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Previous studies have investigated effects of consumption contexts on food experiences using actual real-life contexts and recreated immersive contexts. The results typically show that food is experienced differently depending on the context. It is not clear whether context effects on food experiences are independent of the effects of specific foods. E.g., are all foods experienced more positive in a nice sushi restaurant or only the foods that have strong associations (congruent) with this context, such as sushi? A previous study with recreated beach and sushi restaurant contexts, demonstrated no effect of congruency on liking of the tasted foods. To verify whether the lack of congruency effects was caused by the relatively insensitivity of explicit response measures such as liking, implicit (facial expressions) and explicit (scores) measures of food-evoked and general emotions were used in the same study and those results are reported here.Thirty-five participants were exposed repeatedly in seven sessions in one of two recreated contexts (sushi restaurant and beach) to foods that were either congruent (sushi in the sushi restaurant, popsicle at the beach, and iced tea) or incongruent (sushi at the beach and popsicle in the sushi restaurant) with the recreated context. Contexts were switched in an eighth and final session. Facial expressions and self-reported food-evoked emotions showed significant effects of context and foods (p < 0.05). General and food-evoked self-reported emotions were closely related, and showed systematic changes over repeated exposure, immersive context and food. No effect of food-context congruency was found, i.e., effects of contexts and foods on self-reported food-evoked emotions and facial expressions were independent. Food-evoked emotions were more positively valenced in the beach context compared to the restaurant context irrespective of foods (p < 0.05). After repeated exposure, self-reported emotions of boredom were intensified and those of interest were reduced, irrespective of food and context. A subsequent switch to a different context did not produce additional effects on emotions. Facial expressions also varied independently with food and context but were not affected by repeated exposure and were affected by the switch to a different context.In conclusion, the results show that 1) physical and social consumption contexts that are recreated in the laboratory affect general and food-evoked emotions measured by self-reported emotions and facial expressions, 2) foods and contexts affect food-evoked self-reported emotions and facial expressions independently , and 3) results of self-reported food-evoked emotions and facial expressions showed similarities but also differences pointing to the added value of measuring facial expressions.

Prior research using immersive technology has shown that consumption contexts can be successfully recreated to elicit effects on hedonic food evaluations, but the food-specificity of these effects is as of yet unclear. The current study investigates how repeated exposure to foods in congruent and incongruent immersive contexts affects hedonic perception over time. Two groups of participants (N = 23, N = 18) were exposed to three food products (sushi, popsicle and iced tea) in either an immersive beach context or an immersive sushi restaurant context for seven days. On the eighth day, participants were exposed to the same foods once more, but switched to the other context. Hedonic evaluations were collected prior to and during tasting at initial exposure (day 1), after repeated exposure to the same context (day 7) and in the switched context (day 8); consumption behavior was monitored on exposure days (days 2–6). Results showed that prior to tasting, expected liking and desire to eat were higher for congruent food-context combinations (popsicle at the beach, sushi in the sushi restaurant) than for incongruent combinations (popsicle in the sushi restaurant, sushi at the beach). Upon tasting, no differences were found in average food liking, but individual liking ratings for congruent (vs. incongruent) food-context combinations were more consistent over time. Immersive contexts also elicited general effects, such that a typical consumption environment (sushi restaurant) increased food consumption and yielded more consistent product liking ratings over time. Findings underline the importance of taking a holistic view on consumer testing, and showcase the potential of immersive technology.

Initial research indicates that the use of immersive technologies may improve the predictive validity and reliability of liking scores in consumer testing. However, how immersive technologies impact Just-About-Right ratings is hardly known. Forty-five participants took part in three tasting sessions, each in a different context: 1) laboratory, 2) immersive context simulating a café using audiovisual cues, and 3) real café. Each session, participants tasted four tomato soups varying in salt content preceded by a warm-up sample. Liking, optimal levels of sensory attributes (JAR) and engagement were measured. Results showed that there were no differences in liking or JAR ratings on sensory attributes of the soups across the three contexts. Nevertheless, participants felt more engaged in the real café and simulated café than in the laboratory. These results contribute to a better understanding of how sensory differences as assessed in a laboratory or immersive context relate to sensory differences that consumers would notice when they use the products in real-life.

International audience; Background: Real-life human eating behaviour does not take place in a vacuum, rather it happens in context. The context in which consumers eat their foods influences the acceptance of the consumed foods. Consequently, consumers' hedonic and sensory ratings elicited in a natural consumption context will differ from those elicited under controlled sensory laboratory conditions. Moreover, foods are rarely consumed on one single occasion but are typically consumed repeatedly and ratings may change over repeated consumptions as well. Often, consumer acceptance is tested explicitly, for example with liking ratings, especially when the testing is done outside the laboratory. Implicit tests such as facial expressions and physiological measurements of the autonomic nervous system can provide additional information on consumer acceptance. As a result of technological advantages, such tests are no longer limited to the laboratory but can also be used in natural consumption contexts. Method: Eighteen healthy Dutch consumers (18–65 years of age) tested four test foods plus a warm-up sample ten times on consecutive weekdays and on similar hours using their own laptop and webcam. Test locations alternated between the sensory laboratory and the participant's own home. Explicit measures included liking scores and scores on ten sensory taste/flavour/texture attributes, and implicit measures included facial expressions, heart rate and consumption duration using Face ReaderTM. This study was the first to validate the Face ReaderTM for usage at home. Results: The liking scores and sensory profiles varied between test foods (p < 0.05), but not between test locations and only some specific sensory attributes showed systematic variation over repeated consumption. In contrast, implicit measures showed systematic effects of test foods, test locations, and repeated consumptions (p < 0.05). Compared to consumption in the laboratory, consumption at home was faster, triggered higher heart rates, and triggered more intense facial expressions of happiness, contempt, disgust and boredom. Conclusions: Implicit tests were more sensitive to effects of test location and repeated consumption than explicit tests. Additional research is required to investigate the relevance of these measures to long term consumer acceptance of food products.

Background Flowers are reported to have immediate and long-term effects on health and well-being, emotional reactions, mood, social behaviour and memory, but emotional effects have rarely been studied in more detail. Methods This study investigated the influences of flowers on emotional perception of others in healthy adults (n = 64), divided over 4 conditions (3 flower arrays and a flowerless control). The test included a projection test judging pictures of people. One week later memory regarding pictures in the projection test, roommates and the room they had been in, was tested. Results Flowers, positively affected peoples’ mood and their perception of others. With flowers, pictures of other people were judged more positively and less negatively than without flowers. Odorous flowers had a more negative effect. The people in the pictures seemed a bit more open, but clearly less friendly, more arrogant and more depressed under its influence. Furthermore, flowers had a positive influence on the remembrance of the room the participants had been in. Conclusion Flowers exert a more positive influence by their visual appearance than by their odour, and act more on people’s feelings towards unknown others than on liking of the food they eat, whereas flowers have little impact on remembering eating situation aspects. Practical implication The use of flowers might perhaps be recommended for increasing relaxation and mutual understanding in public places (restaurants (non-odorous flowers), meeting rooms and waiting rooms).

Recent research suggests that non-attentively perceived odours may significantly influence people’s food choices. This study’s aim was to examine the effects of different types of non-attentively perceived food odours, namely, bread odour and cucumber odour, on subsequent lunch choices in a real-life setting. The study was conducted using a within-participant design (n = 37, age 21–55 years). Participants took part in three sessions: two priming conditions (bread and cucumber odour) and one control condition (no odour). During each session, participants started by answering a questionnaire for20 min, in a room in which they were exposed to one of the odour conditions. The questionnaire functioned as a ‘lure’ task. Subsequently, participants were guided to the restaurant where they could choose lunch from a buffet. Besides lunch choice, sociodemographic factors, personality traits, and eating behaviour factors were assessed. Odour priming and control conditions did not affect lunch selections (χ2 (2, N = 37) = 28.1, p = 0.46). Self-reported positive mood was significantly affected by odour condition (F (2, 72) = 3.26, p = 0.044). In conclusion, odour condition did affect mood but not lunch choice. It is therefore questionable whether an odour prime can be used as a nudge to contribute to healthy food choice behaviour.

Evaluative conditioning may be an important mechanism for learning food preferences and aversions; however, in both real life and experimental settings it has not been consistently successful. The current study aimed to gain more insight into which underlying factors may contribute to a successful outcome of olfactory evaluative conditioning. Two groups of 18 participants came in on three consecutive days, and were repeatedly exposed to four novel, neutral odors (CS) coupled to varying disliked, neutral, liked, or no stimuli (taste and/or pictures, US), following a 50% reinforcement schedule, leading to 40 odor presentations per session. Liking ratings, as well as changes in the autonomic nervous system were assessed before, during and after conditioning. We were able to induce negative, but not positive, affective changes by pairing neutral odors with tastes and pictures differing in valence. Negative as well as multimodal stimuli appear to be more potent US, since they may be considered more salient. Lastly, results of the current study imply that heart rate is responsive to changes in valence of olfactory stimuli, and perhaps even more sensitive than explicit ratings of liking.

indexation en cours; Habituation, or decreased behavioral response, to odors is created by repeated exposure and several detailed characteristics, whereas adaptation relates to the neural processes that constitute this decrease in a behavioral response. As with all senses, the olfactory system continually encounters an enormous variety of odorants which is why mechanisms must exist to segment them and respond to changes. Although most olfactory habitation studies have focused on animal models, this non-systematic review provides an overview of olfactory habituation and adaptation in humans, and techniques that have been used to measure them. Thus far, psychophysics in combination with modern techniques of neural measurement indicate that habituation to odors, or decrease of intensity, is relatively fast with adaptation occurring more quickly at higher cerebral processes than peripheral adaptation. Similarly, it has been demonstrated that many of the characteristics of habitation apply to human olfaction; yet, evidence for some characteristics such as potentiation of habituation or habituation of dishabituation need more support. Additionally, standard experimental designs should be used to minimize variance across studies, and more research is needed to define peripheral-cerebral feedback loops involved in decreased responsiveness to environmental stimuli.

Food coatings that remain after swallowing starch-based or CMC-based custard desserts were investigated for 19 subjects. Foods were orally processed for 5 s using a pre-defined protocol, after which the food was swallowed. The remaining food coating was assessed sensorially as well as instrumentally using turbidity of rinse water. The instrumental and sensory results indicated a gradual decline of food coatings over intervals up to 180-270 s. Decline rates of coatings of individual subjects related significantly to their decline rates in perceived fattiness. Decline rates were somewhat faster for the starch-based custards indicating a role of salivary amylase in clearance of starch-based foods. No evidence was found for mechanical clearance with tongue movements. In stead, decline rates of coating after swallowing were primarily determined by oral movements before swallowing, whereby intense oral movements produced relatively little oral coatings and relatively slow decline rates, and vice versa. © 2008 Elsevier Ltd. All rights reserved.

Two studies investigated the effect of a food's viscosity on bite size, bite effort and food intake using a standardized protocol in which subjects sipped through a straw every 20 s for a period of 15 min from one of two products, a chocolate-flavored dairy drink and a chocolate-flavored dairy semi-solid, matched for energy density. In the first study, subjects consumed 47% more from the liquid than from the semi-solid to reach the same degree of satiation, with larger bite sizes for the liquid throughout the 15 minute period (8.7 ± 0.45 g) compared to the semi-solid (5.8 ± 0.3 g, p < 0.01). In the second study bite effort was eliminated by using a peristaltic pump to present the products every 20 s. Oral processing time before swallowing was set at 5 s (both products) or 8 s (semi-solid). With the elimination of bite effort and a standardized oral processing time, subjects consumed as much from the semi-solid as from the liquid to reach the same degree of satiation. Bite size for liquids started relatively small and grew gradually over successive bites, whereas the bite size for the semi-solid food started relatively large and became gradually smaller. The latter effect was even more pronounced when the oral processing time was increased from 5 to 8 s. In conclusion, semi-solids resulted in smaller bite sizes and lower intake than liquids, but these differences disappeared when differences in bite effort were eliminated. © 2008 Elsevier Inc. All rights reserved.

Background:Energy-yielding liquids elicit weak suppressive appetite responses and weak compensatory responses, suggesting that liquid calories might lead to a positive energy balance. However, data is often derived from foods differing in many characteristics other than viscosity.Objective:To investigate the effect of viscosity on ad libitum food intake in real-life setting and to investigate whether a difference in ad libitum intake is related to eating rate and/or eating effort.Design:In real-life setting 108 nonrestrained subjects (26+/-7 years, BMI 22.7+/-2.4 kg m(-2)) received a chocolate flavored liquid, semi-liquid and semi-solid milk-based product, similar in palatability, macronutrient composition and energy density. In laboratory setting 49 nonrestrained subjects (24+/-6 years, BMI 22.2+/-2.3 kg m(-2)) received the liquid or semi-solid product. Effort and eating rate were controlled by means of a peristaltic pump.Results:In real-life setting the intake of the liquid (809+/-396 g) was respectively 14 and 30% higher compared to the semi-liquid (699+/-391 g) and semi-solid product (566+/-311 g; P

Perceived fattiness and creaminess plus other texture and flavor attributes were assessed for a group of vanilla custard desserts, white sauces, and mayonnaises that differed widely in ingredients, fat content (0-72%), and consumption temperatures. In addition, the foods were measured instrumentally with regard to their lubricative properties, infra-red reflectance and turbidity of rinse water. Despite the variety in foods, fat content showed strong correlations with the instrumental measures, and perceived fattiness, and weaker but still significant correlations with creamy mouth and after-feel. Friction and infra-red reflectance demonstrated that properties of the surface of the oral food bolus are important for fat-related attributes via mechanisms such as lubrication. Turbidity of rinse water suggested that properties of the bulk of the food bolus are important as well. Creamy after-feel related less well to instrumental measures, fat content and other sensory attributes suggesting that the creaminess of oral coatings is not only affected by fat but also by other unknown properties. © 2006 Elsevier Ltd. All rights reserved.

The creation of a sensory descriptive panel for dry crusted, ‘crispy’ and ‘crunchy’ food products is presented. A sensory vocabulary comprising appearance, odour, taste, texture and sound is developed and the panel is trained to use these attributes. Model deep-fried battered snack and baked bread food products are used in the experiments with this panel. Special attention is given to ageing of the model products, and the effects this has on the sensory perception. The separation of the sensory assessment in a ‘first bite’ and a ‘during chewing’ phase turns out to be useful for this type of products, as does the inclusion of sound attributes. The vocabulary allowed both the effect of ageing and the differences between model products to be investigated in considerable detail.

Texture perception of foods has been demonstrated to be influenced by age, dental health and oral processing behaviour. Eating duration is a significant factor contributing to and determining food oral processing behaviour. The influence of eating duration on dynamic texture perception, oral processing behaviour and properties of the food bolus have not been investigated extensively. The aims of this study are (i) to determine the influence of naturally preferred eating duration on dynamic texture perception of sausages and (ii) to explain differences in dynamic texture perception between short and long duration eaters by chewing behaviour and bolus properties. Two groups of subjects were selected based on their natural eating duration for a controlled portion size of two sausages. The group of “long duration eaters” (n = 11) took on average twice as long to consume a piece of sausage compared to the group of “short duration eaters” (n = 12). Independent of eating duration, short and long eating duration subjects chewed sausages with the same chewing frequency (p = 0.57) and muscle effort rate (p = 0.15) during oral processing. Total muscle effort and total number of chews were significantly higher (p

Results of sensory, physiological and physico-chemical studies from our laboratory on perceived creaminess of semi-solids foods are reviewed. Most results stem from studies using model vanilla custard desserts, allowing systematic variation of fat, flavor and thickener properties. The generalizability of the custard results was verified for yogurts, mayonnaises, white sauces and other semi-solid foods. Creaminess sensations could be decomposed into sensations reflecting either properties of the bulk or of the surface of the oral food bolus. Bulk properties related to the rheological properties of the bolus whereas surface properties related to lubrication and flavor release. Creaminess was inversely related to enzymatic and mechanical induced break-down during oral processing. Starch thickeners generally enhanced creaminess although they suffered from enzymatic break-down compared to non-starch thickeners. It is suggested that the negative effects of break-down were off-set by positive effects of fat migrating to the surface of the bolus. The surfaced fat enhances lubrication and the release of fat-soluble flavors enhance creaminess, especially in low fat starch-based semi-solids. Bulk-related properties were measured by rheological measurements, surface-related properties were measured by friction, and mechanical- and enzymatic break-down properties were measured with a modified rheometer. © 2006 Elsevier Ltd. All rights reserved.

Summary After a mouthful of food has been swallowed, some food material is always retained in the mouth. With semi-solid foods this is in the form of a coating that adheres to the oral mucosa. The amount and location of this material may play an important role in food sensations. In this study two quantitative methods of describing the coatings, generated by a set of 16 model custards varying in degree of lubrication (fat content) and degree of viscosity (starch concentration) are investigated. In the first method, a trained quantitative descriptive analysis panel ( N = 8) was instructed to take single mouthfuls of semi-solid foods, swallow and then rinse twice for 5 s with water and spit out. The turbidity of the rinse water was then measured. During the same session, sensory assessments of the products were obtained. In the second method the thickness of the coating on the anterior and middle one-thirds of the tongue was quantified using a pair of opto-electronic reflectance sensors mounted on a probe which was placed on the tongue, one sensor measuring the anterior part of the tongue the other the posterior (middle third) of the tongue. Turbidity of the first rinse related strongly to the food's viscosity, as well as to sensory attributes associated with the food's fat content and viscosity, such as perceived thickness, creaminess and fattiness. Turbidity of subsequent rinses related primarily to fat content. These results indicate that turbidity of rinse water is a useful tool in fundamental (e.g., food texture research) as well as applied research (e.g., product development and quality assurance in food industry). Reflectance varied primarily with fat content and did not relate well to sensory attributes.

The effects of nonoral sensations, such as visual texture and odor, on the size of the first bite were investigated in a series of studies using specially constructed food delivery cups with lower, from which custards were ingested ("ingested custard"), and upper, from which a custard was viewed and/or smelled ("upper custard") compartments. Ingested and upper custards were either the same or different. Bite size was defined as the weight of custard sucked out of the lower compartment during a single suck through an I I -mm diameter straw. The results from the first study indicated that the recognition of oral qualities of custards via vision or olfaction determined the size of the first bite. When this recognition was favorable, e.g., when the upper custard was known to be creamy, a relatively large bite was taken, irrespective of the custard that was actually ingested. When this recognition was unfavorable, a relatively small bite was taken. The second study showed that when recognition was prevented by modifications of the upper custard's color, odor, or visual texture, bite size was determined by the oral qualities of the ingested custard. This was confirmed in a third study, where the oral characteristics of the ingested custard were varied by adding a flavorant (benzaldehyde) and/or by using nose clips to eliminate retronasal smelling. Bite sizes decreased significantly when these variations reduced creaminess. Odor and visual texture characteristics of the upper custard significantly affected the perception of creaminess and other attributes related to the food's viscosity, melting, and thickness. (C) 2004 Elsevier Inc. All rights reserved.

Texture and mouthfeel sensations of three groups of semisolid foodstuffs (mayonnaises and dressings, custard desserts and warm sauces) were characterised, measured, evaluated and compared based on quantitative descriptive sensory analysis of commercial products. Six groups of texture attributes were generated and used by the sensory panel. These were related to: viscosity, surface feel, bulk homogeneity, adhesion/cohesion, wetness-dryness and fat. Two groups of nontextural mouthfeel attributes were found to be relevant, which were related to perceived temperature and oral irritation. The importance of the attributes for each product category is discussed.

Background Bread choice • The average number of consumed bread rolls was 4.2 (SD=1.9). • White bread rolls were favourite: the first chosen bread roll was usually white (89%) regardless of size of offered rolls. 81% of total bread consumption was white. • Children ate more bread in grams when white rolls were larger-sized (Ps

The study explored how subjects from childhood (8–14 years old) to elderly adulthood could identify the odors of 17 everyday products. Performance at naming followed an inverted U-shaped course over age, best in young adults and poorest in children and elderly. A discrimination task given to the adults revealed parallel age-related declines in ability to name and to discriminate odors. Correct identification by edibility exceeded that by name considerably. For dangerous household products, children achieved only 15% correct naming but 79% correct edibility/inedibility. Scenting of dangerous household products, however, may compromise the discriminability of these products from less harmful ones. "Fresh" -scented hypochlorite bleach yielded significantly more errors regarding its possible causticity than did unscented bleach. Such modifications of products would seem to necessitate other compensatory changes to enhance discriminability and thereby maintain safety.

Olfactory-evoked potentials (OEPs) were recorded monopolarly at the Fz, Cz and Pz electrode sites in young adults and elderly subjects with an amyl acetate stimulus presented olfactometrically. Psychophysical odor thresholds for amyl acetate were determined using a two-alternative, forced-choice detection procedure. These demonstrated a decreased odor detection sensitivity in the elderly relative to tye young subjects. In accordance with the threshold findings, elderly subjects produced significantly smaller N1 and P2 amplitudes, and a trend towards longer latencies than younger subjects. Moreover, odor threshold was found to correlate with amplitude magnitude. The OEP findings, which are discussed in the context of previous OEP studies, offer promise as an objective, non-invasive measure of sensory function in both clinical and non-clinical settings.

Frictional conditions in the mouth are thought by food scientists to be critical to the perception of important food attributes such as astringency, smoothness, roughness, slipperiness, etc. This ability to detect friction probably evolved to avoid foods that could wear the teeth excessively. In modern humans, sensations related to friction and lubrication affect consumer responses to food products and are therefore commercially important. In this study, the coefficient of friction between two mucosal surfaces was measured using stimulated and unstimulated saliva at loads varying from 0.34 to 2.20 N and at speeds varying from 0.1 to 700 mm s-1. The coefficient of friction decreased with increasing load and speed for both types of saliva. Lubrication with stimulated saliva resulted in higher friction than with unstimulated saliva. Stimulated saliva has a higher protein content and lower viscosity than unstimulated saliva, which may explain the friction differences found between the two types of saliva. The reduction in friction with load is attributed to deformation of the mucosal surfaces, leading to a reduction in surface roughness. © 2006.

The intra-oral processing of semi-solids foods is dominated by effects due to tongue movement. These movements subject the food to shear forces and mix it with saliva. Both actions tend to reduce the viscosity of the products. These changes are perceived as "melting" by sensory panellists. In a previous study where subjects were trained to use a variety of intra-oral manipulation it was shown that the amount of tongue movement was an important factor in determining the sensory experience of the products. The goal of this study was to develop a system which could measure changes in viscosity due to temperature, shear, dilution and structure breakdown, monitor the rate of and extent of mixing, mimic the pattern of mixing extant in the mouth. Simulation requires that shear forces, mixing and thermal effects be mimicked faithfully. To compare samples recovered from the mouth with those mixed in the simulator we compare the amount of mixing as measured using an image-processing technique. The simulator allows the effects of shear, dilution, and α-amylase concentration on the rheology and heterogeneity of the product to be monitored in real time. By way of example the effects of dilution, shear and chemical breakdown are compared in a starch-based semi-solid food. © 2006.

In this study a diabetic glucose monitor was used to measure the glucose content of 40 model vanilla custard desserts, these were compared with sensory ratings from a trained quantitative descriptive analysis panel. Stimuli varied in starch type, concentration and homogenisation but had identical sugar, flavour and fat contents. Despite this, mean sensory ratings of sweetness varied from 21 to 43 on a 100-point scale. Glucose levels in the stimuli were measured, in vitro, before and after the addition of 0.1% whole human saliva to the product. In all cases glucose concentration increased after the addition of saliva as starch was converted to glucose. There were highly significant correlations of some odour, flavour, mouth feel and after-feel attributes with glucose concentration. The correlation of sweet flavour with glucose concentration was higher in unmodified stimuli than in stimuli with added saliva, suggesting that sweetness is perceived soon after ingestion. Additional glucose produced through starch breakdown appeared to have a relatively small impact on the sensory scores of the stimuli.

It has been generally assumed that fat is detected by its flavour and by its lubrication of the oral mucosa. A recent study reported a correlation of -.99 between perceived temperature of a product and its fat content. This was significantly higher than correlations of sensory scores for fat flavour, mouthfeel, and afterfeel. This suggested a third detection mechanism; fat may be detected via its effect on the thermal conductivity of the food. In 3 studies, thermal sensitivity in humans was investigated to verify whether oral thermal receptors are sufficiently rapid and accurate to play a role in the perception of fats. The thermal sensitivity of the lips and oral mucosa of the anterior and middle one-third of the tongue were assessed using a Peltier device. Subjects detected 0.5 Hz fluctuations in temperature of 0.08°C on the lower lip, 0.26°C and 1.36°C at the tip and dorsum of the tongue, demonstrating that the lips are sufficiently sensitive to detect small differences in temperature. In two further experiments subjects ingested custards and mayonnaises and then spat out samples after 5, 10, or 20 sec. The temperature of the food and oral mucosa was measured before and after spitting and the rates of heating were calculated. Results suggest assessment of thermal conductivity of food may be used to assess fat content. © Perceptual and Motor Skills 2007. Chemicals / CAS: Dietary Fats

Sensitivity to 6-n-propylthiouracil (PROP) for a group of 180 naïve consumers was related to their perception of 16 commercially available vanilla custard desserts. Rated intensities of taste and texture attributes varied moderately and inconsistently with PROP sensitivity. In contrast, discriminative ability increased with PROP sensitivity resulting in higher numbers of significant differences between pairs of custards. In terms of signal/noise theory, the results indicate that PROP sensitivity enhances the separation of the response signals but does not reduce their noise. The naïve consumers were also compared with highly trained panelists to test whether effects of PROP sensitivity resemble the effects of experience and training. Naïve consumers and trained panelists responded similarly with respect to taste and texture sensations such as creaminess and thickness, but were clearly different with respect to others such as heterogeneity and fattiness. Trained panelists demonstrated even stronger discriminative abilities than consumers with high PROP sensitivities for some attributes but weaker abilities for others. A practical implication of these findings is that selection criteria for participation in sensory panels should include PROP sensitivity, if the panel is aimed at maximum discriminative performance. © 2006 Elsevier Ltd. All rights reserved.

A number of in vitro and in vivo instrumental tests have been developed to reflect various aspects of the perceived oral texture of starch-based vanilla custard desserts. These tests include measurements of the food's infra-red reflectance (IRR), of the turbidity of spat-out rinse water, and of the friction between the food and the oral tissue. Also, images of spat-out foods have been digitally processed and image-processing parameters extracted. These tests, together with conventional rheological tests, were carried out on a set of vanilla custard desserts that varied systematically with respect to fat content (0-15%), starch content (3.3-5.1%), and type of modified starch (potato, tapioca, and waxy maize starch with various degrees of cross-liking) judged by nine highly trained QDA panelists. Three sensory dimensions could be identified from principal component analysis to summarize the sensory texture space of the custards. The results from instrumental measurements, together with the effects of ingredients, indicated that the fist dimension, running from roughness to creaminess, was related to lubrication. The second dimension, running from melting to thickness, was related to stimulus viscosity. Finally, the third dimension, running from airy to heterogeneous, was related to starch type. The results indicate that each sensory dimension has attributes that are either related to surface properties or to bulk properties of the food bolus and that saliva - and starch break-down by salivary amylase - should be incorporated into instrumental measurements. Key sensory attributes from all three dimensions were predicted well from instrumental measurements. © 2005 Elsevier Ltd. All rights reserved.

The sensory components of creamy mouthfeel in commercial mayonnaises, custard desserts and sauces were determined, using multi-variate analysis of the mean sensory ratings obtained from a quantitative descriptive analysis (QDA) panel. Creamy is a particularly interesting attribute, as it is generally well correlated with consumer preference. Texture attributes which were found to contribute positively to creamy mouthfeel included thick, airy, smooth and fatty mouth- or afterfeel, negative contributions were found for rough, heterogeneous, grainy and melting mouth- or afterfeel. Odour (assessed before ingestion) and non-texture trigeminal attributes had little or no effect on creamy mouthfeel, taste/flavour attributes (assessed while the product is in the mouth) did affect creamy mouthfeel, in some cases positively (caramel flavour) and in some cases negatively (broth and cheese flavour). The use of noseclips or the addition of a flavouring substance, confirmed that olfactory cues and/or intranasal sensations have an effect on creamy mouthfeel. © 2004 Elsevier Ltd. All rights reserved.

The influence of bite size on sensory mouthfeel and afterfeel sensations was explored in two studies in which single bites of vanilla custard desserts were varied from 2 to 11 mL (study 1) and in which series of five bites of two different custard desserts were presented consecutively (study 2). In single bites, sensations of perceived creaminess were enhanced with size whereas sensations of astringency and temperature were suppressed. Bite size also affected perceived thickness, but the direction of the effects varied with custard desserts. With multiple bites, creaminess sensations continued to increase, whereas other sensations were unaffected. Switching to a second series of bites of another vanilla custard dessert showed larger sensory effects, especially on astringency sensations but also to a lesser extent on sensations of thickness and fatty afterfeel. Single and multiple bite results are discussed in terms of possible peripheral mechanisms. Switching results are discussed in terms of possible central sensory contrast mechanisms.

Emotional responses to foods at various product consumption stages, e.g. purchase, usage and consumption, are gaining increasing attention because of their potential to add to liking ratings in predicting consumers’ food choice. The aim of this study was to investigate whether packaging information alters emotional profiles elicited by intrinsic food properties (unlabelled products) and how this relates to food choice. Participants (N = 103) tasted seven test products, scored liking, and evaluated each product on evoked emotions using the EsSense Profile Method™ in two conditions (unlabelled and labelled product presentation). The seven test products were a selection of five commercially available breakfast drinks and two dairy products that matched the breakfast drinks in taste, texture etc. but are marketed as dessert products. In two (unlabelled and labelled condition) separate breakfast sessions, we assessed actual food choice, where participants chose their preferred food product out of seven. Analysis of Variance for each product separately showed that EsSense™ could differentiate between emotions evoked by the two conditions. Specifically, emotions associated with the unlabelled product were generally more intense (5-point scale) than emotions measured in the labelled condition. Notably, the few emotions which scored higher in the labelled compared to the unlabelled condition represent the ‘activation’ dimension, e.g. energetic and adventurous. Comparing the two actual food choice sessions we observed a shift in choice towards consumption-context ‘appropriate’ products in the labelled condition. Hence, breakfast drinks were chosen more often when presented labelled whereas ‘inappropriate’ dessert-products were chosen less.

Consumer food choice and intake are largely controlled by unconscious processes, which may be reflected better by implicit physiological and behavioural measures than by the more traditional explicit sensory tests. In this study, 26 human participants were exposed to an orange (pleasant) and a fish (unpleasant) odour presented in three different concentrations perceived as weak, medium and strong intensity, and five replications in a semi-random order via an olfactometer (Burghart OM2). Reactions to these odours were measured implicitly by means of facial expressions (automatically analysed with FaceReader), skin conductance responses and heart rate frequency (automatically analysed by Biolab), and explicitly with pleasantness ratings. Facial expressions reflected the odour’s valence (71% explained variance) and ranged from neutral (orange) to sadness/disgust/anger (fish) but showed additional differentiation with respect to odour intensity (15% explained variance). Skin conductance responses were largest for the unpleasant odour ( p p p

Energy-yielding liquids seem to elicit weak satiety responses and weak compensatory responses in energy intake, suggesting that liquid calories might lead to a positive energy balance. However, data is often derived from foods differing in many characteristics other than viscosity. We investigated the effect of viscosity on ad libitum food intake (study 1) and underlying mechanisms (study 2). Chocolate-flavoured liquid, semi-liquid and semi-solid milk-based products were used, equal in palatability, macronutrient composition and energy density. In study 1 the ad libitum intake in a natural setting in 108 non-restrained adults (BMI 22.7±2.4 kg/m2) was determined. The intake of the liquid was 14% and 30% higher compared to the semi-liquid and semi-solid product (P

Energy-yielding liquids seem to elicit weak satiety responses. However, data is often derived from foods differing in many characteristics other than viscosity. We investigated the effect of viscosity on ad libitum food intake (study 1) and underlying mechanisms (study 2,3). A chocolate-flavored liquid and semi-solid test product were used, equal in palatability, macronutrient composition and energy density. In study 1 the ad libitum intake in natural setting was determined in 108 non-restrained adults (BMI 22.7±2.4 kg/m2). Intake of the liquid was 30% higher than the semi-solid product (P

A model description of intensity perception in human taste and smell developed earlier has now been verified experimentally to determine parameter values for odorants. The final objective is to quantify and understand odour-odour interaction phenomena in e.g., masking, deo-perfumes and flavour enhancement. Five types of olfactometer experiments were carried out, viz. determination of thresholds, determination of reaction times, scaling of perceived intensity after 5 sec stimulation, scaling of perceived intensity of a fixed concentration at variable duration, and measurement of intensity/time relationships. Four subjects were used and the odorants cineole, geraniol and hexane.

Subjects rated the overall perceived intensity of concentrations of the odorants cineole, geraniol, hexyl salicylate, and linalyl acetate smelled alone and in binary mixtures. The subjects also rated intensity of specified constituents (e.g. amount of cineole in cineole, and in mixtures of cineole and linalyl acetate). The intensity of the stronger component alone offered a close description of perceived intensity. In addition to the Stronger Component model, two other psychological models (Vector and U model) and two psychophysical models (UPL2 and Equiratio Mixture model) offered descriptions ranging from fair to very good. Psychological models gave better fits, but lack explanatory power. Some results indicated that weaker odors add more potently than stronger odors, an outcome incompatible with these models. The psychophysical models, based on the additivity of single components, generally overestimated perceived intensity. Judgments of individual qualities gave only slight encouragement to any expectation of differences in masking or maskability among odorants. The results highlight the need to test particular critical hypotheses regarding how people perceive mixtures.