - ISBN 9789461735911 - 168
    endotheel - vetconsumptie - voedingsvet - lipidenmetabolisme - chocolade - endothelium - fat consumption - dietary fat - lipid metabolism - chocolate

    Background:Cardiovascular disease (CVD) is one of the leading causes of morbidity and mortality worldwide. One of the pathophysiology’s that play a pivotal role in the development and progression of CVD is a dysfunctional endothelium. An important lifestyle risk factor for endothelial dysfunction is the diet and several nutrients have been classified to be either beneficial or harmful for the endothelium. Although CVD usually affects middle-aged or older adults, the onset of endothelial dysfunction begins in early life, emphasising the need for primary prevention. We therefore aimed to identify markers of early perturbations in endothelial health by using dietary stressors, e.g. high fat (HF) challenge test. Thereafter we aimed to evaluate if the potential early markers are reversible and can be improved after an intervention with a dietary anti-stressor.

    Methods:First we validated the HF challenge test as a tool to trigger the endothelial response capacity. For that purpose, we compared the postprandial response after a HF shake with an average breakfast shake in young healthy men by assessing several plasma markers and functional measures of endothelial function. To identify new markers for early perturbations in endothelial health and to optimized the HF challenge test we applied three HF challenges differing in fatty acid type in two populations of middle-aged men, i.e. one at high- and one at low risk for developing CVD and characterized the postprandial response by applying high-throughput metabolomic and transcriptomic tools next to an extensive phenotyping of vascular function and vascular health parameters. Lastly, we evaluated if the, in the studies above, identified potential early biomarker profile is reversible and can be improved after an intervention with a dietary anti-stressor by means of a high flavanol chocolate intervention.

    Results:In young men, we observed that a HF challenge decreased flow mediated dilation (FMD), but this decrease was also found after the consumption of an average breakfast shake. IL-8 concentrations were more pronouncedly increased after HF shake consumption compared to an average breakfast control shake. In middle-aged men, a HF challenge decreased the augmentation index (AIX) and elicited an activated state of cellular adherence in the circulation as determined by increased plasma soluble adhesion molecules, increased leukocyte cell surface integrin and selectin expression and increased number of leukocytes. A challenge high in mono-unsaturated fatty acids (MUFAs) elicited the highest postprandial triglyceride (TG) concentrations and the most pronounced effects on AIX. By applying high-throughput metabolomic tools, we observed that oxylipin profiles were affected by the HF challenge and that these changes were depended on dietary fatty acid composition. Application of transcriptome profiling revealed that changes in peripheral blood mononuclear cell (PBMC) gene expression profiles after a HF challenge test were different between lean and obese subjects, with the most deviating effect after MUFA intake. The saturated fatty acid (SFA) shake decreased the expression of genes involved in cholesterol uptake and cholesterol biosynthesis and increased expression of genes involved in cholesterol efflux. MUFA increased expression of inflammatory genes and of peroxisome proliferator-activated receptor α (PPARα) target genes involved in β-oxidation. 4-week daily intake of a dietary anti-stressor, e.g. dark chocolate, increased fasting FMD and decreased AIX, and elicited a less activated state of cellular adherence, as determined by a decrease in plasma soluble adhesion molecules, a decrease in leukocyte cell surface integrin and selectin expression and a decrease in the number of leukocytes.

    Conclusions:In this thesis we extensively characterized the postprandial response to a HF challenge in human subjects with different disease risk profiles and optimized the HF challenge test. We identified MUFAs as most potent fatty acids to trigger the vascular and cellular response capacity, which makes it the optimal fatty acid type to use in a HF challenge test. We demonstrated that besides functional measures of vascular function, also plasma and cellular factors involved in leukocyte adhesion to the endothelium are adversely affected by dietary stressors and are beneficially affected by a dietary anti-stressor. Therefore, we conclude that endothelial health can be more comprehensively measured by means of a biomarker profile consisting not only of the vascular function measures FMD and AIX, but also of a subset of soluble adhesion molecules in the plasma, leukocyte counts and cell surface integrin and selectin expression. To identify potential new leads for biomarkers, we applied whole genome gene expression profiling, combined with the HF challenge test which enabled us to detect small differences in health status. Furthermore, we identified metabolic and inflammatory pathways that are specifically affected by either MUFAs or SFAs. These findings increased our understanding on how a SFA or MUFA challenge exert their distinct effects on stress related and metabolic compensatory cellular processes and provided us with new potential leads to detect early perturbations in endothelial health.

    Cacao, flavanolen, en hart- en vaatziekten: Stand van de wetenschap
    Buijsse, B. ; Kromhout, D. - \ 2010
    Voeding Nu 12 (2010)3. - ISSN 1389-7608 - p. 15 - 17.
    chocolade - flavanoïden - hart- en vaatziekten - hypertensie - ziektepreventie - gezondheidsvoedsel - onderzoek - voeding en gezondheid - chocolate - flavanoids - cardiovascular diseases - hypertension - disease prevention - health foods - research - nutrition and health
    De gedachte dat cacao gezondheidseffecten bezit is niet nieuw. Al in de 18e eeuw werd verondersteld dat cacao een veelvoud aan kwalen kon verlichten, alleen ontbrak hiervoor lange tijd de wetenschappelijke onderbouwing. Nadat halverwege de jaren negentig van de vorige eeuw werd ontdekt dat cacao rijk is aan flavanolen werd het een populair onderzoeksonderwerp. Vooral de effecten op hart en bloedvaten staan hierbij in de belangstelling. Wat is de stand van de wetenschap?
    De jacht op het geheim van cacao
    Hollman, P.C.H. - \ 2008
    Kennis Online 5 (2008)dec. - p. 9 - 9.
    cacao - chocolade - hart- en vaatziekten - ziektepreventie - voeding en gezondheid - cocoa - chocolate - cardiovascular diseases - disease prevention - nutrition and health
    Je kans op een dodelijke hartaanval halveert als je elke dag een groot paaseitje pure chocolade eet, blijkt uit een recente Nederlandse epidemiologische studie. En ook andere studies laten zien dat consumptie van cacao beschermt tegen hart- en vaatziekten. Maar het is nog een raadsel hoe dat precies komt, zegt Peter Hollman van RIKILT – Instituut voor voedselveiligheid. "Het menselijk lichaam neemt de bioactieve stoffen in cacao nauwelijks op"
    Tribological Properties of Neutral Polysaccharide Solutions under Simulated Oral Conditions
    Zinoviadou, K. ; Janssen, A.M. ; Jongh, H.H.J. de - \ 2008
    Journal of Food Science 73 (2008)2. - ISSN 0022-1147 - p. E88 - E94.
    lubrication - texture - hydrocolloids - chocolate - rheology - custards - behavior - contact - model - food
    Predictability of the perception of foods thickened by polysaccharides is only poor. Therefore, the effect of saliva on the lubrication properties of 2 types of neutral polysaccharides, cross-linked starch and locust bean gum, was studied. Despite the similar bulk rheological behavior of the 2 polysaccharides, the starch solution exhibited a significantly lower friction coefficient. Although starch viscosity was strongly decreased upon 10 s incubation with human saliva, a low friction coefficient was retained. The presence of remaining granules is held partly responsible for this. Addition of starch granules to locust bean gum also resulted in a decrease in the friction coefficient, but the effect was smaller compared to starch solutions digested by saliva. Smaller contact angles were measured for (digested) starch compared to locust bean gum solutions. This points to other parameters that assist in lubrication, such as the interaction of starch solution constituents with the rubbing surfaces. In addition, the importance of bulk viscosity for spreadability on surfaces was demonstrated. This study illustrates that the type of starch will determine not only the viscosity change but also the presence of intact granules upon digestion by saliva in the oral cavity; the combination of these 2 properties is regarded to be responsible for the poor predictability of sensory responses of starch containing foods.
    Direct observation of adhesion and spreading of emulsion droplets at solid surfaces
    Dresselhuis, D.M. ; Aken, G.A. van; Hoog, E.H.A. de; Cohen Stuart, M.A. - \ 2008
    Soft Matter 4 (2008). - ISSN 1744-683X - p. 1079 - 1085.
    in-water emulsions - o/w emulsions - lubrication - tribology - friction - coalescence - chocolate - membrane - tissue - layers
    Sensory perception of fat is related to orally perceived in-mouth friction. From this perspective, we investigate adhesion and spreading of emulsion droplets on solid surfaces and connect it to the ability of food emulsions to lower friction. Furthermore, we study what the contribution is of the separate colloidal forces on droplet adhesion. The effect of saliva on adhesion and spreading is also briefly investigated.Using a flow cell in combination with light microscopy and video imaging allowed us to clearly distinguish between adhered and spread emulsion droplets. The capability to make this distinction between adhesion and spreading experimentally is new and provided us with the insight that the occurrence of spreading is essential for lowering friction. Mainly electrostatic, steric and hydrophobic interactions of the droplets with solid surfaces are found to determine adhesion and subsequent spreading of emulsion droplets. This was investigated by varying the adsorbed amount of protein, the ionic strength of the emulsion as well as the hydrophobicity of the solid surface. Especially the hydrophobic interaction between droplet and surface is shown to be crucial for droplet adhesion and spreading. Saliva is of minor importance for adhesion and spreading. This work gives insight in the way emulsion droplets interact with solid surfaces and the type of colloidal interactions that play a role. The information it provides can be used to develop emulsions that are reasonably stable during the shelf life of the product, but do spread on oral surfaces, thus lowering friction and enhancing fat perception
    Fat retention at the tongue and the role of saliva: Adhesion and spreading of 'protein-poor' versus 'protein-rich' emulsion
    Dresselhuis, D.M. ; Cohen Stuart, M.A. ; Aken, G.A. van; Schipper, R.G. ; Hoog, E.H.A. de - \ 2008
    Journal of Colloid and Interface Science 321 (2008)1. - ISSN 0021-9797 - p. 21 - 29.
    mucin muc5b - tribology - mouth - stability - chocolate - component - friction - gland
    Fat perception of food emulsions has been found to relate to in-mouth friction. Previously, we have shown that friction under mouth-like conditions strongly depends on the sensitivity of protein-stabilized emulsion droplets to coalescence. Here, we investigated whether this also implies that oral fat retention depends in a similar manner on the stability of the emulsion droplets against coalescence. We investigate the separate contributions of droplet adhesion and droplet spreading to fat retention at the tongue, as well as the role of saliva. We perform ex vivo (Confocal Raman Spectroscopy; Confocal Scanning Laser Microscopy) experiments using pig's tongue surfaces in combination with human in vivo experiments. These reveal that protein-poor (unstable) emulsions are retained more at the tongue than protein-rich (stable) emulsions. Furthermore, the layer formed by adhering protein-poor droplets is more stable against rinsing. Saliva is found to be very efficient in removing fat and emulsion droplets from the oral surface but its role in fat retention needs further research. We relate our results to the colloidal forces governing droplet adhesion and spreading.
    Application of oral tissue in tribological measurements in an emulsion perception context
    Dresselhuis, D.M. ; Hoog, E.H.A. de; Cohen Stuart, M.A. ; Aken, G.A. van - \ 2008
    Food Hydrocolloids 22 (2008)2. - ISSN 0268-005X - p. 323 - 335.
    in-water emulsions - dairy-products - human tongue - lubrication - creaminess - behavior - chocolate - texture - cavity - saliva
    Tribological measurements are indicated to be a tool in predicting the creamy in-mouth sensation of a food product. Tribological measurements relating lubricational behaviour of a food product to perception are often conducted with artificial surfaces. In this work we used pig's tongue to mimic the human tongue, which has the advantage of having surface characteristics similar to a human tongue. Using biological material has also some drawbacks. The most important drawbacks are the limited availability, the individual differences between the tongues, and the relative fast degradation of the tissue. The aim of this study was to identify the characteristics of the tongue in terms of surface roughness, deformability and wetting properties. The knowledge on these characteristics can serve as reference when using modified poly dimethyl siloxane (PDMS) in tribological experiments relating perception to in-mouth friction. Furthermore, we demonstrated that these characteristics are crucial in tribological studies to draw rightful conclusions. Tribological measurements were performed with an experimental set-up combining friction measurement with confocal scanning laser microscope (CSLM) observations. We identified the importance of these characteristics for tribology measurements performed in relation to sensory perception. It is shown that the tongue surface has some very typical characteristics, including the presence of papillae and a hydrophilic mucus layer, and an elastic modulus that is at least two orders of magnitude smaller than that of smooth PDMS surfaces. The different surface characteristics appear to lead to completely different lubricational behaviour of the food emulsions between these surfaces. Furthermore, for food emulsions differences in the occurrence of coalescence were found between shearing with pig's tongue and PDMS surfaces. Therefore, we conclude that for studies relating sensory properties of food systems to lubricational behaviour, a careful choice of representative surfaces is essential and that modification of smooth PDMS can result in surfaces having characteristics closer to tongue tissue
    Tribology of o/w emulsions under mouth-like conditions: determinants of friction
    Dresselhuis, D.M. ; Klok, H.J. ; Cohen Stuart, M.A. ; Vries, R.J. de; Aken, G.A. van; Jongh, H.H.J. de - \ 2007
    Food Biophysics 2 (2007)4. - ISSN 1557-1858 - p. 158 - 171.
    in-water emulsions - lubrication mechanism - boundary lubrication - surface modification - protein adsorption - behavior - saliva - flocculation - perception - chocolate
    Fat-perception is thought to be related to a complex interplay between fat-associated flavor release and mouth-feel. Friction sensed between the tongue and the palate seems to play a prominent role: in previous work, we have shown that emulsions that are more sensitive toward coalescence give rise to a lowering of the orally perceived and experimentally measured friction and, probably as a consequence, to an enhanced fat-perception. In this paper, we study in detail the factors determining friction of protein-stabilized emulsions using a novel mouth-mimicking tribometer and model surfaces consisting of PDMS modified in various ways (hydrophobicity, deformability, roughness). We show that unlike in many technological applications where lubrication is essentially hydrodynamic, for physiologically relevant loads, the modified PDMS is boundary and/or mixed lubricated, which is like in-mouth lubrication. We find that an increased sensitivity of the emulsions toward coalescence results in a lower friction, confirming previous results obtained with pig¿s tongue. Surface-induced coalescence (or spreading of emulsion droplets) seems to be very important in this, surface hydrophobicity being the dominant trigger. Viscosity of the dispersed phase does not have such a strong influence on both the measured friction and the oral perceived friction. We do find a strong influence of the presence of bulk proteins and saliva on friction. Finally, hardly any dependence of measured friction on fat content of the emulsion was observed, indicating that only a small amount of fat is needed to alter the friction.
    Onderzoek naar de kwaliteit van chocoladerepen
    Sledsens, A.M.J. ; Herstel, H. - \ 1989
    Wageningen : RIKILT (Rapport / RIKILT 89.12) - 14
    chocolade - voedselkwaliteit - chocolate - food quality
    Om de kwaliteit van in willekeurige winkels gekochte chocoladerepen te kunnen beoordelen heeft Konsumenten Kontakt het RIKILT verzocht 24 monsters chocoladerepen te onderzoeken. Alle monsters zijn onderzocht op nettogewicht, totaal vet, vocht, saccharose, lactose, theobromine, triglyceridensamenstelling en salmonella. Alle monsters zijn ook sensorisch beoordeeld.
    Methode - ontwikkeling voor het bepalen van het gehalte aan cacaoboterequivalente vetten in chocoladeprodukten
    Kamp, H.J. van der; Muuse, B.G. - \ 1985
    Wageningen : RIKILT (Rapport / RIKILT 85.42) - 8
    cacao - chocolade - vetten - oliën - bakoliën - bakvetten - kwantitatieve analyse - spijsoliën - spijsvetten - cocoa - chocolate - fats - oils - cooking oils - cooking fats - quantitative analysis - edible oils - edible fats
    De Europese Commissie (EC) bestudeert de mogelijkheden om cacaoboteralternatieve vetten (CDA) toe te staan in chocolade tot een gehalte van 5% van de waar zonder declaratleverplichting. Voorwaarde is de controleerbaarheid met een betrouwbare analysemethode. De CAODISCO ontwikkelde een triglyceridemethode waarmee cacaoboter equivalente vetten kunnen worden bepaald. Dit verslag gaat in op de CAOBISComethode en de daarop gebaseerde EEG ringtest. Tot slot wordt het resultaat vermeld van onderzoek naar de samenstelling van Nederlandse chocolade geanalyseerd met deze CAOBISCQ-methode.
    Onderzoek naar de kwaliteit van chocoladevla en - toetjes
    Oortwijn, H. ; Herstel, H. - \ 1983
    Wageningen : RIKILT (Verslag / RIKILT 83.50) - 23
    desserts - custardpudding - chocolade - voedselsamenstelling - voedselkwaliteit - kwaliteitscontroles - monsters - desserts - custard - chocolate - food composition - food quality - quality controls - samples
    Er werden 20 monsters chocoladevla en 13 monsters chocoladetoetjes chemisch, microbiologisch en sensorisch onderzocht.
    Voederwaardeaspekten van cacaoschroot
    Steg, A. ; Rijpkema, Y.S. - \ 1975
    Hoorn : [s.n.] (Intern rapport / Instituut voor veevoedingsonderzoek Hoorn no. 81) - 30
    bijproducten - chocolade - cacao - voedselindustrie - byproducts - chocolate - cocoa - food industry
    Onderzoek naar de noodzaak van voorbehandeling van cacao - afvalkalk bij toepassing in de tuinbouw
    Boon, J. van der; Kolenbrander, G.J. ; Wiersum, L.K. - \ 1963
    Groningen : [s.n.] (Rapport / Instituut voor bodemvruchtbaarheid, Groningen 1963, no. 11) - 28
    chocolade - cacao - kunstmeststoffen - vliegas - fruitgewassen - industrieel afval - mest - plantenvoeding - vuilnis - residuen - afval - chocolate - cocoa - fertilizers - fly ash - fruit crops - industrial wastes - manures - plant nutrition - refuse - residues - wastes
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