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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Food reward from a behavioural and (neuro)physiological perspective
Bruijn, Suzanne E.M. - \ 2017
University. Promotor(en): Kees de Graaf; Renger Witkamp, co-promotor(en): Gerry Jager. - Wageningen : Wageningen University - ISBN 9789463436748 - 154
food - physiological functions - feeding behaviour - food preferences - perception - hormones - responses - neurohormonal control - stomach bypass - gastric bypass - satiety - voedsel - fysiologische functies - voedingsgedrag - voedselvoorkeuren - perceptie - hormonen - reacties - neurohormonale controle - maag bypass - buik bypass - verzadigdheid

Food reward is an important driver of food intake and triggers consumption of foods for pleasure, so-called hedonic eating, even in the absence of any energy deficits. Hedonic eating can trigger overeating and may therefore lead to obesity. Given the rise in obesity rates and the health risks associated with being obese, hedonic eating and food reward are important phenomena to study. This thesis aimed to add on to the existing knowledge on food reward. The phenomenon was approached from a behavioural, sensory and (neuro)physiological perspective in healthy, lean and in obese gastric bypass populations.

For the behavioural perspective, the main outcome measure used in this thesis was food preferences. To be able to study food preferences for four macronutrient and two taste categories, a new food preference task was developed. In chapter 2, the development and validation of the Macronutrient and Taste Preference Ranking Task (MTPRT) were described. The MTPRT uses a ranking method to determine preferences for four macronutrient (high-carbohydrate, high-fat, high-protein, low-energy) and two taste (sweet and savoury) categories.

For the sensory and physiological perspective, focus was put on the endocannabinoid system (ECS): a neuromodulatory system that plays a role in food reward. To gain more insight into this role, the effect of ECS modulation with pharmacological challenges on sensory perception of sweet taste and on food preferences were studied, as well as endocannabinoid responses to food intake. In chapter 3 it was shown that inhaling Cannabis with low doses of Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) does not alter sweet taste intensity perception and liking in humans, nor does it affect food preferences. Vice versa, in chapter 4 it was found that liking of a food taste does not affect endocannabinoid responses to food intake, after controlling for expectations. When palatability of the food is unknown until the first bite, response of endocannabinoids, ghrelin and pancreatic polypeptide did not differ between a palatable and a neutral food across anticipatory, consummatory and post-ingestive phases of food intake. Endocannabinoid and ghrelin plasma concentrations decreased after food intake, which suggests an orexigenic function for endocannabinoids.

In chapters 5, 6 and 7, studies with patients who underwent Roux-en-Y gastric bypass surgery were described. These studies were intended to gain more insight into alterations in food reward in relation to (morbid) obesity and in response to surgical treatment by RYGB surgery.

First, in chapter 5 food preferences were assessed before, and at two months and one year after RYGB. It was shown that patients have decreased preference for high-carbohydrate and high-fat foods, and increased preference for low-energy foods after compared with before surgery. In addition, liking ratings for the high-carbohydrate and high-fat foods were decreased after RYGB surgery, whereas liking of low-energy products changed minimally. Potential mechanisms behind these alterations in food preferences include changes in neural processing of food cues and changes in appetite-related gut hormones.

In chapter 6, it was shown that alterations in food preferences after RYGB surgery are indeed related to changes in neural activation in response to food cues. With regards to the appetite-related hormones it was shown that plasma concentrations of the endocannabinoid anandamide were increased after compared with before surgery. Plasma concentrations of other endocannabinoids and ghrelin did not change. Moreover, changes in endocannabinoid or ghrelin concentrations did not correlate with changes in food preferences or neural response to food cues. Together, these results suggest that changes in neural processing of food cues contribute to changes in food preferences towards low-energy foods, and provide a first indication that the endocannabinoid system does not seem to play a role in this process.

To gain more insight into behavioural responses to food cues, a response-inhibition paradigm was used in chapter 7, in which response-inhibition to high-energy and low-energy food cues was assessed during brain imaging. The behavioural data did not show differences in performance when comparing before and two months after RYGB surgery. The brain imaging data showed that activation in reward-related brain areas was decreased in response to both high- and low-energy food pictures after RYGB surgery. Also, prefrontal brain areas were more activated in response to the high-energy pictures, which suggests improved response inhibition.

In conclusion, the findings in this thesis show that modulating the ECS with low doses of THC and CBD does not influence sweet taste perception and liking and food preferences, and vice versa, food taste liking in the absence of expectations does not affect endocannabinoid responses to food intake. With regards to RYGB surgery it was uncovered that changes in food preferences after RYGB surgery are related to altered brain reward processing, but no relation with changes in endocannabinoid tone was found. The success of RYGB surgery and the changes in food choice might in part be caused by an improved inhibitory response to high-energy foods.

“Everything tastes different” : The impact of changes in chemosensory perception on food preferences, food intake and quality of life during chemotherapy in cancer patients
Vries, Yfke Carlijn de - \ 2017
University. Promotor(en): Kees de Graaf; H.W.M. van Laarhoven, co-promotor(en): R.M. Winkels; Sanne Boesveldt. - Wageningen : Wageningen University - ISBN 9789463436090 - 169
perception - sensory evaluation - food intake - quality of life - food preferences - neoplasms - taste - macronutrients - drug therapy - breast cancer - perceptie - sensorische evaluatie - voedselopname - kwaliteit van het leven - voedselvoorkeuren - neoplasma - smaak - macronutriënten - geneesmiddelenbehandeling - borstkanker

Taste and smell changes are common side effects during chemotherapy in cancer patient and may have an impact on food preferences, food intake and quality of life. However, these relations have hardly been studied systematically in specific cancer populations. The overall aim of this thesis was to assess how the sense of taste and smell change upon treatment with chemotherapy in breast cancer and oesophagogastric cancer patients, and to investigate their consequences in terms of food preferences, food intake and quality of life.

To measure food preferences for both macronutrients and tastes, the Macronutrient and Taste Preference Ranking Task (MTPRT) was developed. in chapter 2, it was shown that by inducing sensory specific satiety for a standardized sweet and savoury meal, it is possible to detect shifts in preferences for both tastes and macronutrients with the MTPRT, and that these results are reproducible.

In Chapter 3 we studied objective and subjective taste and smell perception and food preferences in advanced oesophagogastric cancer patients undergoing palliative chemotherapy. The result showed that only objective taste function decreases during chemotherapy, but other chemosensory measures were unchanged. A lower subjective taste perception was related to a lower preference for high-protein products. Therefore it is important to consider patients’ taste perception, when providing dietary advice to OGC patients

Chapter 4 describes a study with similar outcome measures as chapter 3, but in breast cancer patients at several time points during and after chemotherapy, and compared to a healthy control group. The study showed that breast cancer patients like high-protein, high-fat, sweet and savoury products less during chemotherapy, thus showing altered preferences for macronutrients, but not for tastes. Furthermore, results showed a temporary decrease in taste and smell perception during chemotherapy. These findings show that patients should be informed prior to treatment on chemosensory changes, and that these changes should be monitored during treatment due to the consequences for nutritional intake and quality of life

In chapter 5 we assessed the dietary intake of breast cancer patients before and during chemotherapy compared to a healthy control group, and associations with experienced symptoms during chemotherapy. It was shown that symptoms induced by chemotherapy were associated with lower total energy, protein and fat intake, which was manifested by a lower intake of specific food groups. Therefore, to ensure an optimal dietary intake during chemotherapy, it is important to monitor nutritional status and symptom burden during chemotherapy in breast cancer patients.

To better understand the impact of chemosensory changes during chemotherapy on daily life, 13 advanced oesophagogastric cancer patients were interviewed (see chapter 6). Patients described a substantial impact of chemosensory and food-related changes on daily life (by changing daily routines), social life (eating being less sociable) and roles in the household (changing roles in cooking and grocery shopping).

Finally, in chapter 7, we assessed the association between self-reported taste and smell perception and quality of life in breast cancer patients. A worse taste and smell perception was associated with a worse global quality of life, role, social and emotional functioning shortly after chemotherapy. In patients treated with trastuzumab, a worse taste and smell perception was still associated with quality of life, social and role functioning half a year after chemotherapy had ended.

From the studies in this thesis we can conclude that chemotherapy mainly affects the sense of taste. The subjective perception of taste was associated with a lower preference for food products and lower energy intake. This indicates that it is not necessarily an actual change in the sense of taste or smell that has an impact on patients, but flavour perception as a whole and potentially a lower enjoyment of food. Moreover, these perceived changes in taste and smell can have a substantial impact on cancer patients’ lives, in a practical way by changing daily patterns of eating, but also socially and in roles in the household. A changed chemosensory perception during chemotherapy may lead to a worsened nutritional status, and could thereby negatively impact the response to chemotherapy. Therefore chemosensory perception should be monitored during chemotherapy. Future studies should further investigate the mechanisms behind chemosensory changes, factors that contribute to subjective taste perception and possible interventions to alleviate chemosensory changes during chemotherapy.

Framing nature : searching for (implicit) religious elements in the communication about nature
Jansen, Peter - \ 2017
University. Promotor(en): Henk Jochemsen, co-promotor(en): Jozef Keulartz; J. van der Stoep. - Wageningen : Wageningen University - ISBN 9789463431323 - 200
nature - policy - netherlands - communication - religion - case studies - frames - perception - public authorities - landscape experience - identity - natuur - beleid - nederland - communicatie - religie - gevalsanalyse - geraamten - perceptie - overheid - landschapsbeleving - identiteit

This PhD thesis is about communication concerning nature in the Netherlands. The purpose of this exploratory study is to take both a theoretical and an empirical look at whether (implicit) religious elements play a role in this communication about nature in the Netherlands.

In this PhD thesis it is argued that the role of communication practitioners is to signal, articulate, and interpret normative elements in the discourse. In other words, to make (non-) congruent frames explicit and clarifying the associated world views in the discourse, including that of the government itself. The government has to be impartial as possible in its communications, but the communications about nature shows that there are questions to be asked about this neutrality. Although not explicit, but through the communications of NGOs, who operate as delegated executors of the Dutch nature policy in the context of this PhD thesis, certain images, i.e., frames regarding nature are communicated. However, the question is raised to what extent the government, based on its alleged neutrality, should condition the communication of NGOs. Here, tension can be observed. If nature conservation NGOs (explicitly) communicate a specific vision about nature, using ‘religious subtexts’, the government appears to support these ‘subtexts’. For nature conservation NGOs, it is appropriate to put forth a certain opinion to raise support for their actions among the public. However, in this PhD thesis it is argued that it is not the responsibility of the government to promote a specific religiously phrased view of nature and nature policy. Hence, this PhD thesis reveals a necessity for reflection on the relationship between government and NGOs regarding their communication, i.e., awareness of distinction and a need for mutual adjustment in the case of close cooperation.

The results of this PhD thesis are placed in a broader cultural context with respect to nature development. A paradox is highlighted: creating nature ‘according to our view of nature’ and, simultaneously, wanting to experience wilderness-nature, preferably without too much human influence. This paradox appears to form a cultural basis for many new nature development projects. In other words, nature development is no longer just driven by ecological interests. In today’s ‘wilderness desire’, a certain form of anthropocentric thinking also manifests, because it focuses on the human experience of nature. In addition, because (new) nature projects can be places to have meaningful experiences, in this PhD thesis it is concluded that (new) nature projects, such as Tiengemeten, not only have ecological value, but societal value as well. It is also argued that in a secular society, we should not lose sight of the mediating role of creating and maintaining nature parks. Designing or maintaining natural areas in a certain way can create conditions for certain meaningful experiences. With our designing vision and communication, we can reap ‘benefits’ from nature. With this conclusion, this PhD thesis shines a different light on the concept of nature development and, indirectly, on the Dutch nature policy.

Finally, this PhD thesis shows that religious elements play a role in the communication about nature. These are linked to meaningful experiences that people can have in nature. A religious depth dimension can be discovered in meaningful experiences. This religious depth dimension is the reason that there are ‘religious subtexts’ in the communication about nature. However, the word ‘subtext’ is crucial. The communication about nature is ‘religionised’ to some extent, but there is no mentioning of a personal God or other reference to a supernatural reality. This PhD thesis also shows that the religious depth dimension does not explicitly come to the fore in what visitors are saying. This means that this PhD thesis, in addition to questioning the appropriateness of ‘religious subtexts’ in the communication about nature, also doubts whether those ‘subtexts’ are convincing from visitors’ perspective.

Rivierenland leeft! Verbinden door samenwerking : Quickscan naar trends, kansen en opgaven met betrekking tot de leefbaarheid in Regio Rivierenland
Gies, T.J.A. ; Nieuwenhuizen, W. - \ 2017
Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 2777) - ISBN 9789463430791 - 41
levensomstandigheden - perceptie - omgevingspsychologie - milieu - rivierengebied - living conditions - perception - environmental psychology - environment
Leefbaarheid gaat over prettig wonen, werken en leven en is daarom is een belangrijk thema voor Regio Rivierenland, een samenwerkingsverband van tien gemeenten, te weten Buren, Culemborg, Geldermalsen, Lingewaal, Maasdriel, Neder-Betuwe, Neerrijnen, Tiel, Zaltbommel en West Maas en Waal. In deze quickscan brengen we de belangrijkste ontwikkelingen m.b.t. de leefbaarheid in beeld. We geven inzicht in de kansen en bedreigingen waarin naast de huidige situatie ook de verwachte ontwikkelingen en trends voor Regio Rivierenland geschetst worden. Daarmee concretiseren we de belangrijkste opgaven en uitdagingen voor de komende jaren in regio Rivierenland.
Double emulsions as fat replacers : linking emulsion design to stability and sensory perception
Oppermann, Anika - \ 2017
University. Promotor(en): Kees de Graaf, co-promotor(en): Markus Stieger; Elke Scholten. - Wageningen : Wageningen University - ISBN 9789463430722 - 186
fats - fat - sensory sciences - sensory evaluation - emulsions - perception - gelation - vetten - vet - sensorische wetenschappen - sensorische evaluatie - emulsies - perceptie - gelering

The use of double (w1/o/w2) emulsions, in which part of the oil is replaced by small water droplets, is a promising strategy to reduce oil content in food products. For successful applications, (1) significant levels of fat reduction (i.e. significant amounts of water inside the oil droplets) have to be achieved, (2) double emulsions have to be stable against conditions encountered during processing and storage, and (3) the mouthfeel and sensory perception have to be similar to that of full-fat equivalents. With the present work, significant progress was made in understanding the complex relations between double emulsion design, achievable levels of fat reduction, emulsion stability and sensory perception. We show that through careful emulsion design, stable double emulsions with high levels of fat reduction (up to 50%) can be obtained while maintaining fat-related sensory properties, making double emulsions a promising approach for the development of fat-reduced food products.

Resultaten van 10 jaar daarmoetikzijn voor de provincie Zuid-Holland
Goossen, C.M. - \ 2017
Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 2781) - 27
landschap - perceptie - natuur - omgevingspsychologie - zuid-holland - landscape - perception - nature - environmental psychology
Op basis van 8.935 bezoekers van de websites www.daarmoetikzijn.nl en myplacetobe.eu uit de provincie Zuid-Holland is een analyse gemaakt naar de aantrekkelijkheid van het landschap. Het gemiddelde rapportcijfer van het landschap in Zuid-Holland is de afgelopen tien jaar een zes en de laatste jaren dalend. Vooral bebouwing draagt negatief bij aan het rapportcijfer, maar ook bedrijventerreinen, industriegebieden en geluid van auto’s, treinen, vliegverkeer en bossen. Heide-, zand- en duingebieden leveren daarentegen een positieve bijdrage aan het rapportcijfer, evenals hoogteverschillen. Deze zes, van de vijftien, gebruikte indicatoren verklaren voor 8 procent het rapportcijfer. Circa een derde van de bezoekers (32 procent) uit Zuid-Holland geeft een onvoldoende aan het landschap rond de eigen woonplaats. Ruimtelijk gezien krijgt echter het grootste deel van het landschap in Zuid-Holland een voldoende. Bos is het meest gewilde landschapstype. Twee derde van de bezoekers wil bezienswaardigheden hebben in het ideale landschap en geluidbelasting, horizonvervuiling en drukte door recreatieve fietsers worden als storend ervaren.
Farmers’ perception of opportunities for farm development
Methorst, Ron - \ 2016
University. Promotor(en): Han Wiskerke, co-promotor(en): Dirk Roep; Jos Verstegen. - Wageningen : Wageningen University - ISBN 9789462579439 - 192
farm development - perception - agriculture - entrepreneurship - case studies - sociology - bedrijfsontwikkeling in de landbouw - perceptie - landbouw - ondernemerschap - gevalsanalyse - sociologie

Differences in the perception of opportunities for farm development is researched in this thesis in relation to differences in the embedding of the farm in the socio-material context. This study contributes to a Sociology of Entrepreneurship in focusing on the decision-maker specific aspects using the concepts Opportunity Identification, Strategic Decision-Making and Embeddedness. In a case study of family dairy farmers operating in a highly comparable socio-material context at the level of the case study, a mix of quantitative and qualitative data were used to analyse differences at the level of the decision-makers on the family farm. Based on the perceived viability of 15 opportunities for farm development to contribute to farm income, four clusters of opportunities were found that represent different farm development strategies: 1) maximising production; 2) optimising the use of own resources; 3) diversifying production; and 4) ending dairy farming. Personal views and preferences showed to be the most influential driver, mediating the influence of the combined set of seven drivers on the perception of opportunities. Taking the perspective of embeddedness, every farm development strategy appeared to have different sets of relations for three dimensions of the socio-material context: the socio-cultural context, the dairy value chain and the use of resources for production. These sets of relations differ on a scale ranging from more ‘close’ to more ‘stretched’ set of relations, resembling a mixing paned of three sliders on which the family farmer positions itself, a positioning that is related to personal views and preference. The socio-material characteristics of a farm, thus, result from, and reflect how it is embedded in a set of heterogeneous relations. This finding supports the relevance of a relational perspective on farm development where strategic decision-making is the reiterative process of embedding farm practices in the different sets of relations of the farm with the socio-material context. The farmer’s interpretation of the complex and dynamic relations in the socio-material context affects the identification of opportunities for farm development. Approaching strategic decision-making as the positioning in sets of relations offers a non-normative approach to family farm development in relation to the socio-material context. Awareness of the influence of personal views and preferences combined with a non-normative approach is of relevance for effective policies and support programmes to support the development of vital farms in vital rural areas.

Keywords: family farm, farm development, strategy, opportunity identification, strategic decision-making, embeddedness

Beleefbare natuur: van recreatieve infrastructuur naar bioculturele diversiteit.
Wiersum, K.F. ; Elands, B.H.M. - \ 2016
Vakblad Natuur Bos Landschap 2016 (2016)feb. - ISSN 1572-7610 - p. 14 - 17.
natuur - landschapsbeleving - perceptie - recreatie - biodiversiteit - culturele psychologie - ecosysteemdiensten - natuurwaarde - cultuur - bosbeheer - nature - landscape experience - perception - recreation - biodiversity - cultural psychology - ecosystem services - natural value - culture - forest administration
Traditioneel richt de aandacht van het bosbeheer voor een beleefbare natuur zich op de ontwikkeling van de recreatieve infrastructuur. Tegenwoordig krijgen ook andere vormen van samenleven met natuur aandacht. Deze ontwikkeling wordt weerspiegeld in het nieuwe begrip “bioculturele diversiteit”.
Groen voor gezondheid: wat hebben gezondheidsprofessionals nodig? : Achtergronddocument
Hermans, C.M.L. ; Lemmens, L. ; Postma, A. - \ 2015
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2665) - 49
natuur - openbaar groen - gezondheid - volksgezondheid - omgevingspsychologie - perceptie - welzijn - stress - lichamelijke activiteit - beweging - nature - public green areas - health - public health - environmental psychology - perception - well-being - physical activity - movement
Natuur werkt positief op gezondheid en welbevinden van mensen. De werkingsmechanismen achter deze positieve relatie zijn bekend: stress vermindert, lichamelijke activiteit neemt toe, de sociale cohesie in de buurt verbetert. Toch wordt natuur nauwelijks ingezet door professionals uit de eerste lijn of publieke gezondheid. Wat belemmert hen en wat zijn de oplossingen?
Oral coatings: a study on the formation, clearance and perception
Camacho, S. - \ 2015
University. Promotor(en): Kees de Graaf, co-promotor(en): Markus Stieger; F. van de Velde. - Wageningen : Wageningen University - ISBN 9789462575653 - 223
afdeklagen - eiwitten - orale toediening - tong - mond - smering - emulsies - in vivo experimenten - sensorische evaluatie - perceptie - dynamica - zoetheid - fluorescentie - coatings - proteins - oral administration - tongue - mouth - lubrication - emulsions - in vivo experimentation - sensory evaluation - perception - dynamics - sweetness - fluorescence

Oral coatings are residues of food and beverages that coat the oral mucosa after consumption. Several studies have reported on the lubrication properties in mouth, and the after-feel and after-taste impact of oral coatings. Further, oral coatings have been suggested to influence subsequent taste perception. Although it is well known that oral coatings can influence sensory perception, there was little information available on the chemical composition and physical properties of oral coatings. As such, the aim of this thesis was to understand which factors influence the composition of oral coatings and their sensory perception.

This study started with the development of an appropriate calibration method for an already described methodology to quantify oil oral coatings: in vivo fluorescence. Further, the samples studied were shifted from pure oil (used on previous studies) to a more realistic food beverage: o/w emulsions. Pig´s tongues are known to be a good model of human tongue. As such, Chapter 2 used pig´s tongues on the calibration of the method, to mimic the fluorescence in mouth of oil coatings. On chapter 2, Confocal Scanning Laser Microscopy images showed that stable o/w emulsions (1-20% (w/w)) stabilised by Na-caseinate created individual oil droplets on the surface of the pigs tongue, as such a new descriptor for oil coatings was developed. Oil fraction, i.e. mass of oil per surface area of the tongue, was shown to be higher on the back compared to the front anterior part of the tongue. This is thought to be due to the morphology of the tongue and abrasion of the oil coating owed to the rubbing with the palate. Further, in vivo measurements showed that oil fraction deposited on the tongue increased linearly with oil content of o/w emulsions. Coating clearance from the tongue was a fast process with around 60% of the oil being removed on the first 45s. After-feel perception (Fatty Film and Flavour Intensity) was shown to be semi-logarithmic related to oil fraction on the tongue.

Chapter 3, further investigated different properties of 10% (w/w) o/w emulsions that influence the oil fraction deposited on the tongue, its clearance and after-feel perception. Three different properties were studied: protein type, protein content and viscosity of the o/w emulsions. To study the influence of protein type, two different proteins which behave differently in-mouth were studied: Na-caseinate - creates emulsions which do not flocculate under in mouth conditions, and lysozyme – creates emulsions which flocculate under in mouth conditions. To study the influence of protein content, three concentrations of Na-caseinate and lysozyme were used (0.2, 3, 5.8% (w/w) all in excess to stabilize the water/oil interface). To study the influence of viscosity of o/w emulsions, three o/w emulsions stabilized with 3% (w/w) Na-caseinate were thickened with varying concentrations of xanthan gum (0-0.5%) (w/w).

Generally, the irreversible flocculation of lysozyme stabilized emulsions with saliva did not create a significant difference on oil deposition compared to emulsions stabilized with Na-caseinate, immediately after expectoration of the emulsions. Nevertheless, lysozyme stabilised emulsions caused slower oil clearance from the tongue surface compared to emulsions stabilized with Na-caseinate. Protein content had a negative relation with oil fraction on the tongue for lysozyme stabilized emulsions and no relation for Na-caseinate stabilized emulsions. The presence of thickener decreased deposition of oil on tongue, although viscosity differences (i.e., thickener content) did not affect oil fraction. After-feel perception of creaminess and fatty-film was strongly influenced by the presence of thickener likely due to lubrication in-mouth, i.e., the higher the concentration of thickener in the emulsions the stronger was the perception. Oral coatings perception was further influenced by the protein used in the emulsions, with Na-caseinate stabilised emulsions creating coatings with higher perception on creaminess and fatty-film.

Chapter 2 and chapter 3 provided knowledge on the deposition and clearance of oil coatings, but little was known on the formation of oil coatings. Chapter 4 focused on the formation of oil coatings formed by Na-caseinate stabilised o/w emulsions (1-20% (w/w)). The formation of oil coatings was a rapid process, where the maximum oil deposition was achieved at normal drinking behaviour (~3s). Further, in Chapter 4 we investigated the hypothesis often referred on literature, in which oil coatings form a physical barrier which prevents tastants to reach the taste buds, and thus create a reduction on taste perception. It was concluded that oil coatings formed by emulsions within one sip did not affect subsequent sweetness perception of sucrose solutions. We suggested that the oil droplets deposited on the tongue (as seen on chapter 2) did not form a hydrophobic barrier that is sufficient to reduce the accessibility of sucrose to the taste buds and consequently does not suppress taste perception.

Previous chapters focused on oral coatings formed by liquid o/w emulsions, however studies describing oral coatings formed by semi-solids and solids are scarce. As such, chapter 5 focused on the formation, clearance and sensory perception of fat coatings from emulsion-filled gels. Four emulsion-filled gelatin gels varying in fat content and type of emulsifier (whey protein isolate - created fat droplets bound to matrix; tween 20 - created fat droplets unbound to matrix) were studied. As in for oil coatings formed by liquid o/w emulsions, fat coatings formed by emulsion-filled gels reach their maximum deposition in the first seconds of mastication. This suggests that the first bites are the most relevant for the formation of fat coatings on the tongue. Further, fat fraction deposited on tongue increased when oral processing time of the gels increased. This trend was clearer for gels with higher fat content (15%) compared to gels with lower fat content (5%). Fatty perception increased with increasing mastication time, and decreased after expectoration with increasing clearance time. Fat fraction deposited on tongue and fatty perception are higher in gels with unbound droplets compared to bound droplets, as well as in gels with 15% fat compared to 5% fat.

To elucidate the role of protein on oral coatings, Chapter 6 focused on the development of a method to quantify protein in the oral coatings. Further, Chapter 6 studied the influence of protein content, in-mouth protein behaviour (lysozyme - protein which creates flocs with saliva vs. Na-Caseinate - protein which does not create flocs with saliva) and presence of thickener on the formation of protein oral coatings and sensory perception of protein coatings. Protein coatings were collected from the front and middle part of the anterior tongue using cotton swabs after subjects orally processed protein solutions for different time periods. Protein concentration of the coating (mass protein/mass coating) was quantified with the Lowry method. Similarly to oil/fat coatings, results show protein coatings are formed rapidly, reaching maximum deposition on the first seconds of the samples´ oral processing. Further, different protein in mouth-behaviour (Na-caseinate vs. lysozyme) did not create differences on protein deposition on the tongue. Presence of xanthan-gum in the processed samples decreased protein deposition on the tongue, compared to when samples without xanthan-gum were processed. The perception of protein coatings was strongly influenced by the viscosity and protein used in the samples. Higher viscosity of the samples lead to higher intensity on creaminess and thickness. Lysozyme samples created coatings with high sweetness and astringent intensity, which is related to the molecular structure of the protein.

Changes in the viscosity of beverages can cause changes in thickness perception. The changes in thickness perception can be accompanied by differences in other sensory properties, such as sweetness and creaminess which might be undesirable when reformulating beverages or developing new products. Knowledge on the differences by which viscosity of beverages can be modified to create a difference in sensory perception is currently lacking. Chapter 7 focus on the determination of the Just Noticeable Difference (the minimal difference that can be detected between two stimuli) for thickness perception of beverages. Oral thickness sensitivity (K=0.26) was found to be comparable to literature values for kinesthetic food firmness and spreadability, creaminess, sourness and bitterness perception.

The aim of this thesis was to determine and characterize factors influencing oral coatings and their sensory perception. For this purpose, reliable methods to quantify oil and protein deposited on the tongue had to be developed to later study the macronutrients deposition. Further, the influence of stimulus properties on the formation and clearance dynamics of oral coatings and their impact on sensory perception were investigated.

Bolus matters: impact of food oral breakdown on dynamic texture perception
Devezeaux de Lavergne, M.S.M. - \ 2015
University. Promotor(en): Tiny van Boekel, co-promotor(en): Markus Stieger; F. van de Velde. - Wageningen : Wageningen University - ISBN 9789462574496 - 227
textuuranalyse - textuur - voedsel - structuur - eigenschappen - perceptie - spijsvertering - gels - elektromyografie - masticatie - kwalitatieve analyse - worstjes - texture analysis - texture - food - structure - properties - perception - digestion - electromyography - mastication - qualitative analysis - sausages

Background and aims:

Texture is an important, yet complex, quality attribute of food. Food structure and properties can be linked to texture perception during the first bite. However, the perception of attributes during chew down is more difficult to explain, as food requires to be broken down to be swallowed safely. Food oral processing, which is a recent discipline connecting food science to the physiology of the eating process, is considered to be the key for understanding dynamic food texture perception. The aim of this thesis is to understand the link between food properties and texture perception by investigating oral food breakdown, in simple model foods.

Methods:

Gels were used as a model for soft solid foods. Several properties of the gels were controlled by modifying the composition of gels, including fracture stress and fracture strain, oil droplets binding to the gels matrix, melting, serum release and mechanical contrast. The texture perception of the gels was measured using several sensory methods. Qualitative descriptive analysis (QDA), progressive profiling and temporal dominance of sensations (TDS) were compared in the assessment of dynamic texture perception. In order to link gel properties to texture perception, the oral processing of gels was measured through analyses on the gel bolus and measurements of chewing behaviour. Gel boli were expectorated at various stages of oral processing and were analysed for gel fragments size and number, mechanical properties and saliva incorporation. These analyses were used to quantify the degree of breakdown of gels and to relate bolus properties to changes in texture perception. Chewing behaviour was measured using Electromyography (EMG) to understand the role of oral processing behaviour in bolus formation and dynamic texture perception.

Results:

Dynamic texture perception of gels could be measured by QDA, progressive profiling and TDS which were complementary methods. Fracture properties of gels could predict the perception of first bite texture attributes. Fracture stress and fracture strain were correlated to first bite firmness and brittleness respectively. During chew down, the link between gel properties and texture perception became less clear. Nonetheless, fracture properties and other gels properties, such as melting and serum release, related to chew down perception. Bolus properties depended on gel properties, but related better to chew down texture perception than gel properties. Mainly changes in mechanical properties and fragmentation of the bolus could explained the perception of complex texture attributes, such as creaminess and graininess respectively. Chewing behaviour depended on products properties. In addition, chewing behaviour impacted the formation of the bolus and could result in differences in dynamic texture perception between groups of individuals.

Conclusions:

The oral breakdown of food is a valuable input to understand the perception of complex chew down texture attributes. Such an input could be used to design foods with a desired texture sensory profile for reformulation of foods fitting in a healthier diet or foods for target consumer groups.

A technological and physiological integrated approach for appetite control : from identification of novel biomarkers to development of new functional ingredients
Mennella, I. - \ 2015
University. Promotor(en): Vincenzo Fogliano, co-promotor(en): P. Vitaglione. - Wageningen : Wageningen University - ISBN 9789462575448 - 138
eetlustcontrole - perceptie - voedselvoorkeuren - speeksel - cannabinoïden - biomarkers - ingrediënten - ontwikkeling - gewichtscontrole - appetite control - perception - food preferences - saliva - cannabinoids - ingredients - development - weight control

A technological and physiological integrated approach for appetite control.

From identification of novel biomarkers to development of new functional ingredients.

Human dietary behaviour is driven by homeostatic, hedonic and environmental factors. Foods can

influence these factors throughout extrinsic (marketing suggestions, portion sizes, form) and

intrinsic characteristics (taste, flavour, smell, texture). In turn biochemical response and

psychological traits influenced food taste, flavour, smell and texture perception determining the

hedonic value of a meal. This interplay between the food and the subjective psychophysiological

response determine the control of energy intake, therefore must be considered in developing food

for appetite control.

In the present thesis four human studies are described. Of these two were conducted to investigate

the role of the saliva and the endocannabinoids system in the food preference and liking during the

cephalic phase of digestion. We found out that salivary enzymes activity are influenced by

nutritional status, food preference and food habits. Moreover, food palatability influenced some

plasma endocannabinoid and N-acylethanolamine concentrations during the cephalic phase

response and indicated that 2-arachidonoylglycerol and pancreatic polypeptide can be used as

biomarkers of food liking in humans. These findings can have interesting implications in designing

foods for appetite control:

­ salivary enzymatic activity must be considered because it influence taste and texture

perception and consequently food choice;

­ the measure of 2-arachidonoylglycerol can offer the possibility to merge the sensory and

biochemical approach to compare the satiating and rewarding capacity of foods.

The other two studies investigated the potential satiating effect on the short term energy intake of

specific food ingredients. As previous in animal studies shown, we demonstrated (chapter 4) that

also in humans the circulating oleoylethanolamide levels can be modulated by the fatty acid

composition of a meal and this can influence the short-term energy intake. Therefore, we

highlighted the anorexigenic effect of the oleoylethanolamide that can be a target of specific food

ingredients. In the study described in the chapter 5, we aimed in assessing the appetite control

capability of bitter compounds. The ingredient was microencapsulated with the double aim to avoid

the (not palatable) taste perception in the mouth and to deliver the compounds directly in the

gastrointestinal tract and target the enteroendocrine bitter taste receptors. We showed that

microencapsulated bitter compounds are effective to reduce daily energy intakes in humans. This

study demonstrated that sense the taste receptors directly in the gastrointestinal tract may be a valid

way to trigger satiety and control appetite.

The general conclusions of the present thesis are that a fine design of ingredients for appetite

control is necessary to develop novel foods for appetite control that has to take in account from one

side the hedonic value from the other side the functionality.

Colourful green : immigrants’ and non-immigrants’ recreational use of greenspace and their perceptions of nature
Kloek, M.E. - \ 2015
University. Promotor(en): Matthijs Schouten; J.J. Boersema. - Wageningen : Wageningen University - ISBN 9789462574113 - 194
natuur - recreatieactiviteiten - recreatie - omgevingspsychologie - perceptie - immigranten - nature - recreational activities - recreation - environmental psychology - perception - immigrants
Natuurorganisaties, waaronder Staatsbosbeheer, hebben sterke vermoedens dat allochtone Nederlanders minder in de natuur komen dan autochtone Nederlanders. Ook bij natuurorganisaties in andere westerse landen, zoals in Duitsland en het Verenigd Koninkrijk, leeft het idee dat allochtonen weinig in de natuur komen. Omdat recreatie in de natuur mogelijk het draagvlak voor natuurbeheer vergroot en een positief effect heeft op gezondheid, welzijn en sociale integratie, wordt ‘onder-participatie’ in recreatie in de natuur als zorgelijk gezien. Er zijn echter weinig harde cijfers over het natuurbezoek van allochtonen. Ook is weinig bekend over verschillen in recreatief gedrag tussen groepen allochtonen van diverse komaf. In dit proefschrift is onderzocht hoe allochtonen en autochtonen in Nederland recreëren in de groene ruimte en hoe ze denken over natuur
Maatschappelijk gedragen landschapsregeneratie
Kasper, L. ; Bijker, F. ; Roncken, P.A. ; Maat, H. - \ 2015
Landschap : tijdschrift voor Landschapsecologie en Milieukunde 32 (2015)2. - ISSN 0169-6300 - p. 80 - 89.
landschap - landgebruik - ecosysteemdiensten - duurzaamheid (sustainability) - perceptie - modellen - actieonderzoek - landscape - land use - ecosystem services - sustainability - perception - models - action research
Een model wordt gepresenteerd, dat os ontwikkeld om de steun voor landschappelijke regeneratie te vergroten door inzicht te bieden in de relatie tussen landschap en lokale bevolking. Het Sociale Terugkoppeling Model brengt tegengestelde belangen van lokale bevolking, bestuurders en experts in kaart die tot weerstand tegen verandering kunnen leiden; het toont voorwaarden voor succesvolle landschapsregeneratie en biedt een reflectie op specifieke elementen van betrokkenheid waarmee lokale ondersteuning van landschappelijke regeneratie op een mideellange termijn mogelijk is.
De potentie van natuurcombinaties : inzicht en reflecties op de meerwaarde van een nieuw concept
Fontein, R.J. ; Michels, R. ; Linderhof, V.G.M. ; Goossen, M. ; Graaff, R.P.M. de - \ 2015
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2648) - 55
natuurbeleid - natuurontwikkeling - regionale planning - perceptie - innovaties - nederland - nature conservation policy - nature development - regional planning - perception - innovations - netherlands
In de Rijksnatuurvisie staat het concept Natuurcombinaties centraal. Natuurcombinaties zijn initiatieven die tegelijkertijd de natuur én andere maatschappelijke functies versterken. Deze studie reflecteert op het concept Natuurcombinaties, biedt een methodiek om natuurcombinaties inzichtelijk te maken, geeft inzicht in de meerwaarde van natuurcombinaties voor verschillende functies en het natuurbeleid en gaat in op de randvoorwaarden, kansen en belemmeringen van natuurcombinaties en de rol van het rijk bij het stimuleren hiervan.
Genetic improvement in indigenous chicken of Ethiopia
Woldegiorgiss, W.E. - \ 2015
University. Promotor(en): Johan van Arendonk, co-promotor(en): Liesbeth van der Waaij; T. Dessie. - Wageningen : Wageningen University - ISBN 9789462573161 - 130
kippen - pluimvee - inheems vee - genetische verbetering - houding van boeren - perceptie - kippenrassen - prestatieniveau - dierveredeling - ethiopië - fowls - poultry - native livestock - genetic improvement - farmers' attitudes - perception - fowl breeds - performance - animal breeding - ethiopia

Abstract

Wondmeneh Esatu Woldegiorgiss (2015). Genetic improvement in indigenous chicken of Ethiopia. PhD thesis, Wageningen University, the Netherlands

This thesis considered various approaches to study the potential for improvement of village poultry production system using improved indigenous chicken. The approaches were structured survey questionnaire, village poultry simulation model (VIPOSIM), Heckman two-step model (econometric model), and experiments involving laboratory and field. First factors that determine the probability and intensity of adoption of exotic chickens were assessed. The probability of adopting exotic chickens was found to be positively affected by access to an off-farm income and negatively by livestock income. The intensity of adoption was negatively affected by being male household head, having a larger farm size, and having livestock income. Then, perceptions of farmers towards village poultry and impacts of interventions on flock and economic performance were assessed. Farmers’ perceptions affected their decisions about implementation of interventions, and interventions increased productivity but only in a few cases the increased revenues outweighed the additional costs. Subsequently, the evaluation of the breeds was conducted by comparing the natural antibody and productivity of improved indigenous chicken with crossbred, commercial and unimproved indigenous chickens. The results revealed that not only the NAb levels but also the effect of NAbs on survival differ between indigenous and improved breeds. NAb levels are associated with survival in commercial layer breed, but reduced survival in indigenous chickens placed in confinement. Improved indigenous chickens showed higher performance than unimproved one for all traits measured on-station, but remains lighter and developed more into a laying type than meat through the short-term selective breeding program. Overall, the present studies indicate that interventions need to be tailored towards the local situation to ensure that they lead not only to improved productivity but also to improved income.

Temporal and spatial variability of urban heat island and thermal comfort within the Rotterdam agglomeration
Hove, B. van; Jacobs, C.M.J. ; Heusinkveld, B.G. ; Elbers, J.A. ; Driel, B.L. van; Holtslag, A.A.M. - \ 2015
Building and Environment 83 (2015). - ISSN 0360-1323 - p. 91 - 103.
klimaatverandering - temperatuur - perceptie - stedelijke gebieden - ruimtelijke variatie - variatie in de tijd - rotterdam - climatic change - temperature - perception - urban areas - spatial variation - temporal variation - air-temperature - street geometry - canyon geometry - climate zones - land-use - environment - areas - radiation - impact - fluxes
This paper reports on temporal and spatial variability of local climate and outdoor human thermal comfort within the Rotterdam agglomeration. We analyse three years of meteorological observations (2010–2012) from a monitoring network. Focus is on the atmospheric urban heat island (UHI); the difference in air temperature between urban areas and rural surroundings. In addition, we calculate the Physiologically Equivalent Temperature (PET) which is a measure of thermal comfort. Subsequently, we determine the dependency of intra-urban variability in local climate and PET on urban land-use and geometric characteristics. During a large part of the year, UHI-intensities in densely built areas can be considerable, under calm and clear (cloudless) weather conditions. The highest maximum UHI-values are found in summer, with 95-percentile values ranging from 4.3 K to more than 8 K, depending on the location. In winter, UHI-intensities are generally lower. Intra-urban variability in maximum UHI-intensity is considerable, indicating that local features have an important influence. It is found to be significantly related to building, impervious and green surface fractions, respectively, as well as to mean building height. In summer, urban areas show a larger number of discomfort hours (PET > 23 °C) compared to the reference rural area. Our results indicate that this is mainly related to the much lower wind velocities in urban areas. Also intra-urban variability in thermal comfort during daytime appears to be mainly related to differences in wind velocity. After sunset, the UHI effect plays a more prominent role and hence thermal comfort is more related with urban characteristics.
Natuurverkenning twee jaar later : over gebruik en doorwerking van Natuurverkenning 2010-2040
Vader, J. ; Bogaardt, M.J. - \ 2014
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-technical report 11) - 61
natuurbeleid - natuur - perceptie - scenario-analyse - inventarisaties - nature conservation policy - nature - perception - scenario analysis - inventories
In dit rapport staat beschreven door wie, hoe en waarvoor de Natuurverkenning 2010-2040 is gebruikt. Dit is onderzocht op basis van deskresearch en interviews. De resultaten worden gebruikt voor de volgende Natuurverkenning. De verkenning is door een brede doelgroep ontvangen en op wordt op diverse manieren gebruikt. Geïnterviewden noemen vooral het onderdeel kijkrichtingen. Kijkrichtingen zijn bruikbaar om natuur mee in te delen, elkaars beeld van natuur te begrijpen, een dialoog op gang te brengen en zelfs vastgelopen discussies mee open te breken. De Natuurverkenning wordt als legitimatie gebruikt voor het bredere denken over natuur en gebruik van natuur. De Natuurverkenning is input voor diverse (beleids)trajecten waarvan de Rijksnatuurvisie 2014 van het ministerie van Economische Zaken één van de belangrijkste is. Gebruik van de Natuurverkenning wordt door diverse factoren beïnvloed. Het interactieve proces met stakeholders, het gebruik van normatieve scenario’s en de beleidscontext zijn een aantal van de belangrijkste
Rapportage onderzoeksproject Genieten aan tafel : een toegepast onderzoek naar maaltijdbeleving in verpleeghuizen
Zeinstra, G.G. ; Atten, M.N. van; Ziylan, C. ; Boelsma, E. ; Peppelenbos, H.W. ; Brok, P. den - \ 2014
Wageningen : Wageningen UR - Food & Biobased Research (Rapport / Wageningen UR Food & Biobased Research 1483) - ISBN 9789462570535 - 86
verpleeghuizen - ouderenvoeding - ouderen - perceptie - volksgezondheid - ziektepreventie - maaltijden - nederland - ondervoeding - voedselconsumptie - nursing homes - elderly nutrition - elderly - perception - public health - disease prevention - meals - netherlands - undernutrition - food consumption
Er komen steeds meer ouderen in Nederland. Zij doen over het algemeen een groter beroep op de gezondheidszorg, wat tot stijgende zorgkosten leidt en een lagere kwaliteit van leven. Eten en drinken speelt een belangrijke rol bij de preventie van ziekte. Hoewel er steeds meer aandacht is voor de voedingsstatus van ouderen en screeningsprocedures steeds meer toegepast worden, laten de laatste metingen in Nederland zien dat 17% van de cliënten in instellingen ondervoed is en dat 28% risico loopt op ondervoeding. Om ziekte en daarmee verhoogde zorgkosten te voorkomen, en om de kwaliteit van leven te optimaliseren, is preventie van ondervoeding bij ouderen noodzakelijk. Het onderzoek ‘Genieten aan tafel’ beoogde de maaltijdbeleving van verpleeghuiscliënten te optimaliseren, met als doel om eetlust, voedingsstatus, functionele status en kwaliteit van leven te verbeteren en zo zorgkosten te verminderen.
Focusgroepdiscussies over pizza en groentesalade met kinderen van 10-12 jaar: resultaten en aanbevelingen voor productontwikkeling
Janssen, A.M. ; Holthuysen, N.T.E. ; Stijnen, D.A.J.M. ; Zeinstra, G.G. ; Vrijhof, M.N. - \ 2014
Wageningen : FBR (Rapport / Wageningen UR Food & Biobased Research 1449) - ISBN 9789461739858 - 86
kinderen - perceptie - pizza's - groenten - salades - voedselconsumptie - consumptiepatronen - voeding en gezondheid - productontwikkeling - nederland - children - perception - pizzas - vegetables - salads - food consumption - consumption patterns - nutrition and health - product development - netherlands
In the Netherlands, the consumption of fruit and vegetables is too low among children. One of the main reasons is that children often do not like to eat vegetables. The focus in the project Healthy food for kids - Kids University was to measure children’s product experience of (more) healthy vegetable foods and to translate gained knowledge into food concepts high in vegetable content developed for children aged 10-12 years. In this report, results of the research aiming to better understand factors that are important for children when eating pizza and vegetable salad, is described. Another goal was to determine what choices children make when they compose their own pizza or vegetable salad.
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