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Bayesian networks were used to combine raw datasets from two independently performed but related studies. Both studies investigated sensory satiation by measuring ad libitum intake of a tomato soup model. The Aroma study varied aroma concentration and aroma duration as the explanatory variables, and the Taste study varied salt intensity. To combine the data from the two studies, the Aroma study needed information on salt aspects for all of its observations. Equally, the Taste study needed information on aroma aspects. This information was used to link the two single networks, each representing one study, into a combined network; therefore, it is referred to as structural linking information. The approach taken is seen as an example for the potential benefit and the challenges when combining raw datasets from different studies. The combined network is able to generate additional insights into complex relationships encountered with research on satiation. The main challenge results from the missing of structural linking information. In this paper, we (1) suggest solutions for obtaining the structural linking information, and (2) propose an approach to global experimental design to prevent this situation. The nature of the paper is theoretical rather than analytical due to the limitations caused by the small size of datasets.

Background: The modern food supply is often dominated by a large variety of energy dense, softly textured foods that can be eaten quickly. Previous studies suggest that particular oral processing characteristics such as large bite size and lack of chewing activity contribute to the low satiating efficiency of these foods. To better design meals that promote greater feelings of satiation, we need an accurate picture of the oral processing characteristics of a range of solid food items that could be used to replace softer textures during a normal hot meal. Aim: The primary aim of this study was to establish an accurate picture of the oral processing characteristics of a set of solid savoury meal components. The secondary aim was to determine the associations between oral processing characteristics, food composition, sensory properties, and expected satiation. Methods: In a within subjects design, 15 subjects consumed 50 g of 35 different savoury food items over 5 sessions. The 35 foods represented various staples, vegetables and protein rich foods such a meat and fish. Subjects were video-recorded during consumption and measures included observed number of bites, number of chews, number of swallows and derived measures such as chewing rate, eating rate, bite size, and oral exposure time. Subjects rated expected satiation for a standard 200 g portion of each food using a 100 mm and the sensory differences between foods were quantified using descriptive analysis with a trained sensory panel. Statistical analysis focussed on the oral processing characteristics and associations between nutritional, sensory and expected satiation parameters of each food. Results: Average number of chews for 50 g of food varied from 27 for mashed potatoes to 488 for tortilla chips. Oral exposure time was highly correlated with the total number of chews, and varied from 27 s for canned tomatoes to 350 s for tortilla chips. Chewing rate was relatively constant with an overall average chewing rate of approximately 1 chew/s. Differences in oral processing were not correlated with any macronutrients specifically. Expected satiation was positively related to protein and the sensory attributes chewiness and saltiness. Foods that consumed in smaller bites, were chewed more and for longer and expected to impart a higher satiation. Discussion: This study shows a large and reliable variation in oral exposure time, number of required chews before swallowing and expected satiation across a wide variety of foods. We conclude that bite size and oral-sensory exposure time could contribute to higher satiation within a meal for equal calories.

The main reason for recreational use of cannabis is the 'high', the primary psychotropic effect of D 9 -tetrahydrocannabinol (THC). This psychoactive compound of cannabis induces a range of subjective, physical and mental reactions. The effect on heart rate is pronounced and complicates bloodflow-based neuroimaging of psychotropic effects of THC. In this study we investigated the effects of THC on baseline brain perfusion and activity in association with the induction of 'feeling high'. Twenty-three subjects participated in a pharmacological MRI study, where we applied arterial spin labelling (ASL) to measure perfusion, and resting-state functional MRI to assess blood oxygen level-dependent signal fluctuation as a measure of baseline brain activity. Feeling high was assessed with a visual analogue scale and was compared to the imaging measures. THC increased perfusion in the anterior cingulate cortex, superior frontal cortex, and insula, and reduced perfusion in the post-central and occipital gyrus. Baseline brain activity was altered, indicated by increased amplitude of fluctuations in resting-state functional MRI signal after THC administration in the insula, substantia nigra and cerebellum. Perfusion changes in frontal cortex were negatively correlated with ratings of feeling high, suggesting an interaction between cognitive control and subjective effects of THC. In conclusion, an acute THC challenge altered baseline brain perfusion and activity, especially in frontal brain areas involved in cognitive and emotional processes, and the insula, associated with interoceptive awareness. These changes may represent the THC-induced neurophysiological correlates of feeling high. The alterations in baseline brain perfusion and activity also have relevance for studies on task-related effects of THC on brain function.

Little is known about the influence of visual characteristics other than colour on flavor perception, and the complex interactions between more than two sensory modalities. This study focused on the effects of recognizability of visual (texture) information on flavor perception of odorized sweet beverages. Participants rated the perceived sweetness of odorized sucrose solutions in the presence or absence of either a congruent or incongruent visual context. Odors were qualitatively reminiscent of sweet foods (strawberry and caramel) or not (savoury). Visual context was either an image of the same sweet foods (figurative context) or a visual texture derived from this product (non-figurative context). Textures were created using a texture synthesis method that preserved perceived food qualities while removing object information. Odor-taste combinations were rated sweeter within a figurative than a non-figurative context. This behaviour was exhibited for all odor-taste combinations, even in trials without images, indicating sustained priming by figurative visual context. A non-figurative context showed a transient sweetening effect. Sweetness was generally enhanced most by the strawberry odor. We conclude that the degree of recognizability of visual information (figurative versus non-figurative), influences flavor perception differently. Our results suggest that this visual context priming is mediated by separate sustained and transient processes that are differently evoked by figurative and non-figurative visual contexts. These components operate independent of the congruency of the image-odor-taste combinations.

New meat substitutes need to be recognized as alternatives to meat. We therefore investigated which category representations consumers have of meat and meat substitutes. Thirty-four non-vegetarian participants performed a free sorting task with 17 meat products and 19 commercially available meat substitutes, followed by similarity and typicality ratings. Results indicated that categorization was largely influenced by the taxonomic classification of meat, so by categories that refer to the animal source like 'pork', 'beef' etc. Hence, meat substitutes were grouped separately from non-processed meat products. However, there were categories (e.g. 'pieces' and 'sausages') that contained both meat substitutes and processed meat products, as these products were perceived to be very similar.New meat substitutes should have a certain resemblance to meat in order to replace meat on the plate. This can be achieved by either similarity in appearance or by referring to shared scripts/goals, such as a similar application in meals. Refereed/Peer-reviewed

In their short communication against satiety claims, Booth and Nouwen (2010) neglect dozens of well designed studies that show consistent relations between satiety, energy intake and body weight. Satiety, intake and weight are separate concepts, that need different claims and evidence to support them. Satiety can be measured reliably. A repeated higher satiety response to a specific food compared to an appropriate control food may be valuable to consumers who want to avoid hunger. This is good for society. The development of the psycho-biological knowledge to achieve this is good for science. The lawmaker should provide the frame of reference for trustworthy satiety claims. It is then up to the consumer to decide the value of these claims.

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The reduction of salt and sugar in food products remains a challenge due to the importance of those ingredients in providing a highly desired taste quality, enhancing flavor, determining the behavior of structuring ingredients, and ensuring microbiological safety. Several technologies have been used to reduce salt and sugar content in foods such as replacement of sugar by sweeteners, replacement of sodium salts by blends of other salts, taste enhancement by aromas and taste boosters or gradual reduction of sugar and salt in small steps over time. In this study we present two alternative approaches to enhance taste perception. First, the use of an inhomogeneous spatial distribution of sugar in food gels is introduced as a way to enhance sweetness perception [1]. The translation of the concept of taste contrast to bread applications is discussed which allows to reduce salt content in bread by 25% without loss of saltiness intensity and without addition of taste enhancers, aromas or salt replacers [2]. Secondly, it is demonstrated how the serum release under compression of mixed polysaccharide/protein gels can be engineered to enhance sweetness perception. An increase of serum release by 5x allowed to reduce sugar content of gels by 30% while maintaining sweet taste intensity [3]. The translation of this concept to low salt sausages is discussed. Sausages were engineered to exhibit enhanced juiciness which lead to a boost of saltiness allowing for up to 40% salt reduction [4]. These approaches can be used to further optimize the development of products with reduced salt and sugar content while maintaining taste intensity.

Objectives - Decreased energy intake in older persons poses these people at risk of progressive weight loss. It may result from a failure to regulate energy intake and expenditure after periods of underfeeding. The objective of this study was to investigate if a period of underfeeding differentially influences energy intake of older compared with young men and, additionally, to study potential underlying mechanisms, namely changes in gastric emptying rate and cholecystokinin (CCK) levels in blood. Design/setting - Dietary intervention of 3 phases. After a phase of energy balance, we fed participants in phase 2 by a mean of 70% of their needs for 21 days. During phase 3, we assessed ad libitum energy intake of the participants during 9 days. At the end of phases 1 and 2, we assessed appetite, gastric emptying, and CCK levels in blood in response to a test meal. Participants - Fifteen young (age 24 years [range 20–34], body mass index 23.0 kg/m2 ± 2.3) and 17 older (age 68 years [64–85], body mass index 24.5 kg/m2 ± 1.9) men participated in this study. Results - During energy balance, mean energy intake of young men (14.3 ± 2.3 MJ/day) was significantly higher than that of older men (11.3 ± 1.8 MJ/day, P

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In view of the increasing numbers in overweight and obesity, insight in food intake regulation is necessary. Food intake is regulated by sensory, cognitive, post-ingestive, and post-absorptive processes. Food properties, such as energy density, macronutrient composition, volume, and form, influence the satiating capacity of a food. This chapter focuses on the role of food texture in food intake regulation. Texture is an essential part of the whole spectrum of sensory properties of a food. Several studies showed that liquid foods elicit weaker suppressive appetite responses and a weaker compensatory response in energy intake than solid or semisolid foods. The mechanisms underlying the effect of texture on satiety are not well understood. Beverages might engage thirst mechanisms and not hunger mechanisms. Food properties such as viscosity and texture could affect chewing, oro-gastric handling of foods, and absorption. Other factors that play a role are beliefs about the satiating capacity of a food, sensory specific satiety, eating rate, gastric emptying, and learned associations between texture and metabolic consequences. One of the mechanisms involved could be the oral sensory exposure time. A longer oral exposure time gives the sensory receptors in the oral cavity more time to respond to the food. Liquid calories facilitate energy intake. This knowledge can be useful in both the overweight and underweight situation.

In the light of increasing rates of nutrition related diseases, such as obesity, diabetes, high blood pressure and stroke it is necessary to reduce sugar, salt and fat contents of industrial produced food. Reduction of those components generally leads to changes of the sensory properties of the products and rejection by the consumer. Traditional compensation strategies like the use of taste enhancers, artificial sweeteners or fat replacers often lead to off-flavours and consequently to consumer rejection. This thesis describes cross-modal interactions as an alternative strategy to reduce sugar, salt and fat. In the past cross-modal interactions have been describe to influence taste and texture perception, however up to now research focused on simple model systems lacking in perceptual, as well as chemical complexity. This thesis aimed on the application of cross modal interactions involving aroma modification to complex food systems, such as apple juice and cheese. It was investigated whether aromas are able to modify taste perception in complex food matrices and what the driving factors are to which extend aromas can enhance taste perception. Furthermore different cross modal approaches were combined in order to investigate possible additive or synergistic effects on taste enhancement. At first, the question whether individual aroma components can be identified that have the capacity to enhance taste perception in a complex beverage was addressed [chapter 2]. Apple juice was choosen to represent a complex matrix where interactions between taste and aroma are a natural product characteristic. Ethylhexanoate was identified to significantly enhance sweetness in apple juice, while three other esters selected on the same basis did not show sweetness enhancement. Ethylhexanoate induced sweetness enhancement appeared to be concentration dependent. Concentrations of 5 ppm were found to be most effective to enhance sweetness in this specific system. However, next to sweetness undesired attributes such as flowery and synthetic were also increased significantly. As a conclusion it has to be noticed that flavour balance in complex food is fragile and has to be carefully altered in order to use odour induced taste enhancement as a tool in sugar, salt and fat reduction. Chapter 3 describes the masking of off-flavours induced by ethylhexanoate as described in chapter 2. It was hypothesised that ethylhexanoate induced off-flavours can be masked by restoring flavour balance by equally adding combinations of all four esters. A combination of ethylhexanoate, ethylbutanoate and ethyl-2-methylbutanoate was found to be most effective to restore flavour quality while maintaining ethylhexanoate induced sweetness enhancement. It was concluded that all components that are naturally part of an aroma are needed to achieve a balanced product. Optimisation of odour presentation time in order to achieve maximum taste enhancement was subject to the study described in chapter 4. Swallowing is the key to aroma release during food consumption. It was demonstrated that aroma is most presented most effectively either 1.7 – 2.5 seconds before or 2.6 – 3.6 seconds after the moment of swallow. Aroma presented directly at the moment of swallow was found to be least effective to enhance taste. It is assumed that olfactory receptor neurons (ORN) do not transmit the activation signal to the brain at the exact moment of swallow in order to spare energy and function most effective, as during normal food consumption the aroma is released shortly after swallowing. This hypothesis was further tested in an fMRI study. Preliminary results support this theory, however at the moment of completion of this thesis data evaluation was still in progress. In chapter 5 further optimisation of odour/taste interactions was studied, by investigating the influence of temperature on odour induced taste enhancement. Consumption temperatures differ strongly among products. As aroma release strongly depends on the temperature of the food, it was hypothesised that the magnitude of aroma effects on taste perception changes over consumption temperature. Subjects consumed a sweet and a savoury system at four different temperatures (7, 25, 37 and 50°C). Stimuli temperature and odour presentation were fully controlled by temperature optimised gustometry and olfactometry. Both aroma/taste systems were known to have induced taste enhancement in the past (sweet: apple flavoured tea/ethylhexanoate; savoury: broth/sotolon). No significant effect of temperature was found for either of the stimulus pairs. Results indicate that the complexity of the experiment led to confusion by the panelists under fully randomised stimuli delivery conditions. It was therefore concluded, that temperature effects on the magnitude of odour induced taste enhancement need to be studied in a reduced experimental design. Temporal contrast as a strategy to enhance salty taste was studied in the experiments described in chapter 6. Salty solutions of different NaCl concentrations were presented in alternating sequence by a gustometer, creating a sensory contrast of low-in salt and high-in salt pulses. It was demonstrated that the sensory contrast induced by the pulsed delivery led to significant taste enhancement. It was shown that high concentrations of NaCl delivered in short pulses were most effective to enhance salty taste. It was concluded that pulsed stimulus delivery can be an additional tool to reduce salt and sugar concentrations in industrial produced food. Chapter 7 combines both cross-modal strategies to enhance taste in this thesis so far, odour induced taste enhancement and temporal contrast of stimulus delivery. Subjects were presented with taste and aroma pulses timed via a gustometer. The aroma was either presented in-phase or out-of-phase with the taste stimulus. A cumulative effect of aroma/taste interactions and temporal contrast of tastant delivery was found, resulting in higher taste enhancement than each of the strategies alone. Overall highest sweetness enhancement was observed when aroma and taste pulses were presented out-of-phase. Texture modification is a third cross-modal strategy to enhance taste perception. Combinatory effects of texture modification and odour induced taste enhancement are subject to the study reported in chapter 8. Apple juice containing gels were engineered differing in textural properties, aroma and sugar concentration. In contrast to the results presented in chapter 7, only an additive but no synergistic effect was found for those strategies. Texture modification was found to be more effective than aroma modification. Chapter 9 studies effects of aroma on the taste and the texture of cheese and dairy model gels. In the first study subjects consumed different types of cheese with and without a nose-clip. This way the contribution of the aroma phase on the flavour and texture perception of cheese was studied. Saltiness was influenced significantly by the aroma. It was concluded that the aroma of cheese strongly contributes to a cheeses salty taste. Furthermore it was observed that a decrease in cheese firmness strongly correlated with an increase in buttery aroma notes. This was further studied in fully controlled dairy model gels. For gels tasting of cream cheese a significant decrease in firmness was found upon increasing aroma concentration. No effect of butter aroma on firmness was found for yoghurt-like gels. This once more demonstrates the importance of congruency between stimuli. Only congruent sensory impressions can influence each other. In addition, an increase in creaminess was observed with increasing aroma concentration. The results described in chapter 9 clearly show that aromas cannot only modify taste perception, but also are a valid tool for texture modification. This thesis demonstrates for the first time, that flavour and texture modification and subsequently the reduction of sugar, salt and (possibly also) fat can be achieved by using cross modal interactions in complex food matrices. New methods have been developed and existing methods have been combined to study aroma/taste interactions in fully controlled settings. Its multidisciplinary approach combines chemical, physical and psychological knowledge in order to discuss and explain results. It furthermore shows that combinations of different strategies are most effective in order to achieve healthier products reduced in sugar, salt and fat.

It is posed that protein intake is tightly regulated by the human body. The role of sensory qualities in the satiating effects of protein, however, requires further clarification. Our objective was to determine the effect of within-meal protein content and taste on subsequent food choice and satiety. We used a cross-over design whereby sixty healthy, unrestrained subjects (twenty-three males and thirty-seven females) with a mean age of 20·8 (sd 2·1) years and a mean BMI of 21·5 (sd 1·6) kg/m2 were offered one of four isoenergetic preloads (rice meal) for lunch: two low in protein (about 7 % energy derived from protein) and two high in protein (about 25 % energy from protein). Both had a sweet and savoury version. At 30 min after preload consumption, subjects were offered an ad libitum buffet, consisting of food products differing in protein content (low/high) and taste (sweet/savoury). In addition, the computerised Leeds Food Preference Questionnaire (LFPQ) was run to assess several components of food reward. The results showed no effect of protein content of the preloads on subsequent food choice. There was an effect of taste; after eating the savoury preloads, choice and intake of sweet products were higher than of savoury products. No such preference was seen after the sweet preloads. No differences in satiety were observed. To conclude, within one eating episode, within-meal protein content in these quantities seems not to have an effect on subsequent food choice. This appears to be mostly determined by taste, whereby savoury taste exerts the strongest modulating effect. The results of the LFPQ provided insight into underlying processes.

Dietary fibres are believed to reduce subjective appetite, energy intake and body weight. However, different types of dietary fibre may affect these outcomes differently. The aim of this review was to systematically investigate the available literature on the relationship between dietary fibre types, appetite, acute and long-term energy intake, and body weight. Fibres were grouped according to chemical structure and physicochemical properties (viscosity, solubility and fermentability). Effect rates were calculated as the proportion of all fibre–control comparisons that reduced appetite (n = 58 comparisons), acute energy intake (n = 26), long-term energy intake (n = 38) or body weight (n = 66). For appetite, acute energy intake, long-term energy intake and body weight, there were clear differences in effect rates depending on chemical structure. Interestingly, fibres characterized as being more viscous (e.g. pectins, ß-glucans and guar gum) reduced appetite more often than those less viscous fibres (59% vs. 14%), which also applied to acute energy intake (69% vs. 30%). Overall, effects on energy intake and body weight were relatively small, and distinct dose–response relationships were not observed. Short- and long-term effects of dietary fibres appear to differ and multiple mechanisms relating to their different physicochemical properties seem to interplay. This warrants further exploration.

Our knowledge regarding the neural processing of the three chemical senses has been considerably lagging behind that of our other senses. It is only during the last 25 years that significant advances have been made in our understanding of where in the human brain odors, tastants, and trigeminal stimuli are processed. Here, we provide an overview of the current knowledge of how the human brain processes chemical stimuli based on findings in neuroimaging studies using positron emission tomography and functional magnetic resonance imaging. Additionally, we provide new insights from recent meta-analyses, on the basis of all published neuroimaging studies of the chemical senses, of where the chemical senses converge in the brain.

In the light of increasing rates of nutrition related diseases, such as obesity, diabetes, high blood pressure and stroke it is necessary to reduce sugar, salt and fat contents of industrial produced food. Reduction of those components generally leads to changes of the sensory properties of the products and rejection by the consumer. Traditional compensation strategies like the use of taste enhancers, artificial sweeteners or fat replacers often lead to off-flavours and consequently to consumer rejection. This thesis describes cross-modal interactions as an alternative strategy to reduce sugar, salt and fat. In the past cross-modal interactions have been describe to influence taste and texture perception, however up to now research focused on simple model systems lacking in perceptual, as well as chemical complexity. This thesis aimed on the application of cross modal interactions involving aroma modification to complex food systems, such as apple juice and cheese. It was investigated whether aromas are able to modify taste perception in complex food matrices and what the driving factors are to which extend aromas can enhance taste perception. Furthermore different cross modal approaches were combined in order to investigate possible additive or synergistic effects on taste enhancement. At first, the question whether individual aroma components can be identified that have the capacity to enhance taste perception in a complex beverage was addressed [chapter 2]. Apple juice was choosen to represent a complex matrix where interactions between taste and aroma are a natural product characteristic. Ethylhexanoate was identified to significantly enhance sweetness in apple juice, while three other esters selected on the same basis did not show sweetness enhancement. Ethylhexanoate induced sweetness enhancement appeared to be concentration dependent. Concentrations of 5 ppm were found to be most effective to enhance sweetness in this specific system. However, next to sweetness undesired attributes such as flowery and synthetic were also increased significantly. As a conclusion it has to be noticed that flavour balance in complex food is fragile and has to be carefully altered in order to use odour induced taste enhancement as a tool in sugar, salt and fat reduction. Chapter 3 describes the masking of off-flavours induced by ethylhexanoate as described in chapter 2. It was hypothesised that ethylhexanoate induced off-flavours can be masked by restoring flavour balance by equally adding combinations of all four esters. A combination of ethylhexanoate, ethylbutanoate and ethyl-2-methylbutanoate was found to be most effective to restore flavour quality while maintaining ethylhexanoate induced sweetness enhancement. It was concluded that all components that are naturally part of an aroma are needed to achieve a balanced product. Optimisation of odour presentation time in order to achieve maximum taste enhancement was subject to the study described in chapter 4. Swallowing is the key to aroma release during food consumption. It was demonstrated that aroma is most presented most effectively either 1.7 – 2.5 seconds before or 2.6 – 3.6 seconds after the moment of swallow. Aroma presented directly at the moment of swallow was found to be least effective to enhance taste. It is assumed that olfactory receptor neurons (ORN) do not transmit the activation signal to the brain at the exact moment of swallow in order to spare energy and function most effective, as during normal food consumption the aroma is released shortly after swallowing. This hypothesis was further tested in an fMRI study. Preliminary results support this theory, however at the moment of completion of this thesis data evaluation was still in progress. In chapter 5 further optimisation of odour/taste interactions was studied, by investigating the influence of temperature on odour induced taste enhancement. Consumption temperatures differ strongly among products. As aroma release strongly depends on the temperature of the food, it was hypothesised that the magnitude of aroma effects on taste perception changes over consumption temperature. Subjects consumed a sweet and a savoury system at four different temperatures (7, 25, 37 and 50°C). Stimuli temperature and odour presentation were fully controlled by temperature optimised gustometry and olfactometry. Both aroma/taste systems were known to have induced taste enhancement in the past (sweet: apple flavoured tea/ethylhexanoate; savoury: broth/sotolon). No significant effect of temperature was found for either of the stimulus pairs. Results indicate that the complexity of the experiment led to confusion by the panelists under fully randomised stimuli delivery conditions. It was therefore concluded, that temperature effects on the magnitude of odour induced taste enhancement need to be studied in a reduced experimental design. Temporal contrast as a strategy to enhance salty taste was studied in the experiments described in chapter 6. Salty solutions of different NaCl concentrations were presented in alternating sequence by a gustometer, creating a sensory contrast of low-in salt and high-in salt pulses. It was demonstrated that the sensory contrast induced by the pulsed delivery led to significant taste enhancement. It was shown that high concentrations of NaCl delivered in short pulses were most effective to enhance salty taste. It was concluded that pulsed stimulus delivery can be an additional tool to reduce salt and sugar concentrations in industrial produced food. Chapter 7 combines both cross-modal strategies to enhance taste in this thesis so far, odour induced taste enhancement and temporal contrast of stimulus delivery. Subjects were presented with taste and aroma pulses timed via a gustometer. The aroma was either presented in-phase or out-of-phase with the taste stimulus. A cumulative effect of aroma/taste interactions and temporal contrast of tastant delivery was found, resulting in higher taste enhancement than each of the strategies alone. Overall highest sweetness enhancement was observed when aroma and taste pulses were presented out-of-phase. Texture modification is a third cross-modal strategy to enhance taste perception. Combinatory effects of texture modification and odour induced taste enhancement are subject to the study reported in chapter 8. Apple juice containing gels were engineered differing in textural properties, aroma and sugar concentration. In contrast to the results presented in chapter 7, only an additive but no synergistic effect was found for those strategies. Texture modification was found to be more effective than aroma modification. Chapter 9 studies effects of aroma on the taste and the texture of cheese and dairy model gels. In the first study subjects consumed different types of cheese with and without a nose-clip. This way the contribution of the aroma phase on the flavour and texture perception of cheese was studied. Saltiness was influenced significantly by the aroma. It was concluded that the aroma of cheese strongly contributes to a cheeses salty taste. Furthermore it was observed that a decrease in cheese firmness strongly correlated with an increase in buttery aroma notes. This was further studied in fully controlled dairy model gels. For gels tasting of cream cheese a significant decrease in firmness was found upon increasing aroma concentration. No effect of butter aroma on firmness was found for yoghurt-like gels. This once more demonstrates the importance of congruency between stimuli. Only congruent sensory impressions can influence each other. In addition, an increase in creaminess was observed with increasing aroma concentration. The results described in chapter 9 clearly show that aromas cannot only modify taste perception, but also are a valid tool for texture modification. This thesis demonstrates for the first time, that flavour and texture modification and subsequently the reduction of sugar, salt and (possibly also) fat can be achieved by using cross modal interactions in complex food matrices. New methods have been developed and existing methods have been combined to study aroma/taste interactions in fully controlled settings. Its multidisciplinary approach combines chemical, physical and psychological knowledge in order to discuss and explain results. It furthermore shows that combinations of different strategies are most effective in order to achieve healthier products reduced in sugar, salt and fat.

What does it take to increase the consumption of meat substitutes and attract new consumers? We identified main barriers and drivers by a consumer survey (n= 553) in the U.K. and the Netherlands. Person-related factors (food neophobia and food choice motives) and product-related attitudes and beliefs towards meat and meat substitutes were compared between non-users (n= 324), light/medium-users (n= 133) and heavy-users of meat substitutes (n= 96). Consumer acceptance was largely determined by the attitudes and beliefs towards meat substitutes and food neophobia. Key barriers for non-users and light/medium-users were the unfamiliarity with meat substitutes and the lower sensory attractiveness compared to meat. In addition, non-users had a higher tendency to avoid new foods. Hence, the less consumers were using meat substitutes, the more they wanted these products to be similar to meat. Although non-users and light/medium-users did recognize the ethical and weight-control aspects of meat substitutes, this was obviously less relevant to them. Actually, only heavy-users had high motivations to choose ethical foods, which explains their choice for meat substitutes. In order to make meat substitutes more attractive to meat consumers, we would not recommend to focus on communication of ethical arguments, but to significantly improve the sensory quality and resemblance to meat Refereed/Peer-reviewed

BACKGROUND: Olfactory and gustatory functions have not been well characterized in older adults in the US. Consequently, their relationships to sociodemographic characteristics, as well as physical and mental health, were studied in a large national probability sample using brief validated tests of chemosensory function. METHODS: A five-odour identification test and taste-impregnated strips of filter paper (sweet, sour, bitter, and salty) assessed the ability to identify chemosensory stimuli. RESULTS: Severe gustatory dysfunction was more prevalent than severe olfactory dysfunction. Age, education and sex were independently associated with performance on both the olfactory and gustatory identification tasks. Higher scores were associated with female sex, higher level of education, and lower age. Odour identification scores exhibited a positive, albeit weak, correlation with BMI, and food-related odours were better identified than non-food odours. In addition, odour identification performance was also negatively associated with depressive symptoms. CONCLUSIONS: These data demonstrate a high prevalence of severe gustatory and, to a somewhat lesser extent, olfactory dysfunction in a population-based sample and demonstrate that even brief tests are capable of detecting correlations between both chemical senses and relevant health measures outside a clinical setting.

Eating rate and bite size are important factors affecting food intake, and we hypothesise the underlying role of oral sensory exposure in this. However, the latter currently lacks objective measuring parameters, but an interesting measure could be the extent ofin vivoretro-nasal aroma release. Second, the literature is ambiguous about overweight subjects differing from normal-weight subjects in eating behaviour. Consequently, we investigated: (1) whether eating behaviour (food intake, eating rate, bite size, number of bites and meal duration) relates to weight status and (2) whether the extent of retro-nasal aroma release relates to eating behaviour and weight status. A matched group (sex, age and dietary restraint) of twenty-seven normal-weight (BMI 21·8 (sd1·6) kg/m2) and twenty-seven overweight/obese subjects (BMI 30·5 (sd5·8) kg/m2) consumed a spiced rice meal and apple pie yogurt on separate test days. The extent of retro-nasal aroma release was measured on a third test day. Mean bite size for spiced rice was significantly (P = 0·03) larger in overweight/obese (10·3 (sd3·2) g)v.normal-weight subjects (8·7 (sd2·1) g). There were no other significant differences in eating behaviour or retro-nasal aroma release between the groups. Eating behaviours were not correlated with BMI or retro-nasal aroma release. Subjects showed consistent eating behaviour for both test products. Eating behaviour might be a characteristic of an individual but not by definition a characteristic for a group of people based on their weight. Given the large sample sizes, necessary according toa posteriorisample size calculations, one needs to consider the relevance of finding a statistically significant difference in eating behaviour between the weight groups in a laboratory setting.

Background Despite the health benefits, children’s fruit and vegetable intake is below that recommended. This thesis focuses on the role of parental strategies, children’s cognitive development and properties of food in order to develop new approaches to increase fruit and vegetable preferences and intake in 4 to 12-year-old children. Methods First, we conducted a qualitative study (N=28) with three age groups representing different cognitive developmental stages, and a parental survey study (N=242). These studies indicated that texture was more important for 4-5-year-old children’s food preferences than for 11-12-year olds and that the parental strategy of ‘Choice’ was positively related to both children’s fruit and vegetable intake. Subsequently, in three intervention studies, the focus was on vegetables only, because previous approaches have been less effective for vegetable intake than for fruit intake. We investigated three approaches for their effectiveness in increasing children’s vegetable acceptance: 1. Varying the preparation method (4-12y; N=94): Carrots and French beans were prepared in six ways: mashed, boiled, steamed, grilled, stir-fried and deep-fried. 2. Flavour-nutrient learning (7-8y; N=19): During a 14-day learning period, vegetable flavours were combined with energy (maltodextrin) or without energy in a drink. 3. Choice-offering (4-6y; N=303): Children had no choice, a choice before a meal, or a choice during a meal regarding which vegetable out of two they were going to eat. Results Varying the preparation method demonstrated that steamed and boiled were preferred over the other preparations (p

The aim of this paper is to describe and discuss relevant aspects of the assessment of physiological functions - and related biomarkers - implicated in the regulation of appetite in humans. A short introduction provides the background and the present state of biomarker research as related to satiety and appetite. The main focus of the paper is on the gastrointestinal tract and its functions and biomarkers related to appetite for which sufficient data are available in human studies. The first section describes how gastric emptying, stomach distension and gut motility influence appetite; the second part describes how selected gastrointestinal peptides are involved in the control of satiety and appetite (ghrelin, cholecystokinin, glucagon-like peptide, peptide tyrosin-tyrosin) and can be used as potential biomarkers. For both sections, methodological aspects (adequacy, accuracy and limitation of the methods) are described. The last section focuses on new developments in techniques and methods for the assessment of physiological targets involved in appetite regulation (including brain imaging, interesting new experimental approaches, targets and markers). The conclusion estimates the relevance of selected biomarkers as representative markers of appetite regulation, in view of the current state of the art.

This study explored the effect of texture differences on satiation (ad libitum food intake) in 3 pairs of solid foods. Test products were specially developed luncheon meat, meat replacers and sweets. Each food consisted of a " hard" and " soft" version, expected to lead to different eating rates and consequently to differences in oral sensory exposure time. One hundred and six subjects participated in 7 sessions. During the first sessions, subjects consumed the products ad libitum while watching a movie in a cinema. During the last session, eating rate of all products was measured. Mean intake did not differ significantly between the hard and soft version for any of the products, but subjects who ate more of the soft luncheon meat significantly outnumbered subjects who ate more of the hard version. Eating rate was significantly slower for the hard than for the soft luncheon meat (21 ± 10 vs. 25 ± 13. g/min); no differences were found for the other food types. Ad libitum intake was twice as high in the highest versus the lowest quartile of eating rate (p

This study aimed to investigate how different preparation methods influence children’s liking for vegetables. Participants were children from three age groups (4–6 years N = 46; 7–8 years N = 25; 11–12 years N = 23) and young adults (18–25 years N = 22). The participants tasted and ranked six preparation methods for carrots and French beans: mashed, steamed, boiled, stir-fried, grilled and deep-fried. In addition, the different vegetable preparations were rated on 15 attributes. All participants preferred boiled and steamed vegetables over the other preparations (p < 0.05). Boiled and stir-fried were the most familiar preparation methods for both vegetables. Vegetable liking was positively related to a uniform surface and the typical vegetable taste, and moderately related to crunchiness, whereas brown colouring and a granular texture were negatively related to vegetable liking. On the basis of these results, we conclude that children’s vegetable liking is influenced by a complex mixture of a uniform appearance, easily controllable textures and a typical, familiar vegetable taste.

In humans little is known as to whether oral sensory stimulation with alcohol elicits cephalic phase responses. This study sought to determine whether oral alcohol exposure, in the form of white wine, provokes cephalic phase responses in normal-weight and overweight women. In a semi-randomized, crossover trial, eleven normal-weight and eleven overweight women sham-fed, after an overnight fast under three separate conditions 4 weeks apart, cake (750. kJ), 25. cL white wine (750. kJ; ∼26. g alcohol) and 25. cL water. Blood was drawn prior to and for 30. min after two 3-min episodes of modified sham-feeding (MSF). Blood samples were analyzed for free fatty acid (FFA), triglyceride, glucose, pancreatic polypeptide (PP), insulin and alcohol concentrations. Incremental area under the curves (IAUC) of FFA concentrations differed significantly between the three treatments but not between BMI categories. After MSF with wine, FFA concentrations dropped to a minimum of 77 ± 3% of baseline concentrations at t=12 ± 2. min after baseline and returned to baseline after ∼30. min, whereas after MSF with cake and water, FFA concentrations gradually increased. In conclusion, short-term oral white wine exposure substantially and temporarily decreases FFA concentrations suggesting a cephalic phase response of alcohol. This effect occurred regardless of BMI. © 2010 Elsevier Ltd.

The invention provides a method for the production of a flour-based food product comprising a tastant. The food product according to the invention has a tastant bulk weight percentage and an inhomogeneous tastant bulk distribution. The invention provides the use of an inhomogeneous tastant bulk distribution in a food product for providing a food product with a reduced tastant bulk weight percentage. Further, the invention provides the use of an inhomogeneous tastant bulk distribution in a food product for enhancing and/or improving the sensory perception of the tastant in a food product.

Background: An important question in the regulation of energy intake is whether dietary learning of energy content depends on the food's characteristics, such as texture. Texture might affect the duration of sensory exposure and eating rate. Objective: The objective was to investigate whether a long sensory exposure, due to differences in means of consumption and in viscosity, enhances learned associations between sensory signals and metabolic consequences and hence facilitates energy intake compensation. Design: A total of 105 healthy young adults with a mean (±SD) age of 22 ± 3 y and a body mass index (in kg/m2) of 21.6 ± 1.7 participated in a parallel intervention in 3 groups: liquid yogurt with a straw (liquid/straw; n = 34), liquid yogurt with a spoon (liquid/ spoon; n = 36), or semisolid yogurt with a spoon (semisolid/spoon; n = 35). Novel flavored yogurts were offered ad libitum for breakfast in 2 energy densities: low (≈215 kJ/100 g) and high (≈600 kJ/ 100 g). Subjects were repeatedly exposed to the yogurt products (10 times), and yogurt intake was measured. Results: Intakes (P = 0.01) and eating rates (P = 0.01) were highest in the liquid/straw group. Average intakes over 10 exposures were 575 ± 260 g for liquid/straw, 475 ± 192 g for liquid/spoon, and 470 ± 223 g for semisolid/spoon; average eating rates were 132 ± 83 g/min for liquid/straw, 106 ± 53 g/min for liquid/spoon, and 105 ± 88 g/min for semisolid/spoon. No significant interaction for intake between intervention group, energy density, and repeated exposure was observed, and intakes of the low- and high-energy-dense yogurts did not change over time in any of the intervention groups. Conclusions: We observed no energy intake compensation after repeated exposure to yogurt products. Differences in ad libitum yogurt intake could be explained by eating rate, which was affected by the different means of consumption. This trial was registered with the Dutch trial registration at http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1853 as NTR1853. © 2010 American Society for Nutrition.

This paper describes the effect of serum release on sweetness intensity in mixed whey protein isolate/gellan gum gels. The impact of gellan gum and sugar concentration on microstructure, permeability, serum release and large deformation properties of the gels was determined. With increasing gellan gum concentration the size of the pores present in the protein network, the permeability and the serum release increased, as well as the Young's modulus, the fracture stress and the fracture strain. Increasing the sugar concentration induced an increase of the pore size, but resulted in a decrease of permeability and serum release. The addition of sugar resulted in gels with a higher Young's modulus and a lower fracture strain. This effect was more evident at higher gellan gum concentrations. By changing the protein concentration of the gels, a set of samples was prepared exhibiting constant large deformation properties but varying in serum release and sugar concentration. Serum release significantly boosted sweetness intensity. For example, the sweetness scores for gels with 12% serum release were the same as for gels with 2% serum release but 30% higher sugar concentration. The results indicate that serum release is a tool to compensate for the loss taste intensity related to the reduction of sugar and salt in gelled foods.

Background and objective: In view of the growing epidemic of obesity, it is important to investigate factors which influence food intake. Food texture has been shown to play a role in food intake regulation but underlying explaining mechanisms are unknown. The aim of this thesis was to determine the effect of food texture on satiation (assessed as ad libitum food intake) and to investigate the mediating role of oral sensory exposure and gastro-intestinal physiology in this effect. Methods: We started by investigating the effect of food viscosity on ad libitum food intake (n=108). Next, we investigated whether the effect of viscosity could be related to eating effort and/or eating rate (n=49) or to the release of the gastro-intestinal hormones ghrelin, CCK and GLP-1 (n=33). To further explore the role of oral sensory exposure, we investigated the effect of changing bite size and oral processing time of a semi-solid food on satiation (n=22), and the effect of changing food texture of three pairs of solid foods on satiation (n=106). Finally, we observed eating behavior and retro-nasal aroma release in normal weight and overweight subjects (n=54). Results: Viscosity of food had a clear effect on food intake; increasing viscosity significantly decreased ad libitum food intake and the difference in intake between the liquid and semi-solid product ranged from 29% to 34% in different settings. Eating rate played an important role; the liquid product was consumed significantly faster than the semi-solid product and a standardized eating rate led to similar intakes of these products. The selected gastro-intestinal hormones could not explain the effect of viscosity on food intake; a fixed amount of the liquid and semi-solid test product resulted in a similar response of the hormones. Food intake of a semi-solid food was significantly less when oral processing time was fixed to 9 s compared to 3 s (on average a difference of 42 g) and when consumed with fixed small bite sizes (≈ 5 g) compared to large bite sizes (≈ 15 g) (on average a difference of 106 g). Differences in food texture of solid foods, aimed to change oral processing time, did not affect food intake. Texture differences were probably too subtle to lead to differences in eating rate and subsequently to differences in food intake. Significant positive associations between food intake and eating behaviors such as eating rate and bite size were observed. Small to no differences in eating behavior and retro-nasal aroma release were found between normal weight and overweight subjects. Conclusion: The results of this thesis show that food viscosity has a direct effect on food intake. Oral sensory exposure plays a major role in this since changing eating rate, oral processing time and bite size affected food intake. These factors contribute to the effect of food texture on food intake. In addition, eating rate and bite size were characteristics of the eating style of an individual.

Bread and cereals contribute 30% to the daily intake of sodium (Na) in the western human diet. Since the average Na intake is double the recommended intake, pressure has built up for the food industry to lower Na in their products. Especially replacing functionality of Na as a tastant remains very difficult. In this study we describe a strategy to enhance saltiness intensity in bread using an inhomogeneous spatial distribution of Na. Our results demonstrate that sensory contrast provides a promising strategy to significantly reduce the Na content in bread without loss of saltiness intensity and without the use of sodium substitutes, taste or aroma additives. © 2010 Elsevier Ltd.

Background Despite the health benefits, children’s fruit and vegetable intake is below that recommended. This thesis focuses on the role of parental strategies, children’s cognitive development and properties of food in order to develop new approaches to increase fruit and vegetable preferences and intake in 4 to 12-year-old children. Methods First, we conducted a qualitative study (N=28) with three age groups representing different cognitive developmental stages, and a parental survey study (N=242). These studies indicated that texture was more important for 4-5-year-old children’s food preferences than for 11-12-year olds and that the parental strategy of ‘Choice’ was positively related to both children’s fruit and vegetable intake. Subsequently, in three intervention studies, the focus was on vegetables only, because previous approaches have been less effective for vegetable intake than for fruit intake. We investigated three approaches for their effectiveness in increasing children’s vegetable acceptance: 1. Varying the preparation method (4-12y; N=94): Carrots and French beans were prepared in six ways: mashed, boiled, steamed, grilled, stir-fried and deep-fried. 2. Flavour-nutrient learning (7-8y; N=19): During a 14-day learning period, vegetable flavours were combined with energy (maltodextrin) or without energy in a drink. 3. Choice-offering (4-6y; N=303): Children had no choice, a choice before a meal, or a choice during a meal regarding which vegetable out of two they were going to eat. Results Varying the preparation method demonstrated that steamed and boiled were preferred over the other preparations (p

Low-caloric artificial sweeteners have been around for several decades now. Still, the debate over their usefulness in decreasing energy intake is ongoing. In principle, replacing sugar-containing foods with 'light' versions will lead to decreased energy intake. However, the reality of food intake behavior is not so simple and still many people tend to consume more calories than they burn and gain weight. Thus, 'light' products are not the easy solution they seem to be. Food intake regulation takes place in the brain. There, multiple neural and hormonal signals are integrated, ultimately leading to a particular pattern of food intake. For many years, the brain has been treated as a 'black box' in food research and other behavioral research alike. In recent years, however, functional neuroimaging techniques have enabled researchers to examine, noninvasively, the effects of different food stimuli in the human brain. This review summarizes literature on the effects of caloric and low-caloric sweeteners on physiological responses and eating behavior and specifically addresses recent neuroimaging studies. Such studies, along with others, suggest that the body cannot simply be 'fooled' by providing sweet taste without calories. Prevention of excess energy intake may not only be aided by refraining from liquid calories and other energy-dense 'fast foods', but also by a consistent relation between sweetness and caloric content. More research addressing the short as well as the long term effects of the replacement of foods and drinks by (partially) artificially sweetened 'light' versions is warranted.

Summary This report describes a set of scientific procedures used to assess the impact of foods and food ingredients on the expression of appetite (psychological and behavioural). An overarching priority has been to enable potential evaluators of health claims about foods to identify justified claims and to exclude claims that are not supported by scientific evidence for the effect cited. This priority follows precisely from the principles set down in the PASSCLAIM report. The report allows the evaluation of the strength of health claims, about the effects of foods on appetite, which can be sustained on the basis of the commonly used scientific designs and experimental procedures. The report includes different designs for assessing effects on satiation as opposed to satiety, detailed coverage of the extent to which a change in hunger can stand alone as a measure of appetite control and an extensive discussion of the statistical procedures appropriate for handling data in this field of research. Because research in this area is continually evolving, new improved methodologies may emerge over time and will need to be incorporated into the framework. One main objective of the report has been to produce guidance on good practice in carrying out appetite research, and not to set down a series of commandments that must be followed.

Meat production places a heavy burden on the environment and therefore options are sought to reduce meat consumption. One option is to let new meat substitutes take the place of meat on the plate. This can only succeed when these products are acceptable to consumers. The thesis investigated which factors are involved in consumer acceptance of meat substitutes to reduce the consumption of meat. Looking back in time, it becomes apparent that in development and acceptance of food substitutes, like margarine and sugar substitutes, different factors played a role. Technology advances and governmental policy measures could create favourable preconditions but the degree of replacement ultimately depended on consumer acceptance. This required a product quality comparable to the original products and a fit with consumer needs. The process of substitution generally takes many years, both from consumer acceptance and from product development point of view. First of all, consumers need to have a reason to choose for meat substitutes instead of meat. Therefore, drivers and barriers to use meat substitutes were identified by two surveys. Opposed to the ethical motives of heavy-users of meat substitutes (mainly vegetarians), non-users and light/medium-users were primarily focussed on the sensory and familiarity aspects of foods. These aspects were not at all recognized in meat substitutes by these consumers. Meat was judged more positively overall, which explains the choice for meat. In addition, food neophobia (the tendency to avoid new foods) was a large barrier for initial trial and a meat-like meat substitute was preferred to begin with. Secondly, the identification of a product as an alternative to meat is important. A categorization study showed that consumer perceptions are largely influenced by a deep-rooted taxonomic classification of meat (e.g. beef, pork). In order to be considered as an alternative to meat, a certain degree of similarity is needed. Meat substitutes were grouped together with processed meats (like sausages) due to a similar appearance and similar application in meals, but not with unprocessed meats. New concepts that were radically different from meat in appearance were not at all recognized as alternatives. In the third place, meat substitutes need to result in a comparable product experience as meat, such as satiety feelings after eating. The protein content is an important factor in satiety. A product inventory indicated that the majority of meat substitutes has a lower protein content than meat. In a consumption study it was shown that meat substitutes high in protein were able to induce stronger feelings of satiety, even more than the meat reference products. However, meat substitutes with a low protein content were less satiating. Finally, it should be possible to eat meat substitutes regularly without getting bored. A repeated consumption test was performed with two meat substitutes and a meat reference. It was found that initially the meat reference was liked most but after 20 exposures the difference in liking disappeared. Both boredom and increased liking of products were observed. Strikingly, there were more persons with an increased liking for the meat substitute dissimilar to meat (tofu). This is in line with the mere exposure effect implicating that unfamiliar products are liked better over time. In conclusion, meat is obviously anchored in our culinary culture and it will take time to change this. The use of substitutes introduces specific challenges due to a direct comparison and competition with meat. Meat substitutes need to offer additional benefits, which is not yet the case for the majority of consumers. At present, it seems too early for radically new protein products, since a certain level of similarity to meat is essential. Improvement of the sensory appeal of meat substitutes needs to be continued and it is worthwhile to explore other options further, like combined plant/ meat protein products. Meat production places a heavy burden on the environment and therefore options are sought to reduce meat consumption. One option is to let new meat substitutes take the place of meat on the plate. This can only succeed when these products are acceptable to consumers. The thesis investigated which factors are involved in consumer acceptance of meat substitutes to reduce the consumption of meat. Looking back in time, it becomes apparent that in development and acceptance of food substitutes, like margarine and sugar substitutes, different factors played a role. Technology advances and governmental policy measures could create favourable preconditions but the degree of replacement ultimately depended on consumer acceptance. This required a product quality comparable to the original products and a fit with consumer needs. The process of substitution generally takes many years, both from consumer acceptance and from product development point of view. First of all, consumers need to have a reason to choose for meat substitutes instead of meat. Therefore, drivers and barriers to use meat substitutes were identified by two surveys. Opposed to the ethical motives of heavy-users of meat substitutes (mainly vegetarians), non-users and light/medium-users were primarily focussed on the sensory and familiarity aspects of foods. These aspects were not at all recognized in meat substitutes by these consumers. Meat was judged more positively overall, which explains the choice for meat. In addition, food neophobia (the tendency to avoid new foods) was a large barrier for initial trial and a meat-like meat substitute was preferred to begin with. Secondly, the identification of a product as an alternative to meat is important. A categorization study showed that consumer perceptions are largely influenced by a deep-rooted taxonomic classification of meat (e.g. beef, pork). In order to be considered as an alternative to meat, a certain degree of similarity is needed. Meat substitutes were grouped together with processed meats (like sausages) due to a similar appearance and similar application in meals, but not with unprocessed meats. New concepts that were radically different from meat in appearance were not at all recognized as alternatives. In the third place, meat substitutes need to result in a comparable product experience as meat, such as satiety feelings after eating. The protein content is an important factor in satiety. A product inventory indicated that the majority of meat substitutes has a lower protein content than meat. In a consumption study it was shown that meat substitutes high in protein were able to induce stronger feelings of satiety, even more than the meat reference products. However, meat substitutes with a low protein content were less satiating. Finally, it should be possible to eat meat substitutes regularly without getting bored. A repeated consumption test was performed with two meat substitutes and a meat reference. It was found that initially the meat reference was liked most but after 20 exposures the difference in liking disappeared. Both boredom and increased liking of products were observed. Strikingly, there were more persons with an increased liking for the meat substitute dissimilar to meat (tofu). This is in line with the mere exposure effect implicating that unfamiliar products are liked better over time. In conclusion, meat is obviously anchored in our culinary culture and it will take time to change this. The use of substitutes introduces specific challenges due to a direct comparison and competition with meat. Meat substitutes need to offer additional benefits, which is not yet the case for the majority of consumers. At present, it seems too early for radically new protein products, since a certain level of similarity to meat is essential. Improvement of the sensory appeal of meat substitutes needs to be continued and it is worthwhile to explore other options further, like combined plant/ meat protein products.

Background and objective: In view of the growing epidemic of obesity, it is important to investigate factors which influence food intake. Food texture has been shown to play a role in food intake regulation but underlying explaining mechanisms are unknown. The aim of this thesis was to determine the effect of food texture on satiation (assessed as ad libitum food intake) and to investigate the mediating role of oral sensory exposure and gastro-intestinal physiology in this effect. Methods: We started by investigating the effect of food viscosity on ad libitum food intake (n=108). Next, we investigated whether the effect of viscosity could be related to eating effort and/or eating rate (n=49) or to the release of the gastro-intestinal hormones ghrelin, CCK and GLP-1 (n=33). To further explore the role of oral sensory exposure, we investigated the effect of changing bite size and oral processing time of a semi-solid food on satiation (n=22), and the effect of changing food texture of three pairs of solid foods on satiation (n=106). Finally, we observed eating behavior and retro-nasal aroma release in normal weight and overweight subjects (n=54). Results: Viscosity of food had a clear effect on food intake; increasing viscosity significantly decreased ad libitum food intake and the difference in intake between the liquid and semi-solid product ranged from 29% to 34% in different settings. Eating rate played an important role; the liquid product was consumed significantly faster than the semi-solid product and a standardized eating rate led to similar intakes of these products. The selected gastro-intestinal hormones could not explain the effect of viscosity on food intake; a fixed amount of the liquid and semi-solid test product resulted in a similar response of the hormones. Food intake of a semi-solid food was significantly less when oral processing time was fixed to 9 s compared to 3 s (on average a difference of 42 g) and when consumed with fixed small bite sizes (≈ 5 g) compared to large bite sizes (≈ 15 g) (on average a difference of 106 g). Differences in food texture of solid foods, aimed to change oral processing time, did not affect food intake. Texture differences were probably too subtle to lead to differences in eating rate and subsequently to differences in food intake. Significant positive associations between food intake and eating behaviors such as eating rate and bite size were observed. Small to no differences in eating behavior and retro-nasal aroma release were found between normal weight and overweight subjects. Conclusion: The results of this thesis show that food viscosity has a direct effect on food intake. Oral sensory exposure plays a major role in this since changing eating rate, oral processing time and bite size affected food intake. These factors contribute to the effect of food texture on food intake. In addition, eating rate and bite size were characteristics of the eating style of an individual.

The current food supply in many parts of the world differs substantially from that which existed during most of human evolution. It is characterized by a high variety of palatable foods with high energy density and low fiber content. Many foods can be eaten very quickly, and there is not always congruency between the sensory properties of the food and the subsequent metabolic consequences of its ingestion, (e.g., as in the consumption of artificially sweetened foods). It is not presently known how the human body copes with this incongruent food environment in terms of short-term satiety responses and long(er)-term regulation of food intake. Cephalic phase responses (CPRs) are innate and learned physiological responses to sensory signals that prepare the gastrointestinal tract for the optimal processing of ingested foods. CPRs could be affected by inconsistencies in the associations between sensory signals and subsequent post-ingestive consequences. Reviewed here are the available data on how CPRs affect the control of food intake

Meat production places a heavy burden on the environment and therefore options are sought to reduce meat consumption. One option is to let new meat substitutes take the place of meat on the plate. This can only succeed when these products are acceptable to consumers. The thesis investigated which factors are involved in consumer acceptance of meat substitutes to reduce the consumption of meat. Looking back in time, it becomes apparent that in development and acceptance of food substitutes, like margarine and sugar substitutes, different factors played a role. Technology advances and governmental policy measures could create favourable preconditions but the degree of replacement ultimately depended on consumer acceptance. This required a product quality comparable to the original products and a fit with consumer needs. The process of substitution generally takes many years, both from consumer acceptance and from product development point of view. First of all, consumers need to have a reason to choose for meat substitutes instead of meat. Therefore, drivers and barriers to use meat substitutes were identified by two surveys. Opposed to the ethical motives of heavy-users of meat substitutes (mainly vegetarians), non-users and light/medium-users were primarily focussed on the sensory and familiarity aspects of foods. These aspects were not at all recognized in meat substitutes by these consumers. Meat was judged more positively overall, which explains the choice for meat. In addition, food neophobia (the tendency to avoid new foods) was a large barrier for initial trial and a meat-like meat substitute was preferred to begin with. Secondly, the identification of a product as an alternative to meat is important. A categorization study showed that consumer perceptions are largely influenced by a deep-rooted taxonomic classification of meat (e.g. beef, pork). In order to be considered as an alternative to meat, a certain degree of similarity is needed. Meat substitutes were grouped together with processed meats (like sausages) due to a similar appearance and similar application in meals, but not with unprocessed meats. New concepts that were radically different from meat in appearance were not at all recognized as alternatives. In the third place, meat substitutes need to result in a comparable product experience as meat, such as satiety feelings after eating. The protein content is an important factor in satiety. A product inventory indicated that the majority of meat substitutes has a lower protein content than meat. In a consumption study it was shown that meat substitutes high in protein were able to induce stronger feelings of satiety, even more than the meat reference products. However, meat substitutes with a low protein content were less satiating. Finally, it should be possible to eat meat substitutes regularly without getting bored. A repeated consumption test was performed with two meat substitutes and a meat reference. It was found that initially the meat reference was liked most but after 20 exposures the difference in liking disappeared. Both boredom and increased liking of products were observed. Strikingly, there were more persons with an increased liking for the meat substitute dissimilar to meat (tofu). This is in line with the mere exposure effect implicating that unfamiliar products are liked better over time. In conclusion, meat is obviously anchored in our culinary culture and it will take time to change this. The use of substitutes introduces specific challenges due to a direct comparison and competition with meat. Meat substitutes need to offer additional benefits, which is not yet the case for the majority of consumers. At present, it seems too early for radically new protein products, since a certain level of similarity to meat is essential. Improvement of the sensory appeal of meat substitutes needs to be continued and it is worthwhile to explore other options further, like combined plant/ meat protein products. Meat production places a heavy burden on the environment and therefore options are sought to reduce meat consumption. One option is to let new meat substitutes take the place of meat on the plate. This can only succeed when these products are acceptable to consumers. The thesis investigated which factors are involved in consumer acceptance of meat substitutes to reduce the consumption of meat. Looking back in time, it becomes apparent that in development and acceptance of food substitutes, like margarine and sugar substitutes, different factors played a role. Technology advances and governmental policy measures could create favourable preconditions but the degree of replacement ultimately depended on consumer acceptance. This required a product quality comparable to the original products and a fit with consumer needs. The process of substitution generally takes many years, both from consumer acceptance and from product development point of view. First of all, consumers need to have a reason to choose for meat substitutes instead of meat. Therefore, drivers and barriers to use meat substitutes were identified by two surveys. Opposed to the ethical motives of heavy-users of meat substitutes (mainly vegetarians), non-users and light/medium-users were primarily focussed on the sensory and familiarity aspects of foods. These aspects were not at all recognized in meat substitutes by these consumers. Meat was judged more positively overall, which explains the choice for meat. In addition, food neophobia (the tendency to avoid new foods) was a large barrier for initial trial and a meat-like meat substitute was preferred to begin with. Secondly, the identification of a product as an alternative to meat is important. A categorization study showed that consumer perceptions are largely influenced by a deep-rooted taxonomic classification of meat (e.g. beef, pork). In order to be considered as an alternative to meat, a certain degree of similarity is needed. Meat substitutes were grouped together with processed meats (like sausages) due to a similar appearance and similar application in meals, but not with unprocessed meats. New concepts that were radically different from meat in appearance were not at all recognized as alternatives. In the third place, meat substitutes need to result in a comparable product experience as meat, such as satiety feelings after eating. The protein content is an important factor in satiety. A product inventory indicated that the majority of meat substitutes has a lower protein content than meat. In a consumption study it was shown that meat substitutes high in protein were able to induce stronger feelings of satiety, even more than the meat reference products. However, meat substitutes with a low protein content were less satiating. Finally, it should be possible to eat meat substitutes regularly without getting bored. A repeated consumption test was performed with two meat substitutes and a meat reference. It was found that initially the meat reference was liked most but after 20 exposures the difference in liking disappeared. Both boredom and increased liking of products were observed. Strikingly, there were more persons with an increased liking for the meat substitute dissimilar to meat (tofu). This is in line with the mere exposure effect implicating that unfamiliar products are liked better over time. In conclusion, meat is obviously anchored in our culinary culture and it will take time to change this. The use of substitutes introduces specific challenges due to a direct comparison and competition with meat. Meat substitutes need to offer additional benefits, which is not yet the case for the majority of consumers. At present, it seems too early for radically new protein products, since a certain level of similarity to meat is essential. Improvement of the sensory appeal of meat substitutes needs to be continued and it is worthwhile to explore other options further, like combined plant/ meat protein products.

Dissociating between ‘good’ or ‘bad’ odors is arguable of crucial value for human survival, since unpleasant odors often signal danger. Therefore, negative odors demand a faster response in order to quickly avoid or move away from negative situations. We know from other sensory systems that this effect is most evident for stimuli from ecologically-relevant categories. In the olfactory system the classification of odors into the food or non-food category is of eminent importance. We therefore aimed to explore the link between odor processing speed and accuracy and odor edibility and valence by assessing response time and detection accuracy. We observed that reaction time and detection accuracy are influenced by both pleasantness and edibility. Specifically, we showed that an unpleasant food odor is detected faster and more accurately than odors of other categories. These results suggest that the olfactory system reacts faster and more accurately to ecologically-relevant stimuli that signal a potential danger.

Mono-sodium glutamate (MSG) and/or flavors may improve palatability and intake in elderly people. Whether this improvement is related to a decline in chemosensory sensitivity is unclear. We examined the effect of flavor-enhanced tomato soup (1,200 mg/l MSG (0.12% MSG) + 3 g/l celery powder) versus non-enhanced soup on intake and liking in 120 older adults (72 +/- 6 years). Olfactory and gustatory performance was measured. For the whole group, no difference in intake (198 g vs. 203 g) (P = 0.97), liking (6.6 vs. 6.7) (P = 0.99) and strength (7.2 vs. 7.2) (P = 0.76) between the soups was found. Intake (P = 0.52), liking (P = 0.90) and strength (P = 1.00) between the soups were not different within the low olfactory/low gustatory group. Intake and liking of the flavor-enhanced soup was not increased within elderly with low chemosensory sensitivity. Enhancing flavors to increase intake and liking may not be a uniform approach due to the heterogeneity in chemosensory losses among elderly people.

The aim of this study was to determine whether extended olfactory testing within a single olfactory task and/or across olfactory tasks increases diagnostic accuracy of olfactory testing in Parkinson's disease (PD). Olfactory function was assessed using an extended version of the "Sniffin' Sticks", comprising 32-item odor identification and discrimination tasks, and a detection threshold task in 52 PD patients and 50 controls, all aged between 49 and 78 years. ROC curves based on sensitivity and specificity estimates were used to compare the diagnostic accuracy of extended and combined olfactory testing. There was no significant difference in diagnostic accuracy between the 16-item and the 32-item versions of the odor identification or discrimination test. The single olfactory test that was best in discriminating between PD patients and controls was a 16-item odor identification test. A combination of the 16-item identification test and the detection threshold task had a significantly higher area under the curve than the 16-item odor identification test alone. In conclusion, extended testing across, and not within, olfactory tasks increases diagnostic accuracy of olfactory testing in PD. A combination of an odor detection threshold task and a 16-item odor identification test had the highest sensitivity and specificity in distinguishing between PD patients and controls.

Previous data on the prevalence of olfactory dysfunction in Parkinson's disease (PD) range from 45% to 90%. The present multicenter study aimed to provide data on the prevalence of smell loss in a large sample of PD patients from three independent populations. Olfactory sensitivity was tested in 400 patients from Australia, Germany, and The Netherlands by means of a psychophysical olfactory test, the "Sniffin' Sticks", which is comprised of 3 subtests of olfactory function. Out of the total number of patients 45.0% presented as functionally anosmic, 51.7% were hyposmic, whereas only 3.3% were normosmic. This indicates that 96.7% of PD patients present with significant olfactory loss when compared to young normosmic subjects. This figure falls to 74.5%, however, when adjusted to age-related norms. Thus, olfactory dysfunction should be considered as a reliable marker of the disease.

In view of the epidemic of obesity, one of the aims of the food industry is to develop good-tasting food products that may induce an increased level of satiation, preventing consumers from overeating. This review focuses on the possibility of using aroma as a trigger for inducing or increasing satiation. Using a novel approach of atmospheric pressure chemical ionization-mass spectrometry (APcl-MS) in combination with olfactometry, the relative importance of different aroma concepts for satiation was studied, from both consumer and food product points of view. The extent of retronasal aroma release appears to be a physiological feature that characterizes a person. Although the extent of retronasal aroma release appears to be subject specific, food product properties can be tailored in such a way that these can lead to a higher quality and/or quantity of retronasal aroma stimulation. This in turn provokes enhanced feelings of satiation and ultimately may contribute to a decrease in food intake.

Vermindering van het suikergehalte van voedingsmiddelen en dranken is met geuren te compenseren. TIFN, WUR en NIZO food research deden onderzoek naar appelsap. Optimalisatie van de combinatie van geurstoffen die van nature in het product voorkomen (clean label!) maakte een suikerreductie van 12% mogelijk zonder dat het sap minder zoet smaakte

Inadequate nutritional intake is the predominant cause of malnutrition in older persons. It is one of the most common and devastating conditions in nursing home residents. It is multifactorial and treatment or nutrition care plans should try to address the main causes. Such plans often include means to stimulate appetite to prevent or treat anorexia. One important stimulus, which can be modulated easily, is the meal ambiance. This article deals with the theory or mechanism behind this meal ambiance stimulus, discusses some study results, and makes practical recommendations.

Sensory satiation is probably one of the most important factors in meal termination. In this paper, the use of aromas to induce satiation via dairy products is illustrated by means of two examples: the use of organic acids, obtained by fermentation; and altering the extent of retro-nasal aroma release. In a double-blind placebo-controlled randomised cross-over preload-test meal design, it was demonstrated that a dairy beverage fermented with propionic acid bacteria was perceived as more satiating than a non-fermented equivalent dairy beverage. Satiety-inducing effects lasted up to 50 min. However, ad libitum energy intake was not reduced in the time frame tested. Another approach is to increase satiation by making use of differences in retro-nasal aroma release profiles. It is known that the physical structure of a food product is important for the extent of retro-nasal aroma release, i.e. solid foods generate a longer retro-nasal aroma release compared to liquid foods. This is possibly also related to satiation. Using olfactometry, aroma stimuli can be administered separately from other stimuli, such as different ingredients, textures and tastes. Hence, the relative importance of aroma stimuli apart from other stimuli on satiation mechanisms can be investigated. In a double-blind placebo-controlled randomised cross-over full factorial design, it was shown that perceived satiation can be increased by altering the extent of aroma release during consumption of a liquid dairy product

The invention provides a method for the production of a food product comprising a tastant. The food product according to the invention has a tastant bulk weight percentage and an inhomogeneous tastant bulk distribution. The invention provides the use of an inhomogeneous tastant bulk distribution in a food product for providing a food product with a reduced tastant bulk weight percentage. Further, the invention provides the use of an inhomogeneous tastant bulk distribution in a food product for enhancing and/or improving the sensory perception of the tastant in a food product.

OBJECTIVES: To determine whether time‐series analysis of magnetoencephalography (MEG) data is a suitable method to study brain activity related to olfactory information processing, and to detect differences in odor‐induced brain activity between patients with Parkinson's disease (PD) and controls. METHODS: Whole head 151‐channel MEG recordings were obtained in 21 controls and 20 patients with PD during a 10‐min olfactory stimulus paradigm, consisting of 10 alternating rest‐stimulus cycles (30 s each), using phenylethyl alcohol administered by means of a Burghart olfactometer. Relative spectral power and synchronization likelihood (SL; an unbiased measure of functional connectivity) were calculated for delta, theta, alpha1, alpha2, beta, and gamma frequency bands. RESULTS: In controls, olfactory stimulation produced an increase in theta power and a decrease in beta power. In patients with PD, there was a decrease in alpha1 power. No significant interaction between group and condition was found for spectral power. SL analysis revealed a significantly different response to olfactory stimulation in patients with PD compared to controls. In controls, the odor stimulus induced a decrease in local beta band SL. The response in patients with PD involved a decrease in intrahemispheric alpha2 band SL. CONCLUSION: This is the first study to show that time‐series analysis of MEG data, including spectral power and SL, can be used to detect odor‐induced changes in brain activity. In addition, differences in odor‐induced brain activity were found between patients with PD and controls using analysis of SL, but not of spectral power. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.

Sensory properties are greatly involved in the process of satiation. Regarding the nature of sensory signals, an important distinction can be made between sweet and savory taste. It is unclear, however, whether sweet and savory differ in their influence on satiation. Our objective was to investigate the difference between a sweet and savory taste on satiation, independent of palatability, texture, energy density, and macronutrient composition. A crossover design was used, consisting of 3 test conditions in which 2 tastes (sweet and savory) were compared. Sixty-four healthy, nonsmoking, unrestrained participants (18 males and 46 females), with a mean age of 22.3 ± 2.4 y and a mean BMI of 21.6 ± 1.7 kg/m2, enrolled. Rice was used as a test meal served in either a sweet or savory version. The meals were similar in palatability, texture, energy density, and macronutrient composition. Ad libitum intake, eating rate, and changes in pleasantness and appetite during the meals were measured. Ad libitum intake did not differ between the 2 meals; participants ate a mean of 314 ± 144 g of the sweet meal and 333 ± 159 g of the savory meal. Eating rate (sweet, 38 ± 14 g/min; savory, 37 ± 14 g/min) and changes in pleasantness and appetite during the meals were similar. Homogeneous meals with a sweet or savory taste, similar in palatability, texture, energy density, and macronutrient composition, do not differ in their influence on satiation in normal weight young adults

A higher viscosity of a food leads to a longer orosensory stimulation. This may facilitate the learned association between sensory signals and metabolic consequences. In the current study we investigated the effect of viscosity on learned satiation. In two intervention groups a low viscosity (LV) yogurt (n = 24) and a high viscosity (HV) yogurt (n = 22) was offered ad libitum for breakfast. In a learning period of 4 weeks, subjects consumed ad libitum a novel flavoured high energy density (HED) yogurt (150 kcal/100 g) or low energy density (LED) yogurt (50 kcal/100 g), with 10 exposures to each yogurt on alternate days. Over the repeated exposures, an interaction effect of exposure time * energy * viscosity on intake was seen (F(1,771) = 4.12; p = 0.04). In the HV intervention group a borderline significant interaction between exposure and energy density was observed (F(1,369) = 3.61; p = 0.06); after 10 exposures, the LED yogurt resulted in a 46 ± 16 g higher intake compared with the HED yogurt. In the LV group, no significant interaction between exposure and energy density was seen (F(1,401) = 1.04; p = 0.31); after 10 exposures intake difference between the LED and HED yogurts was only 1.5 ± 15 g. These results suggest that a higher viscosity facilitates learned satiation. © 2009 Elsevier Inc. All rights reserved.

The time difference between the electrocardiogram and impedance cardiogram can be considered as a measure for the time delay between the electrical and mechanical activities of the heart. This time interval, characterized by the pre-ejection period (PEP), is related to the sympathetic autonomous nervous control of cardiac activity. PEP, however, is difficult to measure in practice. Therefore, a novel parameter, the initial systolic time interval (ISTI), is introduced to provide a more practical measure. The use of ISTI instead of PEP was evaluated in three groups: young healthy subjects, patients with Parkinson's disease, and a group of elderly, healthy subjects of comparable age. PEP and ISTI were studied under two conditions: at rest and after an exercise stimulus. Under both conditions, PEP and ISTI behaved largely similarly in the three groups and were significantly correlated. It is concluded that ISTI can be used as a substitute for PEP and, therefore, to evaluate autonomic neuropathy both in clinical and extramural settings. Measurement of ISTI can also be used to non-invasively monitor the electromechanical cardiac time interval, and the associated autonomic activity, under physiological circumstances. © 2008 Institute of Physics and Engineering in Medicine.

OBJECTIVES: The aim of the study was to establish normative values for the two culture dependent components (odour identification and odour discrimination) of the "Sniffin' Sticks" test battery in the Dutch population over 45 years of age, and to assess the influence of age and sex on olfactory function in this population. METHODS: This study was performed in 150 healthy Dutch subjects (87 male and 63 female, mean age 59.2 years, range 45-78 years). Olfactory performance was assessed using the odour identification and discrimination parts of the "Sniffin' Sticks" test battery. RESULTS: In women, odour discrimination scores declined significantly with age, whereas there was no effect of age on odour discrimination performance in men. For odour identification, there were no effects of age or sex in this population. A moderate correlation was found between identification and discrimination test scores. CONCLUSION: Provisional population-specific normative data for olfactory testing using the identification and discrimination parts of the "Sniffin' Sticks" olfactory test battery have been established for the Dutch population over 45 years of age. The current data are applicable to the clinical evaluation of patients with olfactory disorders.