Digestibility, palatability and emotional status after ingestion of an iced dessert: analysis of subjective responses in 100 healthy volunteers

Food choices are influenced by many factors, perhaps the most important being availability. However, the desire to consume one item over another may be viewed as an outcome of sensory hedonic likes, situation and current internal state. In a previous preliminary report, an improvement of joy and mood, associated with good data of digestibility and palatability, was observed in a group of 30 healthy female subjects who consumed a coffee-flavoured iced dessert immediately after a standardized meal. The aim of this study is to confirm the results previously obtained in a smaller population and to investigate whether any differences between male and female subjects could be observed concerning the digestive process and emotional status. One hundred volunteers, after ENT and psychological assessment, were asked to fill out a Psycho-Emotional Questionnaire to assess their basal emotional pattern before the consumption of an iced coffee-flavoured dessert after a standard meal. After the meal they completed an Organoleptic-Sensory questionnaire, a Dynamic Digestibility questionnaire and again the Psycho-Emotional Questionnaire. In our study, most of the 100 subjects found the tested coffee-flavoured iced dessert pleasant according to the Organoleptic-Sensorial Questionnaire (OSQ), in terms of taste, aspect, texture and smell; moreover, the Dynamic Digestibility Questionnaire (DDQ) showed a good digestive experience in 71 subjects. According to the Psycho-Emotional Questionnaire (PEQ), an improvement of joy, activation and mood, associated with good data of digestibility and palatability was recorded. All these observations are statistically significant and the results seem to show a positive correlation between pleasure in eating such a product and emotional status. No statistically significant differences were recorded between male and female subjects.     

Palatability, digestibility and emotional pattern in 60 healthy volunteers after ingestion of an iced dessert presented in four different flavours: a subjective evaluation

Several variables lead to changes in human and animal eating behaviour and food choices. A pivotal role is played by food palatability, represented by food, smell, taste, texture, appearance and temperature. The aim of our study is to assess the potential differences in palatability and digestibility of four different flavoured iced desserts, consumed at the end of a standardized meal, and their impact on the emotional status of 60 healthy volunteers. Sixty healthy volunteers, after ENT and psychological assessment, were asked to fill out a Psycho-Emotional Questionnaire (PEQ) to assess their basal emotional pattern before the consumption of an iced dessert at the end of a standard meal, after which they completed an Organoleptic-Sensory Questionnaire (OSQ), a Dynamic Digestibility Questionnaire (DDQ) and again the PEQ. Four different flavors (lemon, tangerine, pineapple and chocolate) were tested on 4 consecutive days on the same subjects. Most of the 60 subjects, by means of OSQ, found taste, aspect, texture and smell of the 4 flavours pleasant, lemon and tangerine were the freshest and lightest. The DDQ identified pineapple and chocolate dessert as those less digestible. By means of PEQ we recorded an improvement in joy, mood and activation, associated with good data of digestibility and palatability after the consumption of all flavors. Our data showed that all flavors improve joy, mood and activation, after their consumption, without statistically significant differences. However, among the tested flavours, lemon and tangerine appear to be the most pleasant and those which facilitate the digestive process.     

The rules of formation of the olfactory representations found in the orbitofrontal cortex olfactory areas in primates.

Approximately 35% of neurons in the orbitofrontal cortex taste and olfactory areas with olfactory responses provide a representation of odour that depends on the taste with which the odour has been associated previously. This representation is produced by a slowly acting learning mechanism that learns associations between odour and taste. Other neurons in the orbitofrontal cortex respond to both the odour and to the mouth feel of fat. The representation of odour thus moves for at least some neurons in the orbitofrontal cortex beyond the domain of physico-chemical properties of the odours to a domain where the ingestion-related significance of the odour determines the representation provided. Olfactory neurons in the primate orbitofrontal cortex decrease their responses to a food eaten to satiety, but remain responsive to other foods, thus contributing to a mechanism for olfactory sensory-specific satiety. It has been shown in neuroimaging studies that the human orbitofrontal cortex provides a representation of the pleasantness of odour, in that the activation produced by the odour of a food eaten to satiety decreases relative to another food-related odour not eaten in the meal. In the same general area there is a representation of the pleasantness of the smell, taste and texture of a whole food, in that activation in this area decreases to a food eaten to satiety, but not to a food that has not been eaten in the meal.     

Orosensory considerations

The chemical senses (taste, smell, and chemical irritation) convey information from the external to the internal environment. This information influences an organism's quality of life, safety, reproductive function, and, to the present point, nutritional status. To illustrate this role, the effects of chemosensory stimulation on food choice, gastrointestinal function, and energy balance will be briefly reviewed. Each role is achieved, in part, by the chemosensory cue initiating anticipatory responses for an impending homeostatic challenge, a meal.     

Taste reactivity patterns in domestic cats (Felis silvestris catus)

The present study is aimed at finding taste reactivity patterns in domestic cats (Felis silvestris catus) which reflect 'liking' or perceived palatability. Three groups of nonstressed cats living in households were formed which a priori were expected to differ in motivational state for eating food items (more or less hungry), and which were offered two different food items differing in general taste properties (more or less flavourful food, MFF and LFF, respectively) around the time that they were fed their normal food. Analysis of the amount of food eaten showed that MFF was consumed regardless of hunger level and that LFF was consumed depending on the hunger level of cats: the more hungry cats ate more of LFF than the less hungry cats. Analysis of post-meal behavioural sequences showed that the 'MFF consumption sequence' differed from the 'LFF refusal sequence' and that the 'LFF consumption sequence' strongly resembled the 'MFF consumption sequence' but also contained elements of the 'LFF refusal sequence'. Subsequent analysis of the frequencies and total durations of behavioural patterns showed that two kinds of patterns existed, possibly reflecting two 'palatability dimensions': hedonic taste reactivity patterns (lick/sniff feeding bowl, lip lick and groom face) and aversive taste reactivity patterns (lick/sniff food and lick nose). These dimensions may be combined to obtain a single palatability score.     

Intraperitoneal injections of low doses of C75 elicit a behaviorally specific and vagal afferent-independent inhibition of eating in rats

Central and intraperitoneal C75, an inhibitor of fatty acid synthase and stimulator of carnitine palmitoyl-transferase-1, inhibits eating in mice and rats. Mechanisms involved in feeding inhibition after central C75 have been identified, but little is yet known about how systemic C75 might inhibit eating. One issue is whether intraperitoneal C75 reduces food intake in rats by influencing normal physiological controls of food intake or acts nonselectively, for example by eliciting illness or aversion. Another issue relates to whether intraperitoneal C75 acts centrally or, similar to some other peripheral metabolic controls of eating, activates abdominal vagal afferents to inhibit eating. To further address these questions, we investigated the effects of intraperitoneal C75 on spontaneous meal patterns and the formation of conditioned taste aversion (CTA). We also tested whether the eating inhibitory effect of intraperitoneal C75 is vagally mediated by testing rats after either total subdiaphragmatic vagotomy (TVX) or selective subdiaphragmatic vagal deafferentations (SDA). Intraperitoneal injection of 3.2 and 7.5 mg/kg of C75 significantly reduced food intake 3, 12, and 24 h after injection by reducing the number of meals without affecting meal size, whereas 15 mg/kg of C75 reduced both meal number and meal size. The two smaller doses of C75 failed to induce a CTA, but 15 mg/kg C75 did. The eating inhibitory effect of C75 was not diminished in either TVX or SDA rats. We conclude that intraperitoneal injections of low doses of C75 inhibit eating in a behaviorally specific manner and that this effect does not require abdominal vagal afferents.     

The bioelectronic nose and tongue using olfactory and taste receptors: Analytical tools for food quality and safety assessment

Food intake is the primary method for obtaining energy and component materials in the human being. Humans evaluate the quality of food by combining various facets of information, such as an item of food's appearance, smell, taste, and texture in the mouth. Recently, bioelectronic noses and tongues have been reported that use human olfactory and taste receptors as primary recognition elements, and nanoelectronics as secondary signal transducers. Bioelectronic sensors that mimic human olfaction and gustation have sensitively and selectively detected odor and taste molecules from various food samples, and have been applied to food quality assessment. The portable and multiplexed bioelectronic nose and tongue are expected to be used as next-generation analytical tools for rapid on-site monitoring of food quality. In this review, we summarize recent progress in the bioelectronic nose and tongue using olfactory and taste receptors, and discuss the potential applications and future perspectives in the food industry.     

Food intake is influenced by sensory sensitivity

Wide availability of highly palatable foods is often blamed for the rising incidence of obesity. As palatability is largely determined by the sensory properties of food, this study investigated how sensitivity to these properties affects how much we eat. Forty females were classified as either high or low in sensory sensitivity based on their scores on a self-report measure of sensory processing (the Adult Sensory Profile), and their intake of chocolate during the experiment was measured. Food intake was significantly higher for high-sensitivity compared to low-sensitivity individuals. Furthermore, individual scores of sensory sensitivity were positively correlated with self-reported emotional eating. These data could indicate that individuals who are more sensitive to the sensory properties of food have a heightened perception of palatability, which, in turn, leads to a greater food intake.     

Demand Characteristics of the Research Setting Can Influence Indexes of Negative Affect-Induced Eating in Obese Individuals

Measures of negative affect-induced eating (NAIE) are common in clinical research with obese individuals. However, previous studies suggest that measures of NAIE can be induced by social desirability tendencies or demand characteristics of the research setting. Using an experimental design, the present study tested the effects of demand characteristics of the research setting on selfreport and behavioral indexes of NAIE. Obese and nonobese subjects (n=107) were randomly assigned to an experimental or control group. Experimental subjects received a lecture indicating an association between emotional eating and obesity; control subjects received no information. Outcome measures were indexes of NAIE from a questionnaire, food diaries, and food intake during a laboratory “taste test.” We hypothesized that the association between relative body mass and NAIE would be stronger among subjects receiving the lecture manipulation than control subjects. Results indicated that NAIE indexes, particularly from food diaries, were influenced modestly by research demand characteristics. We conclude that demand characteristics of the research setting can affect indexes of NAIE among obese persons.     

Lack of evidence for a marked endogenous component determining food intake in humans during forced desynchrony

In an attempt to investigate the relative importance of endogenous and exogenous factors in determining food intake, 14 healthy subjects were studied while living in an Isolation Unit (where external time cues were absent) for eighteen 28 h "days" (equal to 21 solar days). The subjects were free to spend their waking time as they chose, and they had a free choice of what they ate and when they ate it. The only restrictions were that no naps were allowed in the "daytime," that some time was required to perform a variety of tests at regular intervals throughout the 18.67 h waking periods, and that any food preparation had to be performed by the subjects themselves. Core (rectal) temperature and activity were monitored throughout, and the subjects answered a questionnaire on their eating habits at 3 h intervals during the waking periods. The questionnaire investigated reasons for eating or not eating a meal during the previous 3 h and, if a meal had been eaten, its type, the factors influencing that choice, and the subjects' subjective responses (hunger before, enjoyment during, and satiety after) to it. The results were analyzed (two-way ANOVA) in terms of both the imposed day length (the exogenous component) and the free-running period of the temperature rhythm (the endogenous component). Results indicated that by far the main reason for eating/not eating was hunger/lack of hunger rather than factors such as food availability and time-pressure. There were statistically significant effects of time within the imposed waking periods upon the type of meal eaten--"breakfast" tending to be a snack, "lunch" a small hot meal, and the "evening meal" a large hot meal. Hot meals (whether small or large) were associated with more hunger before the meal, more enjoyment of the meal, and a greater degree of satiety afterward than were cold meals. These effects suggest that the individuals adjusted their eating habits to fit in with the imposed wake times. By contrast, the effect of circadian phase upon food intake, the type of meal eaten, and subjective responses to the meal was much weaker, and either statistically nonsignificant (P > 0.10) or only marginally so (0.10 > P > 0.05). For example, a large hot meal was chosen as readily for an "evening meal," and subjective responses to it were the same, at whatever circadian phase it was eaten. We conclude that food intake during forced desynchronization is dominated by the waking schedule rather than by circadian influences; some of the implications of these findings when eating habits and the metabolism of food are concerned, particularly in night workers, are considered briefly.     

Retrospective Reports of Child Feeding Practices,Current Eating Behaviors,and BMI in College Students

Research concerning child feeding practices has focused on children and adolescents, and little is known about how feeding practices used in childhood relate to eating behaviors and weight status in early adulthood. We assessed college students' and their parents' retrospective reports of child feeding practices used when the students were in middle childhood. We also assessed the college students' current reports of their eating behaviors using the Dutch Eating Behavior Questionnaire (DEBQ) and the Intuitive Eating Scale (IES), and measured their current BMI. Results showed that college students' and their parents' reports about previous parental use of child feeding practices were not correlated. Parent reports of their own use of child feeding practices were more related to students' eating behaviors and BMI than were students' recollections about feeding practices used by their parents. An analysis of gender effects showed that there were positive correlations between parental child feeding practices, BMI, and emotional eating for female students. These relationships did not exist for male students. The results suggest that child feeding practices recollected by parents are linked to the development of emotional eating and weight status of women in early adulthood.     

Functions of the orbitofrontal and pregenual cingulate cortex in taste, olfaction, appetite and emotion

Complementary neurophysiological recordings in macaques and functional neuroimaging in humans show that the primary taste cortex in the rostral insula and adjoining frontal operculum provides separate and combined representations of the taste, temperature, and texture (including viscosity and fat texture) of food in the mouth independently of hunger and thus of reward value and pleasantness. One synapse on, in the orbitofrontal cortex, these sensory inputs are for some neurons combined by learning with olfactory and visual inputs. Different neurons respond to different combinations, providing a rich representation of the sensory properties of food. The representation of taste and other food-related stimuli in the orbitofrontal cortex of macaques is found from its lateral border throughout area 13 to within 7 mm of the midline, and in humans the representation of food-related and other pleasant stimuli is found particularly in the medial orbitofrontal cortex. In the orbitofrontal cortex, feeding to satiety with one food decreases the responses of these neurons to that food, but not to other foods, showing that sensory-specific satiety is computed in the primate (including human) orbitofrontal cortex. Consistently, activation of parts of the human orbitofrontal cortex correlates with subjective ratings of the pleasantness of the taste and smell of food. Cognitive factors, such as a word label presented with an odour, influence the pleasantness of the odour, and the activation produced by the odour in the orbitofrontal cortex. Food intake is thus controlled by building a multimodal representation of the sensory properties of food in the orbitofrontal cortex, and gating this representation by satiety signals to produce a representation of the pleasantness or reward value of food which drives food intake. A neuronal representation of taste is also found in the pregenual cingulate cortex, which receives inputs from the orbitofrontal cortex, and in humans many pleasant stimuli activate the pregenual cingulate cortex, pointing towards this as an important area in motivation and emotion.     

Aging Effects on Anatomy and Neurophysiology of Taste and Smell1

Taste and smell have a primary role in food ingestion. Therefore, to understand why eating habits alter in elderly people, age-related differences in the chemical senses should be investigated. In early anatomical studies, substantial decreases in numbers of taste buds in old human and mouse circumvallate papillae were observed. However, recent investigations in humans, monkeys, and rats indicate that there is not a significant loss of taste buds in old age. Neurophysiological recordings from the chorda tympani nerve, innervating taste buds in fungiform papillae, demonstrate significant but small differences in response magnitudes for some chemicals in old rats. Greater age-related differences have been observed in the olfactory sense. Numbers of receptor neurons in the rat olfactory epithelium initially increase in adults and then decline in old animals; this decline is reflected in subsequent changes in the olfactory bulb. However, numbers of synapses in the bulb per receptor neuron are increased in the oldest rats, suggesting some compensatory mechanism. Differences in degree of aging effects in taste and smell might relate to the nature of receptors: a modified epithelial cell in taste versus a neuron in smell. However, in both sensory systems, large numbers of receptors remain even in old age. Since taste bud cells and olfactory receptors turn over and are replaced throughout life, the peripheral taste and smell systems might be relatively resistant to aging effects.     

How about Lunch? Consequences of the Meal Context on Cognition and Emotion

Although research addresses the effects of a meal’s context on food preference, the psychological consequences of meal situations are largely unexplored. We compared the cognitive and emotional effects of a restaurant meal eaten in the company of others to a solitary meal consumed in a plain office using pre- and post-tests analysis and controlling for the kind and amount of food consumed. Three tasks were conducted, measuring: (1) semantic memory (2) cognitive control and error monitoring, and (3) processing of emotional facial expressions. Covert processes in these tasks were assessed with event-related brain potentials. A mood rating questionnaire indicated a relaxation effect of the restaurant as compared to the plain meal situation. The restaurant meal increased sensitivity to threatening facial expressions and diminished cognitive control and error monitoring. No effects were observed for semantic memory. These findings provide the first experimental evidence that a restaurant meal with a social component may be more relaxing than a meal eaten alone in a plain setting and may reduce cognitive control.     

Diet palatability and growth efficiency: Evidence for a physiological interrelationship in rats

The total food intake and growth efficiency of growing rats were not affected by the feeding of a mild protein restricted (10%) diet containing an aversive taste stimulus. However, growing rats fed the same diet for a period of 18 days, suffered an inhibition of growth efficiency if the taste character of the diet was changed daily by the addition of a single but different aversive stimulus. For a period of time (9 days), these changes in diet palatability did not affect the total food intake. Rats fed diets containing a combination of the aversive taste changes and commercial soybean trypsin inhibitors, suffered an additional inhibition of growth efficiency. It is postulated that these manipulations in diet palatability interfered with digestive or metabolic processes.     

CLASSIFICATION OF CHEESES ACCORDING TO THEIR CLOSENESS TO THE CHEDDAR CHEESE CONCEPT1

An important issue in consumer oriented studies is to measure how closely a specific product or perception matches the representation people have of it. We used a concept matching technique to assess the degree to which a variety of different cheeses matched subjects’ concepts of Cheddar cheese. Eighteen subjects made their judgments using their own past experiences with Cheddar cheeses. They made judgments in three separate conditions: only the odor, only the taste and texture and normal eating. This technique provided valid and reliable information on the extent to which the cheeses matched the subjects’ concept of Cheddar cheese. Agreement between classifications of cheeses based on taste and texture only and based on normal eating was high (R=0.90). Agreement between classifications based only on odor and those based on normal eating was weaker (R-0.59). Thus, the taste and texture of the cheeses were more useful than the odor for classifying cheeses as Cheddar.     

Food reward in the absence of taste receptor signaling

Food palatability and hedonic value play central roles in nutrient intake. However, postingestive effects can influence food preferences independently of palatability, although the neurobiological bases of such mechanisms remain poorly understood. Of central interest is whether the same brain reward circuitry that is responsive to palatable rewards also encodes metabolic value independently of taste signaling. Here we show that trpm5-/- mice, which lack the cellular machinery required for sweet taste transduction, can develop a robust preference for sucrose solutions based solely on caloric content. Sucrose intake induced dopamine release in the ventral striatum of these sweet-blind mice, a pattern usually associated with receipt of palatable rewards. Furthermore, single neurons in this same ventral striatal region showed increased sensitivity to caloric intake even in the absence of gustatory inputs. Our findings suggest that calorie-rich nutrients can directly influence brain reward circuits that control food intake independently of palatability or functional taste transduction.