Article

The biological basis of food perception and acceptance

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Abstract

We have discarded the old tongue map (sweet on the tip, etc.) for study of the interactions among taste nerves. Taste is mediated by the chorda tympani (anterior) and the glossopharyngeal (posterior) nerves. Unilateral anesthesia of the chorda tympani intensified some taste sensations from the area innervated by the contralateral glossopharyngeal. For some subjects, even with no stimulation, a phantom taste sensation appeared in the area innervated by the contralateral glossopharyngeal nerve. Thus when one taste nerve is damaged another compensates; however, the cost may be a taste phantom.Work on genetic variation in taste has identified supertasters of PROP (6-n-propylthiouracil) who are unusually sensitive to bitters and sweets as well as the burn from chili pepper (active ingredient capsaicin). Supertasters appear to have more tastebuds and since tastebuds have trigeminal neurons (mediating pain) associated with them, there is an association between perception of taste and irritation.

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... During the middle decades of the 20th Century, it was widely believed that the gustatory receptors responsible for coding different basic taste properties (such as sweet, sour, bitter, and salty) were asymmetrically distributed over the surface of the tongue. According to the now discredited tongue map (see Amerine et al., 1965;Bartoshuk, 1993;Feeney and Hayes, 2014), sweet receptors were thought to be located on the front of the tongue, bitter receptors on the back, and receptors capable of detecting salt and sour tastes on the sides. The emergence of the tongue map was linked by Linda Bartoshuk (1978) to the publication of Edwin G. Boring's 1942 textbook Sensation and perception in the history of experimental psychology, in which the famous North American psychologist redescribed David Pauli Hanig's (1901) thesis data published in an earlier German text entitled 'The psychophysics of taste'. ...
... The notion of the tongue map has been dismissed by the majority of contemporary writers (e.g., Bartoshuk, 1993;O'Connor, 2008). However, it is perhaps worth revisiting the idea, given a closer inspection of the literature soon highlights how its putative existence has been grounded on a number of rather different assumptions. ...
... What is more, the taste buds/papillae are not distributed evenly over the surface of the tongue (see Fig. 3). The taste buds in the soft palate, pharynx, and epiglottis are not grouped in papillae (Bartoshuk, 1993). ...
Article
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There is undoubtedly a spatial component to our experience of gustatory stimulus qualities such as sweet, bitter, salty, sour, and umami, however its importance is currently unknown. Taste thresholds have been shown to differ at different locations within the oral cavity where gustatory receptors are found. However, the relationship between the stimulation of particular taste receptors and the subjective spatially-localized experience of taste qualities is uncertain. Although the existence of the so-called ‘tongue map’ has long been discredited, the psychophysical evidence clearly demonstrates significant (albeit small) differences in taste sensitivity across the tongue, soft palate, and pharynx (all sites where taste buds have been documented). Biases in the perceived localization of gustatory stimuli have also been reported, often resulting from tactile capture (i.e., a form of crossmodal, or multisensory, interaction). At the same time, varying responses to supratheshold tastants along the tongue’s anterior-posterior axis have putatively been linked to the ingestion-ejection response. This narrative review highlights what is currently known concerning the spatial aspects of gustatory perception, considers how such findings might be explained, given the suggested balanced distribution of taste receptors for each basic taste quality where taste papillae are present, and suggests why knowing about such differences may be important.
... A Finnish study of 331 pairs of adult twins, for instance, revealed that 18-58% of the preference for spicy food could be explained by shared genetic influence (Törnwall et al., 2012). Some researchers have argued that the preference for spicy food is influenced by both taste phenotype and oral anatomy (e.g., Bartoshuk, 1993). Relevant here, supertasters (e.g., those with a propensity toward having a higher density of taste buds; Miller & Reedy, 1990; though see Garneau et al., 2014) are thought to experience a more intense burn in response to the ingestion of capsaicin, at least on the tip of the tongue (e.g., Bartoshuk, 1993;Karrer et al., 1992). ...
... Some researchers have argued that the preference for spicy food is influenced by both taste phenotype and oral anatomy (e.g., Bartoshuk, 1993). Relevant here, supertasters (e.g., those with a propensity toward having a higher density of taste buds; Miller & Reedy, 1990; though see Garneau et al., 2014) are thought to experience a more intense burn in response to the ingestion of capsaicin, at least on the tip of the tongue (e.g., Bartoshuk, 1993;Karrer et al., 1992). That said, Törnwall et al.'s research failed to demonstrate any link between taster status and a preference for chilli in their Finnish twin sample. ...
Article
The last 500 years or so has seen a phenomenal increase of interest in piquant/spicy food around the world. In this review, the latest research documenting the crossmodal influences on the perception of oral piquancy/spiciness that have been established to date are summarized: Everything from the color of the foodstuff through the color of the plateware on which that food is served has been found to influence both the expected and experienced piquancy/spiciness of food. Furthermore, certain musical parameters have also been shown to enhance the perceived piquancy of the food in a restaurant setting. By contrast, spicy smells have not, as yet, attracted anything like as much research interest from the scientific community. Intriguingly, many of the crossmodal influences on piquancy/spiciness that have been documented to date appear to be more pronounced when the actual experience on tasting the food is close to the preconsumption expectations. And while many of the crossmodal effects in this area appear to mirror those found previously for basic taste and flavor stimuli, there is a sense in which the broader range of intensities of sensation experienced in relation to chili/capsaicin may mean that crossmodal influences are somewhat different in this case. Practical applications Piquancy/spiciness is a highly desirable food attribute. In fact, chiles are eaten by one in four of us every day. As yet, however, it has not attracted anything like the research interest that the basic tastes have. This review draws attention to the multisensory factors (including color, sound, etc.) that have recently been shown to modulate the experienced piquancy/spiciness of a dish. Given its widespread appeal, gaining a better understanding of this most desirable of oral sensations is likely to benefit food providers.
... Roughly 25% of the population are classed as supertasters, 50% as medium-tasters, and the remaining 25% as non-tasters. Supertasters are significantly less likely to find the bitter taste of alcohol (e.g., in beer), or the bitter-taste of caffeinated hot beverages, such as coffee, appealing (e.g., Bartoshuk, 1980Bartoshuk, , 2000. While the different worlds of taste in which we all live is most apparent for bitter-tasting food and drink items, an individual's taster status also affects their rating of the intensity of the other basic tastes as well (see Blakeslee & Salmon, 1935). ...
... Recently, Spinelli et al. (2018) also documented significant sex differences in the frequency of chile consumption in a sample of 1146 individuals as a part of the Italian Taste project. Taster status has also been reported to influence the perception, and hence presumably also the consumption, of chile (Bartoshuk, 1993;Karrer, Bartoshuk, Conner, Fehrenbaker, Grubin, & Snow, 1992; though see Törnwall et al., 2012, for a null result). 6 Nevertheless, any sex differences with regard to trigeminal stimulation would seem to have more of a psychological, rather than genetic, origin bearing in mind that the sex difference in the case of chile consumption, is seemingly restricted to just those cultures where conspicuous consumption acts as some kind of proxy for masculinity. ...
Preprint
In recent years, food and drink marketers have become increasingly interested in the question of whether there are any meaningful sex/gender differences in the world of taste/flavour perception. However, it turns out that while there are a large number of individual differences in the experience of food/drink, few, if any, fall neatly along sex/gender lines. As such, the marketers of food and drink need to tread very carefully when it comes to marketing food or beverage products specifically at men, or more usually, women. All too often, the brands entering this space soon find their attempts branded crass and/or sexist. Adopting a stealthy or implicit gender-based product development strategy is therefore perhaps more likely to succeed than the explicit targeting of food/beverage-related products in what is undoubtedly a highly-politicized area. That said, the one area where the public appear willing to accept products that are explicitly targeted at men or women is in the case of nutritional foods/supplements.
... Within this nutritional context, the genetic ability to taste the bitter compound 6-npropylthiouracil (PROP) has gained a consistent and appreciable consideration as a marker of general taste perception, dietary preferences, and habits that can impact on nutrition and health of individuals [30]. This important role assigned to PROP tasting is based on findings reporting that subjects who perceive PROP as intensively bitter (PROP super-tasters), have a higher sensitivity and lower preference, than non-tasters, to various oral stimuli, including other bitter substances [31][32][33][34][35][36], sweet stimuli [37], sour compounds [38], umami taste [39], irritants [40,41], high-fat/high-energy foods [42][43][44], astringent substances [45], and fruits and vegetables [46][47][48]. Some authors suggested that PROP-related sensory variations may be associated with olfactory function [49,50], and that PROP tasting may affect the perception of foods via aromas or flavors [51,52]. ...
... These results strongly support previous psychophysical data showing a direct relationship between perception of a wide range of oral stimuli and PROP taster status [31][32][33][34][35][36][37][38][42][43][44][45][46][47][48], that can be linked to changes in density of papillae across the PROP taster groups [37,[92][93][94][95][96]. This suggests that the phenotypic expression of the trait, which is strongly associated with density of papillae, is a critical determinant of the electrophysiological responses to the six taste qualities. ...
Article
Full-text available
Taste buds containing receptor cells that primarily detect one taste quality provide the basis for discrimination across taste qualities. The molecular receptor multiplicity and the interactions occurring between bud cells encode information about the chemical identity, nutritional value, and potential toxicity of stimuli before transmitting signals to the hindbrain. PROP (6-n-propylthiouracil) tasting is widely considered a marker for individual variations of taste perception, dietary preferences, and health. However, controversial data have been reported. We present measures of the peripheral gustatory system activation in response to taste qualities by electrophysiological recordings from the tongue of 39 subjects classified for PROP taster status. The waveform of the potential variation evoked depended on the taste quality of the stimulus. Direct relationships between PROP sensitivity and electrophysiological responses to taste qualities were found. The largest and fastest responses were recorded in PROP super-tasters, who had the highest papilla density, whilst smaller and slower responses were found in medium tasters and non-tasters with lower papilla densities. The intensities perceived by subjects of the three taster groups correspond to their electrophysiological responses for all stimuli except NaCl. Our results show that each taste quality can generate its own electrophysiological fingerprint on the tongue and provide direct evidence of the relationship between general taste perception and PROP phenotype.
... A Finnish study of 331 pairs of adult twins, for instance, revealed that 18-58% of the preference for spicy food could be explained by shared genetic influence (Törnwall et al., 2012). Some researchers have argued that the preference for spicy food is influenced by both taste phenotype and oral anatomy (e.g., Bartoshuk, 1993). Relevant here, supertasters (e.g., those with a propensity toward having a higher density of taste buds; Miller & Reedy, 1990; though see Garneau et al., 2014) are thought to experience a more intense burn in response to the ingestion of capsaicin, at least on the tip of the tongue (e.g., Bartoshuk, 1993;Karrer et al., 1992). ...
... Some researchers have argued that the preference for spicy food is influenced by both taste phenotype and oral anatomy (e.g., Bartoshuk, 1993). Relevant here, supertasters (e.g., those with a propensity toward having a higher density of taste buds; Miller & Reedy, 1990; though see Garneau et al., 2014) are thought to experience a more intense burn in response to the ingestion of capsaicin, at least on the tip of the tongue (e.g., Bartoshuk, 1993;Karrer et al., 1992). That said, Törnwall et al.'s research failed to demonstrate any link between taster status and a preference for chilli in their Finnish twin sample. ...
Article
The desire for piquant/spicy food has grown phenomenally over the last 500 years or so. In this review, I summarize the literature on this most intriguing of oral sensations, and summarize various explanations for why it may have become so liked by so many peoples around the world in recent years. A number of alternative hypotheses for the rise in popularity of this plant/fruit have been put forward and are briefly discussed. These include the masochistic/thrill-seeking hypothesis, the antimicrobial hypothesis, the thermoregulation/salivation-induction hypotheses, and medicinal/health/diet-based accounts.
... Roughly 25% of the population are classed as supertasters, 50% as medium-tasters, and the remaining 25% as non-tasters. Supertasters are significantly less likely to find the bitter taste of alcohol (e.g., in beer), or the bitter-taste of caffeinated hot beverages, such as coffee, appealing (e.g., Bartoshuk, 1980Bartoshuk, , 2000. While the different worlds of taste in which we all live is most apparent for bitter-tasting food and drink items, an individual's taster status also affects their rating of the intensity of the other basic tastes as well (see Blakeslee & Salmon, 1935). ...
... Recently, Spinelli et al. (2018) also documented significant sex differences in the frequency of chile consumption in a sample of 1146 individuals as a part of the Italian Taste project. Taster status has also been reported to influence the perception, and hence presumably also the consumption, of chile (Bartoshuk, 1993;Karrer, Bartoshuk, Conner, Fehrenbaker, Grubin, & Snow, 1992; though see Törnwall et al., 2012, for a null result). 6 Nevertheless, any sex differences with regard to trigeminal stimulation would seem to have more of a psychological, rather than genetic, origin bearing in mind that the sex difference in the case of chile consumption, is seemingly restricted to just those cultures where conspicuous consumption acts as some kind of proxy for masculinity. ...
Article
In this review, I highlight what is currently known about the sensory, psychological, and physical/nutritional, differences between men and women in terms of their sensory-discriminative and hedonic responses to multisensory tasting experiences. However, despite the evidence for there being numerous individual differences in tasting, few neatly support the claim that men and women live in different worlds of taste. Perhaps the only situation in which consumed products directed specifically at men and women would appear to succeed is when they are advertised as providing some sort of nutritional benefit to the end user.
... Aunque existen experimentos que han logrado inducir la preferencia por este sabor en ratas o chimpancés, los seres humanos son los únicos animales que consumen deliberadamente picante. A numerosas personas de todo el mundo les gusta consumir alimentos que contienen capsaicina, a pesar de su capacidad para provocar molestias, irritación, e incluso dolor (2). ...
... Results have been conflicting, likely due to variability in protocol and difficulty in rating individual taste perception. It was originally observed that intensity perception of 6-n-propylthiouracil (PROP), which is perceived as bitter at considerably lower concentrations depending on polymorphisms in the bitter receptor gene TAS2R38 11 , correlated with FPD 12,13 . Higher FPD has also been related to increased perception of sucrose, sodium chloride and citric acid in multiple studies 2,14-17 . ...
Article
Full-text available
Fungiform papillae house taste buds on the anterior dorsal tongue. Literature is inconclusive as to whether taste perception correlates with fungiform papillae density (FPD). Gustatory reflexes modulate the amount and composition of saliva subsequently produced, and thus may be a more physiologically objective measure of tastant-receptor interactions. Taste perception fluctuates with time but the stability of individual fungiform papillae is unclear. This study followed ten healthy volunteers longitudinally at baseline, one and six months. FPD, diameter and position were measured and participants rated intensity perception of sucrose, caffeine, menthol and capsaicin solutions. Salivary flow rate, protein concentration and relative changes in protein composition were measured following each tastant. FPD, diameter and position were unchanged at six months. FPD did not correlate with intensity rating for any taste. FPD did correlate with changes in salivary protein output following sucrose (ρ = 0.72, p = 0.02) and changes in levels of proline-rich protein and mucin 7 following capsaicin (ρ = 0.71, p = 0.02, ρ = 0.68, p = 0.04, respectively). These results suggest that over six months fungiform papillae are anatomically stable, playing a greater role in mediating the physiological salivary response to stimuli rather than determining the perceived intensity of taste.
... Taste perception varies greatly among individuals, strongly influencing food preferences and selection, and therefore nutritional status and health [5]. In particular, during the last decades, research has been focusing on bitter taste perception, and the genetic predisposition to perceive the bitter taste of 6-n-propylthiouracil (PROP) has gained considerable attention as a prototypical taste stimulus and an oral marker of food preferences and eating behavior [6]. Some additional markers include the density of fungiform papillae on the tongue tip [7] and thermal tasting [8]. ...
Article
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The role of taste perception, its relationship with oral microbiota composition, and their putative link with eating habits and food intake were the focus of the present study. A sample of 59 reportedly healthy adults (27 male, 32 female; age: 23.3 ± 2.6 years) were recruited for the study and taste thresholds for basic tastes, food intake, and oral microbiota composition were evaluated. Differences in taste perception were associated with different habitual food consumption (i.e., frequency) and actual intake. Subjects who were orally hyposensitive to salty taste reported consuming more bakery and salty baked products, saturated-fat-rich products, and soft drinks than hypersensitive subjects. Subjects hyposensitive to sweet taste reported consuming more frequently sweets and desserts than the hypersensitive group. Moreover, subjects hypersensitive to bitter taste showed higher total energy and carbohydrate intakes compared to those who perceived the solution as less bitter. Some bacterial taxa on tongue dorsum were associated with gustatory functions and with vegetable-rich (e.g., Prevotella) or protein/fat-rich diets (e.g., Clostridia). Future studies will be pivotal to confirm the hypothesis and the potential exploitation of oral microbiome as biomarker of long-term consumption of healthy or unhealthy diets.
... There are also important cross-cultural and individual differences in terms of people's coffee preferences (e.g., Van Doorn et al., 2017) and reasons for consuming coffee in the first place (see Labbe, Ferrage, Rytz, Pace, & Martin, 2015). Such differences may, in some small part, originate from differences in an individual's taster status (e.g., Bartoshuk, 1993;Garneau et al., 2014), or even gender (Cristovam, Russell, Patterson, & Reid, 2000). However, while it might be interesting to consider developing cups specifically for tasters and non-tasters (either different drinking receptacles for each group, or else perhaps different experiences, or textures, on different parts of cup), manufacturers would be well advised to stay away from the design of explicitly gendered coffee cups (see Paskin, 2018, for a recent unsuccessful foray in this area; and see Spence, 2019a, for a review). ...
Article
This review summarizes the latest evidence concerning the impact of the colour, shape, texture, weight, and other material properties of the drinking receptacle on the perception of coffee. The colour of the cup, for instance, has been shown to prime notions of sweetness (e.g., pink cup) or acidity (e.g., yellow or green cup) that may carry over to influence the tasting experience. Meanwhile, the shape and surface feel of the drinking vessel have also been shown to exert a profound influence over the perceived aroma/taste of coffee. Given that the various sensory attributes of the drinking vessel can exert such a striking influence over the drinking experience, the challenge, moving forward, is to optimize the design of the receptacle in order to enhance the multisensory tasting experience for the consumer. Given that different styles/varieties of specialty coffee have different dominant/desirable qualities (e.g., acidity/sweetness), in the future, the design of coffee cups may need to be customized for different coffee drinking experiences (e.g., origin or roast), much as seen in the world of fine wine (with different glasses for different grape varieties).
... Néanmoins, il existe des différences interindividuelles dans la sensibilité à l'amertume, déterminées génétiquement à l'aide du test 6-n-propylthiouracile (PROP/PTC) (Bartoshuk, 1994;Bartoshuk, 2006;Drewnowski, 2001a;Drewnowski, 2007;Tepper, 2008). Le PTC ou PROP est une molécule qui a un goût amer pour certaines personnes dites « sensibles » et n'a aucun goût pour d'autres dites « peu sensibles » (Bartoshuk, 1993). Ce test permet également d'identifier les sujets « super sensibles » qui seraient aussi plus sensibles aux autres stimuli, tels que le sucré (Bartoshuk, 1994;Tepper, 2008). ...
Thesis
Full-text available
Les graisses, les sucres et le sodium, nutriments impliqués dans l’apparition de maladies chroniques, participent aux propriétés sensorielles de nombreux aliments en termes de goût, texture et palatabilité et contribuent au plaisir associé à leur consommation. Par ailleurs, l’offre alimentaire a évolué ces dernières décennies, proposant des aliments plus riches en matières grasses, sucres et sodium présentant une forte attractivité sensorielle. Dans ce contexte, l’un des domaines de recherche encore peu exploré est la compréhension de l’influence des déterminants sensoriels sur les comportements alimentaires et l’apparition de l’obésité.L’objectif principal de ce travail de thèse était d’étudier l’association de l’attirance sensorielle pour le gras, le salé et le sucré et les caractéristiques individuelles, et d’évaluer son influence sur les consommations alimentaires et le statut pondéral, au sein d’une large population d’adultes français issus de la cohorte NutriNet-Santé.Des profils individuels selon les caractéristiques démographiques, socioéconomiques, psychologiques, de mode de vie et de santé ont été mis en évidence selon les niveaux d’attirance pour le gras-salé, le gras-sucré, le salé et le sucré.L’attirance pour le gras est associée à un risque augmenté d’apparition de l’obésité sur cinq ans de suivi, et une alimentation plus fréquemment défavorable à la santé contribue à expliquer cette relation. En revanche, l’attirance pour le sucré est inversement associée avec le risque d’obésité et cette relation est attribuable au sous-facteur de l’attirance les sucres naturels, associé à une alimentation de meilleure qualité nutritionnelle. Enfin, l’attirance pour le salé n’était pas associée avec la survenue de l’obésité.La modélisation par équations structurelles a mis en évidence que la restriction alimentaire est le prédicteur majeur de la prise de poids, et l’attirance sensorielle pour le gras est le déterminant le plus important des consommations alimentaires, devant l’effet d’autres déterminants pourtant reconnus dans la littérature. De nombreuses relations ont également été confirmées, telles que l’influence de l’âge, du sexe et du statut socioéconomique sur l’alimentation, ainsi que l’impact de l’alimentation et de l’activité physique sur une moindre prise de poids chez les sujets normo-pondéraux.Ces résultats illustrent l’important effet de l’attirance sensorielle, notamment pour le gras, sur les consommations alimentaires et le statut pondéral. Ils soulignent également la nécessité de considérer au premier plan la perception hédonique individuelle dans l’étude des comportements alimentaires.
... Sensory acceptability (taste, color, odor, texture and overall acceptability) attributes were evaluated on a nine-point hedonic scale of Bartoshuk [19]. ...
Article
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Banana fruit (Musa sp.) is consumed as a major source of carbohydrate for millions of people mostly in the tropics and subtropics. Worldwide, banana is the most wasted fruit; postharvest of the banana fruit records up to 40-60% loss, and this loss may be prevented by converting the green bananas to flour. This study was geared towards the need for an alternative means of flour production in the making of pastries as there exists an over-dependence of pastries made from cassava and cereals flour. Banana cultivars were processed into flour and made into pastries with sensory evaluation carried out afterwards. The sensory evaluation suggests that the pastries made; had moderately good hardness, good crispiness, good flavors, good taste, good texture, good hardness, good crispiness and good color to complement, Other sensory tests show that the pastries had good surface with a very good smell. This study shows that banana flour has the potentials to competing with flours made from common sources for the production pastries and related products.
... Earlier researchers considered that certain areas on the tongue are more sensitive than others to specific tastes (21,23), although concerns have been expressed about this notion in view of the lack of scientific basis. Further studies have clarified that taste is mediated by specialized epithelial cells distributed throughout the oral cavity, palate, lips, cheeks, pharynx, epiglottis, larynx, and the upper part of the esophagus (18,24). ...
Article
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Introduction The majority of patients receiving concurrent chemoradiotherapy frequently complain of changes in their taste perception, and other distressing symptoms affecting their quality of life. This study was undertaken to determine the pattern of gustatory impairment and its recovery in irradiated head and neck cancer patients in India. Materials and Methods Thirty patients undergoing radical head and neck irradiation were enrolled and assessed for the four basic taste quality (sweet, salt, sour and bitter) by a forced three-choice stimulus drop technique measuring their taste recognition thresholds at baseline, weekly during radiation therapy (RT) and every month for 6 months following completion of RT. Results The maximum taste loss for any taste quality developed after the third week of RT. Irrespective of the taste quality, the majority of patients developed their maximum taste loss in the fourth to sixth week. The maximum taste loss was highest (100%) for the bitter taste and least (40.7%) for the sweet taste. Taste recovery for sweet, salt and sour taste qualities started from the first month onwards, but not for bitter taste. All taste qualities were severely affected in patients with primary involvement of the oral cavity and oropharynx as compared with nasopharynx, hypopharynx and laryngeal tumors. Conclusions Taste dysfunction is a frequently ignored adverse effect of head and neck cancer treatment, seriously affecting the patient’s quality of life. Clinicians must make patients aware of this specific gustatory dysfunction and its pattern of recovery. Future efforts should be directed towards minimizing this dysfunction, specifically in tumors arising from the oral cavity and oropharynx.
... Some of the variation in response to these bitter compounds and others is linked to genetic differences in bitter taste receptor genes (TAS2Rs) [54][55][56][57][58][59][60]. Individual differences in perception are associated with differences in the liking and intake of foods [60][61][62][63][64]. This points to the importance of individual differences in perception that may result from genetic differences [59,65] (see Hayes et al. [66]) or dietary exposure [67][68][69][70], and is why longitudinal studies are preferred, where the patients act as their own control. ...
Article
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Individuals undergoing treatment for cancer can experience changes in taste or smell that are often assumed to affect constructs related to food behavior, although this relationship is rarely measured directly. To ascertain the extent to which measured changes in taste and smell during and after cancer treatment affect food behavior, we conducted a scoping review and completed a comparative analysis for studies that met our criteria, which were: they directly measured cancer patients’ (a) psychophysical response to taste and/or olfactory stimuli, and (b) food behavior (including food enjoyment, food preference, dietary intake) in people affected by cancer. Eleven studies met these criteria and were included in the review. All 11 studies evaluated taste and five also measured smell. A comparative analysis exploring taste and food behavior shows that a reduced sweet taste function (decreased sensitivity) was associated with a reduced intake of a variety of different macro and micro nutrients, reduced appetite, and overall lower energy intake. One out of six studies that measured smell and food measured observed changes in olfactory function following cancer treatment. There were no significant relationships reported between olfactory measures and food behavior. Taste changes that arise from cancer treatment appear to have a direct effect on food behavior, although there is a need for more research using standardized measures and larger sample sizes. A better understanding of taste alterations and their implications for dietary intake and food enjoyment will support optimal nutritional health by identifying strategies to help patients eat well during and after cancer treatment.
... Super-Tasters (STs), Medium-Tasters (MTs), Non-Taster (NTs)). Taster status grouping was based on 25%, 50%, 25% percentile distribution 30,36 : NTs (n=10) gLMS <10; MTs (n=18) gLMS 10 -59; and STs (n=10) gLMS ≥60. After the tasting session, participants practiced each of the discrete cognitive tasks in order to reduce the potential for learning effects in the experimental trials. ...
Article
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Encapsulated (Pod) coffee is increasingly popular and available in a range of flavor and intensity profiles. This study examined consumption of different coffee Pods on mood and cognitive performance. Thirty-eight participants (n=6 males, 32 females; age: 23.9±5.4 years; weight: 64.3±11.9 kg; BMI: 22.4±2.7 kg·m⁻²; mean±SD) completed 3 trials, consuming either Cosi, Dharkan, or Kazaar Pods following overnight caffeine abstention. Mood and cognitive performance (choice reaction-time (CRT), visual scanning (VS), Stroop) were measured before and 30 min post coffee consumption. Sensory characteristics were measured during coffee consumption. Accuracy, Reaction Time (RT) central tendency and whole RT distributions were analyzed. Bitterness, flavour-intensity, aroma and perceived caffeine content ratings increased for Cosi, Dharkan and Kazaar Pods respectively. Reduced ratings of sleepiness and headache; and increased ratings of concentration, alertness, excitement and happiness were observed with all Pods. Coffee improved CRT latency (before: 469±55 vs. after: 459±50 ms; p=0.031), but not visual scanning performance. Stroop RTs were faster after coffee (before: 854±193 vs. after: 766±156 ms; p<0.001); with control, congruent and incongruent trials facilitated by different aspects of the RT distribution. Consumption of Nespresso® Pod coffee improves mood and cognitive performance irrespective of caffeine content, habitual caffeine use and Pod sensory characteristics. However, the effects on cognitive function appear to be task dependent.
... Ancak bazı araştırmacılar tarafından yerel yiyecek tüketme davranışları üzerinde birey boyutunun daha çeşitli katkıları olduğu düşünülmektedir. (Bartoshuk, 1993;Kissileff vd., 1996). Dolayısıyla bu katkıları açıklamak için birçok çalışmada tüketicilerin/turistlerin yerel yiyecek tüketme davranışları ile sosyo-demografik (Örneğin, Frisvoll vd., 2016), algılanan değer (Örneğin, Lee ve Song, 2013), memnuniyet (Örneğin Jang vd., 2014), motivasyon (Kim ve Eves, 2012), deneyim (Quan ve Wang, 2004) davranışsal niyet (Chi vd., 2013) gibi değişkenlerle olan ilişkisi araştırılmıştır. ...
Article
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Local foods reach consumers in two ways: (1) Menus prepared with local foods are consumed by consumers in food and beverages businesses. (2) Local foods are bought by consumers from local markets, farm shops, food cooperatives and farmers' markets. There are many variables that cause these two behaviors, which are an important part of the tourist experience. The discovery of these variables has led to an important academic background in tourism. For this reason, the purpose of study is to examine the local food consumption and purchasing behaviors of tourists separately and to evaluate the variables affecting these behaviors with sample studies. Firstly, this paper reviews the existing literature on local food, then examines the local food consumption and purchasing behaviors of tourists within the context of these variables. In the conclusion of the study, existing studies about tourists' consumption and purchasing behaviors of local foods were examined and suggestions were presented. In the conclusion part of the study, the existing studies about the local food consumption and purchasing behaviors of tourists were examined and suggestions were presented.
... 18 In the past decades, the genetic ability to perceive the bitter taste of thiourea compounds, such as 6-npropylthiouracil (PROP) and phenylthiocarbamide (PTC), has gained considerable attention as a paradigm of general taste perception and an oral marker of food preferences and physiological mechanisms. 17,19,20 This statement is based on several findings that have shown that individuals who only perceive PROP at high concentrations or not at all also perceive lower bitterness of other bitter compounds 21,22 and lower sweetness, 23 sourness, 24 pungency, 25 astringency, 26 umami taste, 27 fats, 28 and high-energy foods when compared with those who perceive PROP as more bitter. 29 Typically, they show a higher acceptance of fruits, vegetables, 30,31 and strong-tasting or high-fat foods. ...
Article
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Background: The few studies that evaluated taste function in Parkinson's disease (PD) showed inconsistent results. The inherited ability to taste the bitter compound of 6‐n‐propylthiouracil has been considered to be a paradigm of general taste perception. 6‐n‐propylthiouracil taste perception is mediated by the TAS2R38 receptor, and reduced 6‐n‐propylthiouracil sensitivity has been associated with several diseases not typically related to taste function. Objectives: We evaluated the 6‐n‐propylthiouracil taste perception and the TAS2R38 gene as genetic risk factors for the development of idiopathic PD in PD patients and healthy controls (HC). Methods: The 6‐n‐propylthiouracil taste perception was assessed by testing the responsiveness, and the ability to recognize, 6‐n‐propylthiouracil and sodium chloride. The participants were classified for 6‐n‐propylthiouracil taster status and genotyped for the TAS2R38 gene. Results: A significant increase in the frequency of participants classified as 6‐n‐propylthiouracil nontasters and a reduced ability to recognize bitter taste quality of 6‐n‐propylthiouracil were found in PD patients when compared with healthy controls. The results also showed that only 5% of PD patients had the homozygous genotype for the dominant tasting variant of TAS2R38, whereas most of them carried the recessive nontaster form and a high number had a rare variant. Conclusions: Our results show that 6‐n‐propylthiouracil taster status and TAS2R38 locus are associated with PD. The 6‐n‐propylthiouracil test may therefore represent a novel, simple way to identify increased vulnerability to PD. Moreover, the presence of the nontasting form of TAS2R38 in PD may further substantiate that disease‐associated taste disruption may represent a risk factor associated with the disease. © 2018 International Parkinson and Movement Disorder Society
... So, attention to tiny entities involved in conferring taste is not proper to the post-war period or even to the twentieth century. What is distinct is the extent to which the molecular register has become legible (measurable through experimental equipment and techniques), quantifiable (as a presumably universal means of comparison), and authoritative (entrenched in social, financial, and material infrastructure) in the study of taste and smell since roughly the 1970s (Bartoshuk 1993;de Chadarevian and Kamminga 1998, 1;Delwiche 1996;Collings 1974). Also distinct is the extent to which the molecular register is engaged tactically to access not primarily the health of the eater, but their pleasure (Roosth 2013;Tracy 2016). ...
Article
Since the closing decades of the twentieth century, molecular techniques of mapping chemosensation (the chemical senses of taste and smell) have been woven into a universalizing, evolutionary explanation for human eating behavior. In a prominent example, umami (translated from Japanese as “savory deliciousness”) has come to be understood as the “fifth basic taste sensation,” elicited by the common flavor enhancer monosodium glutamate (MSG) along with other amino acids and ribonucleotides. Meanwhile, socialized associations of food desirability, undesirability, pleasure, and disgust have likewise come to be interrogated on the molecular level—in the oral cavity, in the brain, and throughout the gastrointestinal tract. In this paper, I abridge this molecularization of sensuous eating with the provocation that the sensory is affective is molecular is political. This phrase signals the stakes with which taste and smell are ontologized as fundamentally embedded in memory (and thus in affect and in culture); as conducted in train with corporate food and beverage research and development; and effected at molecular sites of transduction (chemical reception). It is to say that, in recent decades, the sensory and affective domains have been made molecular. And in the context of food science, that molecular knowledge is interested. This paper conducts a brief, critical accounting of how chemosensation is made knowable and actionable, and for what purposes. It suggests that the most authoritative knowledge of how taste and smell mediate human health (the sensory) is shaped by the corporate imperative to determine what chemical compounds humans register as pleasurable (the affective), and thus what food products humans can be relied upon to buy (the political). As a result, a lack of scientific consensus on wider questions of metabolism—of glutamate, for instance—is built into chemosensory science, which has privileged the work of product design.
... Thus the reported areas of taste perception did not always match the known locations of true taste sensors. This disparity between the true taste loci and the perceived sensitive areas could be explained in part by illusion or touch (Bartoshuk 1993). Taste perceptions are localized not only to the sites of taste buds, but also to areas touched in the mouth (Todrank and Bartoshuk 1991). ...
Article
Umami is the term that identifies the taste of substances such as L-glutamate salts, which were discovered by Ikeda in 1908. Umami is an important taste element in natural foods; it is the main taste in the Japanese stock “dashi,” and in bouillon and other stocks in the West. The umami taste has characteristic qualities that differentiate it from other tastes, including a taste-enhancing synergism between two umami compounds, L-glutamate and 5′-ribonulceotides, and a prolonged aftertaste. The key qualitative and quantitative features of umami are reviewed in this paper. The continued study of the umami taste will help to further our general understanding of the taste process and improve our knowledge of how the taste properties of foods contribute to appropriate food selection and good nutrition.
... Regarding sweetness, it has been evidenced that although fructose and glucose content are well correlated, they do not drive the perception of sweetness because of a mixture suppression effect (Watrelot et al., 2016). It has been described that sweetness affects the perception of astringency and bitterness (Bartoshuk, 1993). In red wines, the addition of saccarose suppresses the maximum intensity of astringency perceived (Valentová et al., 2002). ...
Book
Phenolic compounds are a large family of metabolites that result from the secondary metabolism of plants. Novel insights about phenolic chemical structure, analytical methods, therapeutic effects, sensory properties, viticultural practices to modify their content and the use of these compounds found in agro-industrial wastes have been gathered in this book. A comprehensive overview on phenolic compounds and neurodegenerative disorders, highlighting their antioxidant, anti-inflammatory properties and their effects on Parkinson’s disease have been compiled. In relation to antioxidant properties, the metabolism and bioavailability of several hydroxycinnamic acids present in coffee have been studied in detail, and also the methods to determine antioxidant capacity have been included. Different strategies in order to improve the extraction and determination of phenolic compounds in a complex matrix by analytical techniques are provided, reporting problems and new analytical solutions. The role of these compounds in color stabilization and also in bitterness and astringency perception has been reported. Moreover, the interactions that take place among no volatile and volatile compounds present in wine affecting sensory perception have been briefly introduced. Furthermore, the use of cover crops in vineyards and their effects on agronomical and enological behavior – particularly, their impact on phenolic compounds – have been highlighted. Finally, the biological properties of phenolic compounds from industrial wastes have been tackled, since they are a promising alternative to transform agro-industrial wastes into a source of natural and healthy compounds.
... In the last several decades, numerous studies have focused on the use of the bitter compound, 6-n-propylthiouracil (PROP) and its chemical relative phenylthiocarbamide (PTC), as genetic markers for oral sensations that have downstream effects on food preferences, eating habits, nutritional status and health [1][2][3]. This approach is based on data indicating that PROP taster status is associated with variations in taste perception and preference for a wide range of oral stimuli including other bitter substances [4][5][6][7][8][9], chemical irritants [10,11], sweet substances [12], sour compounds [13], umami taste [14], fats and high-energy foods [15][16][17], compounds which give rise to astringent sensations [18], and fruits and vegetables [19][20][21]. Some studies suggested that PROP-related sensory differences may be extended to the olfactory system [22,23], and that PROP taster status may influence food perception also via aromas or flavors [24,25]. ...
Article
Full-text available
In the last several decades, the genetic ability to taste the bitter compound, 6-n-propyltiouracil (PROP) has attracted considerable attention as a model for understanding individual differences in taste perception, and as an oral marker for food preferences and eating behavior that ultimately impacts nutritional status and health. However, some studies do not support this role. This review describes common factors that can influence the characterization of this phenotype including: (1) changes in taste sensitivity with increasing age; (2) gender differences in taste perception; and (3) effects of smoking and obesity. We suggest that attention to these factors during PROP screening could strengthen the associations between this phenotype and a variety of health outcomes ranging from variation in body composition to oral health and cancer risk.
... Aunque existen experimentos que han logrado inducir la preferencia por este sabor en ratas o chimpancés, los seres humanos son los únicos animales que consumen deliberadamente picante. A numerosas personas de todo el mundo les gusta consumir alimentos que contienen capsaicina, a pesar de su capacidad para provocar molestias, irritación, e incluso dolor (2). ...
... The salty taste of salt (NaCl) in PMPs is mainly due to the Na + cation and the Cl − anion changing the ionic strength of the medium (Bartoshuk, 1993; and thus contributing to the release of aromatic volatile molecules. The characteristic taste of PMPs is traditionally a function of their salt quantity. ...
Article
Currently, there is major consumer concern about dietary salt intake worldwide. However, even with the development of contemporary preservation practices, sodium chloride is still essential in processed meat products. Despite a long history of use, salt is now seriously controversial in food due to health concerns that are mostly related to high blood pressure and cardiovascular risks. Changes in meat processing methods have reduced those potential risks, but different perceptions continue to shape how consumers and society view dietary salt. The current consumer demand for additive‐free food, such as the clean‐label movement, has renewed consumer willingness for naturalness in food products.
... Among T2Rs, TAS2R38 has been widely studied because it mediates the bitter taste of thiourea compounds, such as phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP), which has been reported as an oral marker for individual differences in taste perception, general food preferences and dietary behaviour, with consequent links to body mass composition and other non-tasting physiological mechanisms 1,2,9,13-17 . Several results show that perception of to the bitter taste PTC/PROP is associated with perception of other taste stimuli 13,[18][19][20][21][22][23][24][25] , food preferences and choices 13,[26][27][28][29] . Peculiarly, PROP super-taster individuals, compared to PROP non-tasters, seem ...
Article
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Bitter taste receptors play crucial roles in detecting bitter compounds not only in the oral cavity, but also in extraoral tissues where they are involved in a variety of non‒tasting physiological processes. On the other hand, disorders or modifications in the sensitivity or expression of these extraoral receptors can affect physiological functions. Here we evaluated the role of the bitter receptor TAS2R38 in attainment of longevity, since it has been widely associated with individual differences in taste perception, food preferences, diet, nutrition, immune responses and pathophysiological mechanisms. Differences in genotype distribution and haplotype frequency at the TAS2R38 gene between a cohort of centenarian and near-centenarian subjects and two control cohorts were determined. Results show in the centenarian cohort an increased frequency of subjects carrying the homozygous genotype for the functional variant of TAS2R38 (PAV/PAV) and a decreased frequency of those having homozygous genotype for the non-functional form (AVI/AVI), as compared to those determined in the two control cohorts. In conclusion, our data providing evidence of an association between genetic variants of TAS2R38 gene and human longevity, suggest that TAS2R38 bitter receptor can be involved in the molecular physiological mechanisms implied in the biological process of aging.
... However, we observed a main effect of the PROP taster status on the total taste score and on bitter score, such that taster subjects (super-tasters and medium tasters) had higher scores than non-tasters at each time point. These findings fit with data showing a greater general taste sensitivity in tasters than non-tasters [26][27][28][29][30][31][32]144,145]. ...
Article
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Bariatric surgery is the most effective long-term treatment for severe obesity and related comorbidities. Although patients who underwent bariatric surgery report changes of taste and smell perception, results from sensory studies are discrepant and limited. Here, we assessed taste and smell functions in 51 patients before, one month, and six months after undergoing bariatric surgery. We used taste strip tests to assess gustatory function (including sweetness, saltiness, sourness, umaminess, bitterness and oleic acid, a fatty stimulus), the “Sniffin’ Sticks” test to assess olfactory identification and the 3-Factor Eating Questionnaire to assess eating behavior. We also explored associations between these phenotypes and flavor-related genes. Results showed an overall improvement in taste function (including increased sensitivity to oleic acid and the bitterness of 6-n-propylthiouracil (PROP)) and in olfactory function (which could be related to the increase in PROP and oleic acid sensitivity), an increase in cognitive restraint, and a decrease in disinhibition and hunger after bariatric surgery. These findings indicate that bariatric surgery can have a positive impact on olfactory and gustatory functions and eating behavior (with an important role of genetic factors, such PROP tasting), which in turn might contribute to the success of the intervention.
... Sex differences have been documented among GTS groups, as women are more likely to be supertasters than men (Bartoshuk, Duffy, and Miller 1994). Anatomical differences across GTS are represented in the density of fungiform papillae and taste pores on the anterior tongue, as densities are highest in supertasters, followed by midtasters and nontasters, respectively (Bartoshuk 1993;Bartoshuk, Duffy, and Miller 1994;Essick et al. 2003). GTS manifests in perceptual differences to taste, as supertasters experience heightened responses to stimuli than mid-and nontasters (Dietsch, Westemeyer, et al. 2019;Ko et al. 2000;Nagy, Steele, andPelletier 2014a, 2014b;Pelletier and Steele 2014). ...
Article
Consuming foods and liquids for nutrition requires the coordination of several muscles. Swallowing is triggered and modified by sensory inputs from the aerodigestive tract. Taste has recently received attention as a potential modulator of swallowing physiology, function, and neural activation; additionally, taste impairment is a sequela of COVID-19. This review presents factors impacting taste and swallowing, systematically summarizes the existing literature, and assesses the quality of included studies. A search was conducted for original research including taste stimulation, deglutition-related measure(s), and human participants. Study design, independent and dependent variables, and participant characteristics were coded; included studies were assessed for quality and risk of bias. Forty-eight articles were included after abstract and full-text review. Synthesis was complicated by variable sensory components of stimuli (taste category and intensity, pure taste vs. flavor, chemesthesis, volume/amount, consistency, temperature), participant characteristics, confounding variables such as genetic taster status, and methods of measurement. Most studies had a high risk of at least one type of bias and were of fair or poor quality. Interpretation is limited by wide variability in methods, taste stimulation, confounding factors, and lower-quality evidence. Existing studies suggest that taste can modulate swallowing, but more rigorous and standardized research is needed.
... According to findings showing associations between perceptions for the five taste qualities [19][20][21]23,25,26,[48][49][50]88] and for PROP, our results showed that the scores that the subjects gave to tastes (that are not mediated by specific receptors) were significant features in facilitating the learning of the model to differentiate categories of PROP tasters. ...
Article
Full-text available
Several studies have used taste sensitivity to 6-n-propylthiouracil (PROP) to evaluate interindividual taste variability and its impact on food preferences, nutrition, and health. We used a supervised learning (SL) approach for the automatic identification of the PROP taster categories (super taster (ST); medium taster (MT); and non-taster (NT)) of 84 subjects (aged 18–40 years). Biological features determined from subjects were included for the training system. Results showed that SL enables the automatic identification of objective PROP taster status, with high precision (97%). The biological features were classified in order of importance in facilitating learning and as prediction factors. The ratings of perceived taste intensity for PROP paper disks (50 mM) and PROP solution (3.2 mM), along with fungiform papilla density, were the most important features, and high estimated values pushed toward ST prediction, while low values leaned toward NT prediction. Furthermore, TAS2R38 genotypes were significant features (AVI/AVI, PAV/PAV, and PAV/AVI to classify NTs, STs, and MTs, respectively). These results, in showing that the SL approach enables an automatic, immediate, scalable, and high-precision classification of PROP taster status, suggest that it may represent an objective and reliable tool in taste physiology studies, with applications ranging from basic science and medicine to food sciences.
... The most studied phenotypic marker of genetic variability in the perception of bitter taste is the responsiveness to the 6-n-propylthiouracil (PROP status). Individuals can be classified into three PROP taster groups: non-tasters, medium tasters, and super-tasters, which are also reported to differ in eating behaviour and food preferences [33]. In addition to perceptual factors, there are also psychological factors that influence preferences and choices of healthy food, such as food neophobia, which is the reluctance to eat novel or unknown foods [34]. ...
Article
Tartary buckwheat is a pseudocereal receiving increasing attention as a minor crop interesting for agrobiodiversity conservation and sustainability. It is rich in bioactive substances which, however, may lead to sensory properties undesirable to the consumer, such as bitterness and astringency. The aim was to evaluate consumers' perception and overall liking of food products enriched with tartary or common buckwheat. A total of 120 consumers (56% women) aged 20-60 years (mean age ± SD: 38.8 ± 13.0 years) evaluated six samples of a corn-based gluten-free formulation enriched by increasing concentrations (20%, 30%, 40%) of either common (CB) or tartary buckwheat (TB) flour for overall liking and appropriateness of sensory properties. Results showed significant differences (p < 0.0001) in liking among samples. Considering all subjects, liking decreased with the increase of tartary buckwheat additions, although TB20 and TB30 samples were well accepted and comparable to all CB samples. TB40 was the least liked product. Two clusters of consumers showing opposite behaviours according to liking were found. One cluster (30%) showed an increased liking with the increasing amount of tartary buckwheat. These results show that by keeping the concentration of tartary buckwheat up to 30%, it is possible to develop new products accepted by consumers.
... Several studies pointed out that taste sensitivity might be innate (Duffy & Bartoshuk, 2000;McCorkindale, 1992). Biological variables including genetic factors (Allen, McGeary, & Hayes, 2013;Kim et al., 2004;Perry et al., 2007;Taernwall, Silventoinen, Kaprio, & Tuorila, 2012) and oral anatomy (Bartoshuk, 1993;Miller & Reedy, 1990) do not influence taste sensitivity, providing further evidence that taste sensitivity is innate. The vast majority of studies focused on the influence of physiological, biological and genetic factors on taste sensitivity. ...
Article
Little is known about how sensitivity to trigeminal stimulation such as carbonation is affected by consumption habits and consumer characteristics. The aim of this study was to determine how detection thresholds for and perception of sparkling sensations in carbonated mineral water are affected by frequency of consumption of carbonated water and individual consumer characteristics. One hundred subjects differing in sparkling water consumption frequency (non-consumers, infrequent consumers, frequent consumers) participated. First, sparkling sensation detection thresholds were determined using the method of best estimate threshold (BET) with CO 2 concentrations ranging from 0.03 to 1.05 g/L. Secondly, intensity of sparkling sensation and liking of five sparkling waters (CO 2 concentrations ranging from 0.21 to 4.92 g/L) were assessed. To characterize consumers, consumption frequency of sparkling water, sensitivity to 6-npropylthiouracil (PROP taster status) and consumer characteristics were determined. Average detection threshold of sparkling sensation (BET) was 0.44 g/L CO 2 concentration. BET of sparkling sensation was not affected by consumption frequency of sparkling water and was not related to PROP taster status and consumer characteristics. Perception of sparkling intensity and liking of carbonated mineral water were significantly affected by consumption frequency of sparkling water. Sparkling sensations were perceived significantly more intensive by non-consumers compared to infrequent and frequent consumers. Surprisingly, non-consumers liked sparkling water significantly more than infrequent or frequent consumers. We conclude that consumption frequency of and preferences for carbonated water do not influence detection thresholds of sparkling sensations but influence suprathreshold intensity perception of sparkling sensations in carbonated water.
... To date, much of what is known about the relations between taste perception and diet quality comes from studies that assessed each taste separately, with the majority of work focusing on bitter. In these single taste studies, individuals are often classified as non-tasters, medium tasters, or supertasters, either based on their phenotypic perception of the bitter compounds 6-n-propylthiouracil (PROP) or phenylthiocarbamide (PTC), or their genotype at the Taste 2 Receptor Member 38 (TAS2R38) bitter taste receptor gene (10,11). When related to diet, taster status in adults has been associated with intakes of vegetables (12), sweets (13,14), and alcohol (15), although not consistently (16,17). ...
Article
Background Current approaches to studying relations between taste perception and diet quality typically consider each taste—sweet, salt, sour, bitter, umami—separately or aggregately, as total taste scores. Consistent with studying dietary patterns rather than single foods or total energy, an additional approach may be to study all 5 tastes collectively as “taste perception profiles.” Objective We developed a data-driven clustering approach to derive taste perception profiles from taste perception scores and examined whether profiles outperformed total taste scores for capturing individual variability in taste perception. Methods The cohort included 367 community-dwelling adults [55–75 y; 55% female; BMI (kg/m2): 32.2 ± 3.6] with metabolic syndrome from PREDIMED-Plus, Valencia. Cluster analysis identified subgroups of individuals with similar patterns in taste perception (taste perception profiles); quantitative criteria were used to select the cluster algorithm, determine the optimal number of clusters, and assess the profiles’ validity and stability. Goodness-of-fit parameters from adjusted linear regression evaluated the individual variability captured by each approach. Results A k-means algorithm with 6 clusters best fit the data and identified the following taste perception profiles: Low All, High Bitter, High Umami, Low Bitter & Umami, High All But Bitter and High All But Umami. All profiles were valid and stable. Compared with total taste scores, taste perception profiles explained more variability in bitter and umami perception (adjusted R2: 0.19 vs. 0.63, respectively; 0.40 vs. 0.65, respectively) and were comparable for sweet, salt, and sour. In addition, taste perception profiles captured differential perceptions of each taste within individuals, whereas these patterns were lost with total taste scores. Conclusions Among older adults with metabolic syndrome, taste perception profiles derived via data-driven clustering may provide a valuable approach to capture individual variability in perception of all 5 tastes and their collective influence on diet quality. This trial was registered at https://www.isrctn.com/ as ISRCTN89898870.
... Genetic taster status (GTS) is an inherited relative sensitivity to taste stimulation. It is assessed via chromosomal expression of the TAS2R38 gene (Reed et al., 1999;Bartoshuk, 2000;Kim et al., 2003), density of the fungiform papillae on the tongue (Bartoshuk, 1993;Bartoshuk et al., 1994;Essick et al., 2003), and/or perceptual sensitivity to the bitter compound 6-n-Propylthiouracil (PROP; Bartoshuk, 1991;Smutzer et al., 2013). There are three broad classifications of GTS: nontasters, midtasters, and supertasters (Bartoshuk, 1991). ...
Article
Full-text available
As part of a larger study examining relationships between taste properties and swallowing, we assessed the influence of genetic taster status (GTS) on measures of brain activity and swallowing physiology during taste stimulation in healthy men and women. Twenty-one participants underwent videofluoroscopic swallowing study (VFSS) and functional magnetic resonance imaging (fMRI) during trials of high-intensity taste stimuli. The precisely formulated mixtures included sour, sweet-sour, lemon, and orange taste profiles and unflavored controls. Swallowing physiology was characterized via computational analysis of swallowing mechanics plus other kinematic and temporal measures, all extracted from VFSS recordings. Whole-brain analysis of fMRI data assessed blood oxygen responses to neural activity associated with taste stimulation. Swallowing morphometry, kinematics, temporal measures, and neuroimaging analysis revealed differential responses by GTS. Supertasters exhibited increased amplitude of most pharyngeal movements, and decreased activity in the primary somatosensory cortex compared to nontasters and midtasters. These preliminary findings suggest baseline differences in swallowing physiology and the associated neural underpinnings associated with GTS. Given the potential implications for dysphagia risk and recovery patterns, GTS should be included as a relevant variable in future research regarding swallowing function and dysfunction.
... Generally, sweetness, saltiness, sourness, bitterness, and 'umami' are important elements for food taste. For example, the typical stimuli are sugars (sweetness), sodium chloride (saltiness), hydrochloric acid (sourness), and either caffeine, quinine, or some kind of flavonoid (bitterness) [3][4][5][6]. Among them, bitterness is also an important trait for buckwheat. ...
Article
Full-text available
Buckwheat (Fagopyrum esculentum) is recognized as an important traditional crop in some regions, and its taste is an important characteristic. Of the three cultivated buckwheat species, Tartary buckwheat (Fagopyrum tataricum) and perennial buckwheat (Fagopyrum cymosum) have strong bitterness in their seeds, which has prevented the wider use of the seeds of these varieties. In Tartary buckwheat, some studies have focused on the cause of strong bitterness generation. Tartary buckwheat seeds contain large amounts of the functional compounds rutin and rutinosidase, and rutin hydrolysis by rutinosidase has been found to be the trigger of rutin hydrolysis. Therefore, a variety with only a trace of rutinosidase and with reduced bitterness is required. The rutinosidase in Tartary buckwheat seeds consists of two major isozymes with very similar enzymatic characteristics, which can hydrolyze flour rutin within several minutes after the addition of water. Recently, the trace-rutinosidase variety Manten-Kirari in Tartary buckwheat was developed. The trace-rutinosidase characteristics were dominated by a single recessive gene. In ‘Manten-Kirari’ dough and foods, such as breads, confectionaries, and noodles, the rutin residual ratio was higher and bitterness was reduced compared to that of the normal-rutinosidase variety. In this review, we summarize the detailed research on the breeding of buckwheat related to reducing bitterness and rutin hydrolysis.
... Since taste buds are located mostly on the tongue, the pathological mechanism of oral contact allergy could affect them directly, leading to destruction. 12 Certain areas on the tongue are more sensitive than others to specific tastes 13,14 which may explain why the sour and bitter tastes seem to be the most frequently affected, while the sweet taste was the least affected. Sub-analyses indicate that nickel could be more responsible for reducing the bitter taste, titanium for reducing the salty taste, while both nickel and titanium are equally responsible for the deterioration of a sour taste. ...
Article
Objective To assess the prevalence of allergic sensitization to titanium and nickel in orthodontic patients and to evaluate alterations of smell and taste. Subjects and Methods A total of 250 subjects were invited to participate, 245 accepted. The age range was 11 to 45 years, 68% were females and 52% adolescents. An epicutaneous patch test was performed. Of the positive subjects in the patch test, 26 participated in testing taste and smell and were matched by age and sex with 26 negative subjects. Results The prevalence of hypersensitivity to titanium and/or nickel in orthodontic patients was 15.5%. Taste and smell were more impaired in sensitized subjects (p≤0.025), taste was more affected than smell and the tastes most affected were sour and bitter tastes, while the sweet taste was least impaired. Conclusion The allergic sensitization to titanium is more uncommon than to nickel, with altered smell and taste related to those hypersensitivities.
... Malgré de nombreuses corrections en1974[297] et surtout par les travaux de Linda Bartoshuk[298] en 1993, cette erreur persiste encore aujourd'hui à se répandre dans les écrits. La perception du goût serait en réalité moins segmentée et toutes les papilles, quelle que soit leur localisation, percevraient les goûts primaires. ...
Thesis
Lors de l’élevage des vins avec le bois de chêne, plusieurs molécules d’intérêts organoleptiques comme les ellagitanins (vescalagine, castalagine, roburines A, B, C, D, E et grandinine), sont extraites. Leurs concentrations dans le bois et le vin sont très variables et leurs cinétiques d’extraction au cours de l’élevage ainsi que leurs propriétés organoleptiques dans les vins sont mal connues. Dans le but de classifier chaque douelle pour fabriquer des barriques avec des indices en polyphénols (IP) totaux significativement différents, un système proche infrarouge (NIRS), Oakscan®, a été mis en place par la tonnellerie Radoux. Notre objectif était d’étudier l’influence de ce mode de classifications des bois au niveau de la composition moléculaire et organoleptique des vins. Dans un premier temps, la classification NIRS des bois de chêne a été confirmée par quantification des concentrations en ellagitanins totaux et moléculaire par HPLC-UV-MS. Une forte variabilité des concentrations en ellagitanins des bois est observée entre 5,95 et 32,91 mg d’équivalent acide ellagique/g de bois. De plus, la classification NIRS des bois se corrèle avec les analyses chimiques (p < 0,02%). Cette nouvelle méthode permet donc de fabriquer des barriques avec un IP moyen différent (IP : 11 à 70). Dans un second temps, des vins de différentes origines et cépages sont élevés dans les barriques classifiées. La cinétique des teneurs en ellagitanins montre l’influence de la classification des bois de chêne (p < 5%). En effet, dès les premiers mois d’élevage, une augmentation en ellagitanins jusqu’à un maximum est obtenue. Plus les bois sont riches, plus le maximum de concentration en ellagitanins des vins est élevé et décalé dans le temps. Puis, une lente diminution des concentrations en ellagitanins est observée. Les influences du grain et de la chauffe des bois ont également été analysées. La solubilisation dans les vins des composés aromatiques des bois de chêne classifiés par Oakscan® montre dans plusieurs cas que les teneurs en aldéhydes furaniques et en syringol impliqués dans les perceptions du fumé/grillé sont corrélées avec la classification NIRS et également avec l’IP des bois. Ainsi, un vin élevé au contact de bois riches en polyphénols possède des concentrations en arômes fumé/grillé plus importantes. Néanmoins, l’intensité de la chauffe a un rôle prépondérant sur les concentrations de ces arômes boisés. Parallèlement, les propriétés organoleptiques des vins élevés avec du bois de chêne à 6, 12, 18 ou 24 mois et testées par un jury entrainé, montrent des différences significatives corrélées à l’IP des barriques. Les vins élevés au contact des IP les plus importants sont significativement décrits comme plus boisés, fumés/grillés et épicé au nez. En bouche, l’amertume et l’astringence sont significativement plus importantes pour les vins élevés dans les barriques possédant les plus fortes concentrations en ellagitanins. A contrario, le fruité des vins, au nez et en bouche, est généralement noté comme moins important pour les vins élevés avec des barriques à IP le plus haut.L’influence de la classification des bois, en fonction de leurs grains et de leurs IP, sur la consommation en oxygène des vins rouges a été suivie grâce à une méthode innovante et non invasive. Les résultats montrent que 96% de l’oxygène dans le vin à T0 est consommé huit jours après entonnage. Des différences significatives (p < 0,01%), entre les vitesses de consommation de l’oxygène et l’IP ou le grain des barriques, sont observées. La vitesse de consommation d’oxygène augmente en corrélation de l’IP des barriques ou de la taille du grain. Ces résultats permettent d’envisager l’utilisation de méthodes de sélection non empiriques et fiables des bois de chêne en fonction de leurs grains ou de leurs concentrations en ellagitanins ce qui permet de fabriquer des barriques classifiées à l’aide de nos résultats conférant, au vin, des propriétés organoleptiques maîtrisées.
Article
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Fairly poor data are available on the relationship between taste perception, food preferences and oral microbiota. In the present study, we investigated the hypothesis that subjects with higher responsiveness to 6-n-propylthiuracil (PROP) might be characterized by a different taste sensitivity and tongue microbiota composition. Indeed, the bacterial metabolism may modulate/enhance the concentration of tastants near the taste receptors, modifying taste perception through a sensorial adaptation mechanism or by a broad range of microbial metabolic pathways. The detection thresholds of sweet, sour, salty and bitter, the Fungiform Papillae Density (FPD) and the composition of bacteria lining the tongue were determined in Supertasters (high PROP responsiveness, ST) and Non-tasters (low PROP responsiveness, NT). An important inter-individual variability was found for all taste stimuli and FPD between the two groups, with NT subjects showing significant higher threshold values and a lower FPD than with STs. We found five bacterial genera whose relative abundances were significantly higher in STs than NTs. This study opens new avenues of research by highlighting associations between parameters usually studied independently.
Chapter
Taste and mouthfeel are essential elements of wine quality and major drivers for expert evaluation and consumer liking. Major taste qualities in wine are sweetness, sourness, and bitterness, contributed by different types of molecules, including sugars, organic acids, and ethanol, while mouthfeel encompasses a number of interrelated tactile sensations. The present chapter reviews current knowledge on the compounds and mechanisms responsible for wine taste and mouthfeel properties, with special emphasis on astringency elicited by phenolic compounds, and presents physicochemical and sensory analysis approaches involved in this research. It then includes a discussion on the impact of some viticulture and winemaking practices on wine composition and associated taste and mouthfeel properties.
Article
Taste and olfaction elicit conscious feelings by direct connection with the neural circuits of emotions that affects physiological responses in the body (e.g., heart rate and skin conductance). While sensory attributes are strong determinants of food liking, other factors such as emotional reactions to foods may be better predictors of consumer choices even for products that are equally-liked. Thus, important insights can be gained for understanding the full spectrum of emotional reactions to foods that inform the activities of product developers and marketers, eating psychologist and nutritionists, and policy makers. Today, self-reported questionnaires and physiological measures are the most common tools applied to study variations in emotional perception. The present review discusses these methodological approaches, underlining their different strengths and weaknesses. We also discuss a small, emerging literature suggesting that individual differences and genetic variations in taste and smell perception, like the genetic ability to perceive the bitter compound PROP, may also play a role in emotional reactions to aromas and foods.
Article
This work represents a contribution in the comprehension of a racimic mixture of caffeine-sucrose molecules and their taste-taste interaction, by the use of a binary model expression of non-exclusive competitive extended Hill model. This extended model is deduced by statistical physics treatment. The simulation results suggested that the sucrose molecule formed an aggregate of two molecules and anchored with a non-parallel position onto the human neuroreceptor taste sites. Contrary to the sucrose molecule, the molecule of caffeine is anchored in a parallel position with the human neuroreceptor taste sites. The pore size distribution (PSD) and the adsorption energy distribution (AED) of human neuroreceptor sites are derived through the selected model to describe porosity and energitical homogeneity of taste adsorbent surface. So, the mutual interaction between molecules of racemic mixture dose-response curves of caffeine and sucrose on human neuroreceptor sites. Firstly, this model is used to analyze the taste-taste interaction mechanism of the mixture of bitter caffeine-sweet sucrose taste. Secondly, all these stereo and energetical parameters will be used for an objective description of the taste of the mixture of caffeine-sucrose molecules in the intense and qualitative aspects of the taste of the mixture.
Thesis
The hedonic regulation of eating behavior has been shown to be altered in case of obesity, notably the chemo-sensory functions and the reward system. Although bariatric surgery is the most effective treatment for obesity, patients do not all respond the same way to this treatment and some of them might regain weight after a certain time. It is essential to promote an adapted balanced diet for the long-term weight maintenance of bariatric surgery patients. A better understanding of the postoperative modifications of food choices and preferences will enable clinicians to give personalized nutritional advice in the context of a precision bariatric medicine. This doctoral work aims to advance this knowledge, by responding to four objectives. The first objective was to synthesize the evidence for the link between bariatric surgery in relation to changes in food preferences by a systematic and meta-analytical approach. With an original approach considering various methods to assess food preferences our systemic analysis of the evidence showed a change in food preferences in patients with obesity who undergo bariatric surgery at specific times during their weight loss trajectory. The second objective was to study the links between food preferences, taste, smell and the weight loss success of bariatric surgery. To this aim, we used an online questionnaire in a cohort of bariatric surgery patients. We found that food preferences were different between patients with and without sensory alterations. For those who experienced sensory alterations, there was a decreased preference for unhealthy foods. We also found that food preferences were different between patients in a weight loss success and failure. Of importance, a higher appreciation for green vegetables was associated with a weight loss success. The third objective of this thesis was to adapt and use a behavioral computerized task in a clinical setting, to compare food reward (i.e., ‘liking’ and ‘wanting’) between patients with unoperated obesity, a sleeve gastrectomy and a Roux-en-Y gastric bypass. Our results showed that the Leeds Food Preference Questionnaire could be clinically relevant to identify post-operative alterations in food reward and to guide caregivers to give personalized advice in patients. Especially, we found that ‘liking’ for a large range of food categories was lower among post-operative patients compared to non-operative patients with obesity while ‘wanting’ was lower among post-operative patients for certain food categories only, including highly palatable foods. The fourth objective of this thesis was to develop a protocol to study food preferences after bariatric surgery in a more realistic environment. We designed a study using a buffet meal in an experimental restaurant, which will be used to study differences in terms of diet quality, food intake and microstructure of the meal between patients with obesity, with and without a bariatric surgery. This doctoral work is original as it used a multidisciplinary approach and a diversity of methods to move forward knowledge about the issue of modifications of food preferences in the context of bariatric surgery. It also highlighted the importance of a personalized nutritional strategy for the bariatric surgery patients.
Article
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Oral sensitivity to fats varies in individuals influencing nutritional status and health. Variations in oleic acid perception are associated with CD36 and odorant binding protein (OBPIIa) polymorphisms, and 6-n-propylthiouracil (PROP) sensitivity, which is mediated by TAS2R38 receptor. L-Arginine (L-Arg) supplementation was shown to modify the perception of the five taste qualities. Here we analyzed the effect of three concentrations (5, 10, 15 mmol/L) of L-Arg on oral perception of oleic acid in forty-six subjects classified for PROP taster status and genotyped for TAS2R38, CD36 and OBPIIa polymorphisms. L-Arg supplementation was effective in increasing the perceived intensity of oleic acid in most subjects. The lowest concentration was the most effective, especially in PROP non-tasters or medium tasters, and in subjects with at least an allele A in CD36 and OBPIIa loci. Density Functional Theory (DFT) calculations were exploited to characterize the chemical interaction between L-Arg and oleic acid, showing that a stable 1:1 oleate·ArgH⁺ adduct can be formed, stabilized by a pair of hydrogen bonds. Results indicate that L-Arg, acting as a ‘carrier’ of fatty acids in saliva, can selectively modify taste response, and suggest that it may to be used in personalized dietetic strategies to optimize eating behaviors and health.
Chapter
This chapter examines how taste and flavor help us survive. Omnivores (like humans) face a dilemma; we must select healthy foods and avoid poisons. An early belief in the innate ability to eat a healthy diet (“wisdom of the body”) gave way to our current understanding that taste is the true nutritional sense. A few simple substances (salt, glucose) necessary to solve immediate nutritional problems (sodium deficiency, low blood glucose) produce hard‐wired liking. Most poisons are bitter and we are hard‐wired to dislike them. Food flavor is a combination of taste and retronasal olfaction (odor volatiles perceived from the mouth). Retronasal olfactory stimuli are liked or disliked primarily through association with positive (e.g., calories) or negative (e.g., nausea) biological states. Unfortunately, hard‐wired and acquired liking can lead to nutritional disorders. Taste evolved to help us survive, but can also lead to overeating with attendant health risks.
Article
The non-tasting form of the bitter taste receptor, TAS2R38, has been shown as a genetic risk factor associated with the development of Parkinson's disease (PD). Specific taste receptors that are expressed in the lower gastrointestinal tract may respond to alteration in gut microbiota composition, detecting bacterial molecules, and regulate immune responses. Given the importance of brain-gut-microbiota axis and gene-environment interactions in PD, we investigate the associations between the genetic variants of TAS2R38 and gut microbiota composition in 39 PD patients. The results confirm that the majority of PD patients have reduced sensitivity to 6-n-propylthiouracil (PROP) and are carriers of at least one non-functional TAS2R38 AVI haplotype. Moreover, we found this correlation to be associated with a reduction in bacteria alpha-diversity with a predominant reduction of Clostridium genus. We hypothesised that the high frequency of the non-taster form of TAS2R38 associated with a diminuition of Clostridium bacteria in PD might determine a reduction in the activation of protective signalling-molecules useful in preserving gut homeostasis. This pilot study, by identifying a decrease in specific bacteria associated with a reduced sensitivity to PROP, adds essential information that opens new avenues of research into the association of PD microbiota composition and sensory modification.
Article
Taste information is encoded in the gustatory nervous system much as in other sensory systems, with notable exceptions. The concept of adequate stimulus is common to all sensory modalities, from somatosensory to auditory, visual, and so forth. That is, sensory cells normally respond only to one particular form of stimulation, the adequate stimulus, such as photons (photoreceptors in the visual system), odors (olfactory sensory neurons in the olfactory system), noxious heat (nociceptors in the somatosensory system), etc. Peripheral sensory receptors transduce the stimulus into membrane potential changes transmitted to the brain in the form of trains of action potentials. How information concerning different aspects of the stimulus such as quality, intensity, and duration are encoded in the trains of action potentials is hotly debated in the field of taste. At one extreme is the notion of labeled line/spatial coding - information for each different taste quality (sweet, salty, sour, etc.) is transmitted along a parallel but separate series of neurons (a "line") that project to focal clusters ("spaces") of neurons in the gustatory cortex. These clusters are distinct for each taste quality. Opposing this are concepts of population/combinatorial coding and temporal coding, where taste information is encrypted by groups of neurons (circuits) and patterns of impulses within these neuronal circuits. Key to population/combinatorial and temporal coding is that impulse activity in an individual neuron does not provide unambiguous information about the taste stimulus. Only populations of neurons and their impulse firing pattern yield that information.
Article
An increased incidence of noninfectious chronic diseases, such as obesity, diabetes, and allergies, has been noted in the last century, especially in the last 2 to 3 generations. Evidence suggested that the interrelation among these chronic conditions in pediatric age (e.g., children and adolescents aged 4-16 y) is complex and still unknown, reinforcing the interest of pediatricians in these diseases. Of interest is the need to better understand the link between these pathologies and sensory perception, since the chemical senses of taste and smell, together with chemesthesis, are reported to have a role in food choices and may provide a novel target for intervention in the treatment of these pathologies. This review aims to explore the current evidence on the link between these chronic conditions and chemosensory perception (i.e., taste and smell). In addition, the putative role that chemosensory perception may have on food choices and eating behavior of children and adolescents affected by these diseases are highlighted. Furthermore, the review addresses the unexplored issues that need to be investigated in this area. The literature data search suggested that no clear relation between taste and smell perception and the aforementioned diseases in young population yet exists. However, some possible trends have been highlighted in the adult population, in whom the duration of disease might have affected the relation. There is a need for further, high-quality, hypothesis-led research, with robust measures of taste and smell functions as the primary outcomes, to strengthen or deny this evidence.
Chapter
Food choices are complex decisions that are largely guided not only by perceptions of taste, cost, and convenience but also by consumer concerns about health, safety, and increasingly, the environment. The concept of taste refers to taste, aroma, texture, and the pleasure response to foods. The cost component covers food prices and the relative affordability of alternative food patterns. Convenience refers to ease of physical access to food sources and to the time spent buying and preparing food. The healthfulness of foods has been measured using nutrient density metrics. The environmental cost of food production is increasingly cited as a potential driver of future food choices and a predictor of future diets. While taste is an important driver of food choices, it is not the only one. The current emphasis in public health nutrition is on sustainable food systems and on the adequacy, quality, and, above all, affordability of the global food supply. All too often, good-tasting empty calories are cheap, whereas nutrient-rich foods are more expensive. Public health programs to improve nutrient density of population diets ought to consider taste, cost, and convenience among the key drivers of food choice and food consumption patterns.
Article
This article traces the history of Sensory Science in America. It starts with the roots of psychophysics in nineteenth-century Germany, following from Weber to Fechner to Wundt to Titchener to Boring and finally to SS Stevens. Next it discusses early discrimination testing at Carlsberg Brewery in Denmark and at Seagram Corporation in the USA. A brief history of the start of hedonic testing at the Chicago Quartermaster’s store by David Peryam will be followed by the start of descriptive testing. Specifically, the work by Jean Caul, Herbert Stone, and Joel Sidel, as well as Elaine Skinner and Gail Civille, is covered. Lastly the seminal effect of Rose Marie Pangborn, and especially her Sensory Evaluation of Food Course on sensory science worldwide, is discussed.
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This is a reprint of articles from the Special Issue published online in the open access journal Nutrients (ISSN 2072-6643) (available at: https://www.mdpi.com/journal/nutrients/special_issues/Salt_Taste).
Article
Objectives/Hypothesis Taste sensitivity varies greatly among individuals influencing eating behavior and health, consequently the disorders of this sense can affect the quality of life. The ability to perceive the bitter of thiourea compounds, such as phenylthiocarbamide (PTC), has been largely reported as a marker of the general taste sensitivity, food preferences, and health. PTC sensitivity is mediated by the TAS2R38 receptor and its genetic common variants. We study the role of the TAS2R38 receptor in taste disorders with the aim of understanding if these can be genetically determined. Study Design Prospective cohort study. Methods Differences in the PTC responsiveness between the patients cohort and healthy controls were assessed. All subjects received standardized tests for smell and taste function and were genotyped for the TAS2R38 gene. Results PAV/PAV homozygous patients gave high PTC ratings, whereas PAV/AVI genotypes reported lower values, which are similar to those determined in AVI/AVI or rare genotypes. In addition, the patients cohort did not meet the Hardy‐Weinberg equilibrium at the TAS2R38 locus, showing a very low frequency of subjects carrying the PAV/AVI diplotype. Independently, in healthy controls who were in equilibrium at the locus, PAV/PAV homozygous and heterozygous rated PTC bitterness higher compared to AVI/AVI or rare genotypes. Conclusions Our findings, by showing that an only taster haplotype (PAV) is not sufficient to evoke high responses of TAS2R38 receptor in patients with taste disorders, suggest that the genetic constitution may represent a risk factor for the development of taste disorders. Level of Evidence 2c Laryngoscope, 2019
Chapter
Rozin coined the phrase “the omnivore’s dilemma” to encapsulate what an omnivore must do to survive: avoid toxins and take in nutritious food. This chapter is organized to show what is known about how taste contributes to this biological imperative. We begin with the anatomy and physiology of taste and show how nature uses chemosensory pleasure (liking for beneficial substances and disliking for dangerous ones) to promote survival. One of the most important distinctions for this area is between hard-wired and learned affect. Historically, belief in hard-wired affect has often given way to understanding how learning accomplished what seemed to be hard-wired.
Article
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Individuals are classified as tasters or non-tasters based on their ability to detect the bitterness of PTC&sol;PROP (Phenylthiourea&sol;6- n -propylthiouracil). Sodium benzoate (a food preservative), potassium benzoate taste more bitter to tasters of PTC&sol;PROP than to non-tasters. The tastes of these salts confirm the roles of ions assigned by Beidler [ J. Neurrophysiol. , 16, 595–607 (1953)]. The sodium cation tastes salty. The potassium cation tastes salty and bitter. At low concentrations the benzoate anion inhibits the salty taste of the sodium and potassium cations and the bitter taste of the potassium cation, but at higher concentractions the benzoate anion taste bitter and that bitterness adds to the bitterness of potassium.
Article
Full-text available
Modern psychophysical studies of sensory systems have produced new insight into sensory function and new techniques that have application to the clinical evaluation of taste. Most previous taste evaluation has been done with threshold measures that are subject to a variety of problems and that also fail to provide an accurate picture of suprathreshold sensitivity. The scaling of suprathreshold intensity reflects a patient's taste world more accurately than thresholds.
Article
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Genetic sensitivity to bitter taste may be associated with preference or rejection of some foods by children. Thirty-four children aged 5-7 y participated in the following assessments: a threshold test for 6-n-propylthiouracil (PROP), a scaling test to determine PROP sensitivity above threshold concentrations, a taste test of 11 foods and beverages with two methods of assessing preference (order of food selection and hedonic rating), and a verbally administered food-preference questionnaire. The 30 children who completed these tests successfully were classified as nontasters or tasters based on their PROP thresholds as well as their suprathreshold PROP functions. Analysis of variance showed significant differences in acceptance of cheese and milk for the two taste groups on one of the three preference tasks, selection of foods in order of preference. Tasters selected cheese later than did nontasters, suggesting that they like it less. Tasters selected milk earlier than did nontasters, suggesting that they like it more.
Chapter
Among several claims made concerning genetically determined taste differences in man (Snydeb and Davidson, 1937), only one, the PTC sensitivity, follows a simple Mendelian pattern and the present chapter will predominantly be concerned with this taste polymorphism. Discovered by Fox (1932) it provides the sense physiologist with two kinds of healthy people, both frequent in most populations, who throughout their lives maintain markedly different taste thresholds when challenged by a specific group of “bitter” chemicals. As this difference depends on a single autosomal allelic gene pair and is stationary the polymorphism has also been described as “taste-blindness,” in analogy to the stationary — though sex linked — hereditary defects of colour vision which are commonly described as colour-blindness.
Article
In a series of four assessments, 37 preschool children indicated their liking for a set of fruits by rank ordering the items. Using multidimensional scaling techniques, the salient dimensions underlying the children's preferences were found to be familiarity and sweetness. Assessment II was a replication designed to determine the stability of preferences. The children's preferences were quite stable; the correlation of preference orders of Assessments I and II was. 58. To determine the reliability of the dimensions obtained, new fruits were added to the set in Assessment III. The same dimensions emerged, and the relative placement of the new fruits on each dimension was as predicated. When the data for 3- and 4-year-olds were analyzed separately for Assessments I, II, and III, familiarity accounted for the greatest proportion of the variance in the preferences of 3-year-olds, while sweetness was most salient for 4-year-olds. In an initial attempt to modify preferences, it was found that repeated exposure to one fruit led to increased familiarity but not to an increase in preference for that fruit. The research demonstrated the feasibility of obtaining preference data directly from young children.
Article
A method developed to quantify taste buds in living human subjects to study the relationship between taste sensitivity and taste bud distribution was used to count the taste buds in 10 human subjects; fungiform papillae were mapped in 12 subjects. Taste buds were identified by staining taste pores with methylene blue, and images of the papillae and their taste pores were obtained with videomicroscopy and an image processor. Fungiform papillae showed a 3.3-fold range in density, from 22.1 to 73.6 papillae/cm 2 with an average of 41.1 ± 16.8/cm 2 (s.d., n = 2). There was a 14-fold range in taste pore density, from 36 to 511 pores/cm 2 among subjects, with an average of 193 ± 133/cm 2 (s.d., n = 10). Fungiform papillae contained from 0 to 22 taste pores, with an average per subject of 3.75 ± 1.4 taste pores/papilla (s.d., n = 10). We hypothesize that some differences in human taste sensitivity may be related to these variations in taste bud density.
Article
The taste thresholds for alcoholic solutions of anetholtrithione (ATTH) in a student sample were found to be bimodally distributed. This substance does not contain the NC=S group which until now has been the only one to produce bimodality. Taste sensitivity to ATTH is highly correlated with PTC sensitivity and presumably is largely controlled by the same alleles.
Article
Sensory endings of chorda tympani and lingual (trigeminal) nerve fibers were identified by selective denervation and localized within specific regions of fungiform pipillae in the hamster. The chorda tympani was resected from the middle ear and the peripheral fibers were allowed to degenerate for 1, 3, or 8 days prior to perfusion-fixation and electron-microscopic examination of the anterior tongue. Taste buds were virtually devoid of intact nerves by 3 days following chorda tympani denervation. Remnants of the fibers were restricted to taste buds. Lingual fibers, on the other hand, persist in normal numbers after chorda tympani resection and populate perigemmal areas of connective tissue and extragemmal areas located apically in the squamous, nontaste epithelium surrounding the taste bud. This study provides evidence of a segregation of chorda tympani fibers in the taste bud and lingual nerve fibers in the apical fungiform papilla. The lingual nerve-epithelial arrangement and superficial location, near the least cornified area of the tongue, may be well suited for relatively sensitive somatosensation, possibly mechanoreception. Thus, the apical fungiform papilla appears to be a site where both taste and tactile oral stimuli interact with receptors.
Article
Taste recognition thresholds and psychophysical intensity functions were determined for NaCl, sucrose, QHC1, urea, and citric acid for four loci on the tongue and on the soft palate. The results showed greater differences between loci than previously reported. Contrary to older data, the threshold for bitter was found to be lower for the fungiform papillae at the front of the tongue and for the soft palate than for the vallate papillae. For all compounds, the slopes of the intensity functions varied with the locus of stimulation. The functions for most compounds were steepest at the vallate and foliate loci.
Article
Touching three thermal stimulators with the first, second, and third fingers of the hand revealed the following phenomena: (1) When the outer two stimulators were warm (or cold) and the center stimulator thermally neutral, warmth (or cold) was felt at all three fingers (referral). (2) When all three stimulators were warm (or cold), the magnitude of warmth (or cold) felt at the middle finger was greater than the sensation felt when the center stimulator alone was touched (enhancement). (3) When the thermal qualities of the center and outer stimulators differed, the sensation at the middle finger often took on the quality of the sensation produced at the outer fingers (domination). (4)Synthetic heat was sometimes experienced when the outer stimulators were warmed and the center stimulator cooled. The results raise interesting possibilities concerning the probable role that tactile stimulation plays in thermal localization.
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Thesis (M.D.) - Yale University, 1991. Includes bibliographical references (leaves 41-48).
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Title on spine: Taste illusions : a taste loss explanation. Thesis (M.D.) - Yale University, 1991. Bibliography: leaves 49-51.
Article
The foliate papillae of the rat are dually innervated by the chorda tympani and the glossopharyngeal nerves. The effects of electrical stimulation of the distal end of the cut chorda tympani on the spontaneous discharges and the gustatory responses of the glossopharyngeal nerve fibers were examined in the rat while gustatory stimuli were applied to the foliate papillae. Activities of 5 out of 35 taste units in the glossopharyngeal nerve were influenced by this procedure. Three units showed an inhibitory effect, 1 unit showed an excitatory effect and 1 unit changed its firing pattern. These facts may be derived from alterations of the blood circulation in the vicinity of the taste receptor cells innervated by the glossopharyngeal nerve fibers.
Article
The dual innervation of the foliate papillae of the rat by the chorda tympani and the glossopharyngeal nerves was determined in this electrophysiological study. The magnitude of the chorda tympani response to the chemical stimulation of the foliate papillae was small and variable in different animals. Summated responses of both the chorda tympani and the glossopharyngeal nerves to the stimulation of the foliate papillae showed similar patterns such as long latencies, slowly rising responses after onset of stimulation and slow declines by water ringing. The relative responsiveness to 5 different chemicals applied to the foliate papillae were almost the same for the chorda tympani and the glossopharyngeal nerves. However, these 2 nerves produced different patterns of response to various chemicals applied to the fungiform, foliate and circumvallate papillae.
Article
Four methods for assessing sensitivity to the bitterness of phenylthiocarbamide (PTC) and propylthiouracil (PROP) were compared. Good agreement was found among results from forcedchoice detection thresholds, recognition thresholds, and category ratings of single stimuli. Testing by means of papers impregnated with these compounds led to a high incidence of false positive responses from insensitive subjects. Phenylthiocarbamide was a slightly better discriminator of sensitive from insensitive subjects than was propythiouracil. Category ratings of the intensity of the antimodal PTC threshold concentration are a valid, reliable and efficient screening method. Relative safety in the use of PTC and PROP is discussed.
Article
Temporal bitterness sequences elicited by four equi-bitter concentrations of caffeine and quinine were evaluated by a time – intensity procedure. For both compounds, the increase in bitterness intensity was highly correlated with an increased duration of aftertaste, although the time to maximum intensity did not change. For equi-bitter solutions, the duration of aftertaste was influenced by the specific tastant, and was longer for caffeine. Caffeine elicited a faster maximum rate of onset and slower maximum rate of decay of bitterness. Only one significant difference between subjects who were sensitive to l-phenyl-2-thiourca (PTC) and those who were non-tasters was found. Tasters rated the maximum intensity of quinine solutions higher than non-tasters.
Article
Several investigators have studied the relationship between innate, individual, differences in sensitivity to PTC-type compounds and the perception of threshold and suprathreshold concentrations of a wide range of tastants. Some authors reported taste perception differed between ‘tasters’ and ‘non-tasters’; others demonstrated no significant differences. The present study investigated whether an individual's PROP-sensitivity affects perception of KCl, NaCl and quinineHCl. The PROP-threshold concentrations for 60 subjects were determined using the method of limits. Two 20-subject contrast groups were selected to participate in the main experiment. Here, perceived bitterness, saltiness, and total taste intensity were assessed on 150 mm visual analogue scales. The two taster-groups did not differ in their perception of KCl, NaCl, or quinineHCl. It is hypothesized that the significant differences in the perception of PTC-unrelated compounds between ‘tasters’ and ‘non-tasters’ reported by other investigators may, in part, be the result of errors during the classification procedure and of inappropriate methods of statistical analysis.
Article
Thiourea tasters and nontasters did not significantly differ in their ratings of intensity of caffeine or quinine HCl, but significant group × concentration interactions were noted for denatonium benzoate, sucrose octaacetate and urea.
Article
‘Tasters’ and ‘nontasters’ of the bitter compound, 6-n-propylthiouracil, were asked to judge the taste intensity of various compounds and the loudness of a 1000 Hz tone. Differences between tasters and nontasters in their suprathreshold magnitude estimates of sweet-tasting compounds, in particular, were examined with two different stimulation methods (front, dorsal-surface flow and whole mouth ‘sip and spit’) and with two different procedures for putting data onto a common intensity scale. With the first procedure, data were normalized to the strongest salt used (1.0 M NaCl) under the assumption that salt is equally intense to tasters and nontasters. Since differences in perceived taste intensity between these two groups were under investigation, the second normalization procedure used the assumption that tasters and nontasters have similar perceptions of loudness. This application of a new cross-modal matching technique suggests that the perceived sweetness of sucrose, neohesperidin dihydrochalcone, and saccharin is more intense to tasters than to nontasters.
Sensory evaluation has recently utilized the methods developed by psychophysicists and psychometricians, who week to represent data in terms of various scales and mathematical formulations. This review covers the development of ratio scaling to develop relations between sensory and instrumental measures of food, the use of multivariate psychophysical procedures which relate a variety of physical variables to a single sensory response, and the use of multidimensional scaling to relate different sensory percepts to each other. Each of these approaches is nascent in applications to sensory evaluation, although the mathematics and formulations are very developed. Each approach gives the experimenter insights into subjective and objective correlations and the manner in which the panelist perceives relations among stimuli. The treatment of the reported literature for each approach follows the same course: necessary conditions for its application to sensory evaluation, experiences with model systems and real foods, and potential uses and limitations in sensory evaluation.
Article
Bitter taste thresholds for 6-n-propylthiouracil are bimodally distributed, dividing subjects into tasters and nontasters. Their taste worlds differ with regard to the sweetness of sucrose and saccharin and to the bitterness of saccharin. These differences suggest that nontasters tend to perceive less bitterness in saccharin at concentrations used in beverages.
Article
Measured the taste thresholds of 10 undergraduates sensitive to the bitter substance phenylthiourea or phenylthiocarbamide (PTC), designated "tasters," and 10 less sensitive Ss, designated "nontasters" or "taste blind." Thresholds were measured for 5 compounds: PTC, QHCl, urea, caffeine, and NACl. Ss sorted the substances, presented in decreasing concentrations, into 2 groups, those with taste and those without, and assigned numbers proportional to the perceived intensity of the stimuli. For both groups of Ss, thresholds for both PTC and caffeine showed bimodal distribution, and caffeine thresholds were correlated with PTC thresholds (r = .83, p < .001). None of the other substances produced these results. These and other findings are discussed as they relate to other studies and to problems of multiple taste receptor sites, sensory coding, and taste sensitivity to caffeine. (17 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
The pontine taste area relays gustatory information from the rostral pole of the solitary nucleus to both the thalamus and ventral forebrain. An electrophysiological investigation of this area was carried out in 3 stages. First, multiunit responses from the dorsal pons were mapped using sapid, thermal, and tactile stimuli applied to the anterior tongue. The gustatory zone lies within and just dorsal and ventral to the brachium conjunctivum as it enters the pons from the cerebellum. Second, gustatory stimuli were applied independently to the anterior and posterior tongue to determine whether receptors in both fields are represented in the pons. Responses with characteristics similar to those obtained from the glossopharyngeal nerve were located on the dorsal edge of the pontine gustatory zone. More ventrally the responses from the posterior tongue mimicked anterior tongue responses, but were of lesser amplitude than the largest anterior responses occurring at the ventral edge of the gustatory zone. Third, 71 single units were isolated in the dorsal pons, and tested for sensitivity to gustatory stimulation of the anterior and posterior tongue separately. More than half the units responded to gustatory stimuli--some from the anterior tongue alone, some from the posterior alone, but most responded to stimuli applied to either field. In the latter instance 7 of 10 units tested continued to respond after anesthetizing the chorda tympani with Xylocaine instilled into the middle ear, thus demonstrating a true glossopharyngeal input. This proves that gustatory information from two distinct receptive fields may converge on the same central neuron.
Article
Individuals differ in their hedonic response to sweet: sweet likers show increasing liking with increasing sucrose concentration, while sweet dislikers show increasing dislike with increasing concentration. Our results indicated that naive raters can correctly classify sweet likers and dislikers by observing subjects' facial responses to the taste of sucrose. Also, for both adults and children, the sweet liker/disliker distinction correlated strongly with the genetically determined ability to taste 6-n-propylthiouracil (PROP): PROP nontasters were almost always sweet likers, whereas sweet dislikers were almost always PROP tasters. Sweet dislikers also reported a purer sweet sensation than likers, who perceived nonsweet components in pure sucrose solutions. These results suggest that the sweet liker/disliker distinction is robust and valid, and that sensitivity to PROP may influence preference for sweet by altering the quality of sweet.
Article
Fifty-five young adult subjects and their parents were classified as alcoholic or nonalcoholic based on a standardized questionnaire (the MAST) filled out by the subjects. Subjects' thresholds for detection of 6-n-propylthiouracil (PROP; a PTC-like compound) were determined with the experimenter blind to MAST responses. There was a significantly higher proportion of nontasters of PROP among children of alcoholics than among children of nonalcoholics. There was no relationship between the child's alcoholism status and ability to taste PROP. These results are inconsistent with the view that excessive use of alcohol causes the association between nontasting and alcoholism and are consistent with the view that there is a genetic association between PROP/PTC-tasting and alcoholism.
Article
Taste sensations appear to come from all over the inner surface of the mouth, yet the taste receptors are restricted to relatively small particular areas of the oral surface. In addition, even if a relatively large (e.g., one half) proportion of the taste field is damaged, subjective taste experience may be unaffected. The touch system contributes to this constancy because taste sensations appear to be localized by touch. If a taste solution is painted from the side of the tongue (an area of low receptor density) past the tip (an area of high receptor density) and on to the second side, the taste sensation begins weak, gets stronger at the tip, and retains much of its intensity. The strong taste from the tip follows the tactile path of the stimulus sweep. This illusion occurs for all four stimuli tested: sucrose, sodium chloride, citric acid, and quinine hydrochloride.
Article
The desensitization resulting from application of 10 or 100 ppm capsaicin was investigated, using daily testing of a capsaicin series (1-1000 ppm, in log steps). The series showed a significant decrement in perceived burn following desensitization with either concentration. Perceived burn of 100 and 1000 ppm did not recover from 100 ppm desensitization in six days, and perceived burn of 1-1000 ppm did not recover from 100 ppm desensitization in six days. When single capsaicin concentrations, rather than the series, were tested at one, two, four, or six days after desensitization, 10 ppm recovered from 10 ppm desensitization in one or two days, and 100 ppm recovered from 100 ppm desensitization between two and four days. This suggests that daily testing with the capsaicin series delayed recovery from desensitization. Nontasters of 6-n-propylthiouracil rated capsaicin burn lower than did tasters. The application method of rolling capsaicin onto the tongue with a swab was found to transiently inhibit burn. Implications for ingesting capsaicin products are discussed.
Article
A technique for fitting mixture distributions to phenylthiocarbamide (PTC) sensitivity is described. Under the assumptions of Hardy-Weinberg equilibrium, a mixture of three normal components is postulated for the observed distribution, with the mixing parameters corresponding to the proportions of the three genotypes associated with two alleles A and a acting at a single locus. The corresponding genotypes AA, Aa, and aa are then considered to have separate means and variances. This paper is concerned with estimating the parameters of the model, and their standard errors, by using an application of the EM algorithm. This technique also caters for the fact that the sensitivity measurements are only known to lie between the endpoints of certain intervals and that the exact measurement of the attribute is not possible.
Article
Recent work on the excitatory action of capsaicin on somatic and visceral afferent neurones shows that depolarization is selective for C-fibre polymodal nociceptor afferents and involves opening a non-selective cation channel. Exposure to significantly suprathreshold amounts of capsaicin causes permanent degeneration of C-fibre afferents in adult rats. Functional changes in rats (hypalgesia, diminished neurogenic inflammation) are likely to be a direct consequence of the loss of C-fibre nociceptors, and so are the reductions in neuropeptide levels that follow adult capsaicin treatment. Clinical trials of topical capsaicin treatment for post-herpetic neuralgia have yielded promising results. The selective nature of the action of capsaicin in reducing just C-nociceptor activity may make it particularly useful for treating pain states triggered by C-fibre input.
Article
Although the anatomy of centrifugal input to gustatory neural structures has been described, little is known of the physiological mechanisms that convey this influence or of their functional significance. As a first step in the investigation of these issues, the effect of a reversible lesion in the gustatory neocortex (GN) on the neural code for taste in the parabrachial nucleus of the pons (PbN) was studied in rats. Electrophysiological responses to taste stimuli bathed over the tongue were recorded from single units in the PbN before, after and following recovery from an infusion of procaine-HCl into the GN. Test stimuli consisted of sapid solutions of NaCl (0.1 M), HCl (0.01 M), sucrose (0.5 M), Na-saccharin (0.004 M) and quinine-HCl (0.01 M). Infusions of procaine into the GN were correlated with both specific and nonspecific effects on the responsivity to gustatory stimuli in the PbN. Specific effects included: (1) changes in the magnitude of response to some tastants, but not others, in a given PbN unit, (2) changes in the across unit patterns produced by sweet stimuli and (3) the appearance of OFF responses in a subset of PbN units. Nonspecific effects were evidenced by changes in the spontaneous rates of activity and by enhancement or suppression of responses across all the tastants tested in a subset of PbN units. Comparison of these results with reports on the effects of decerebration suggests that some of these effects may be accounted for by interruption of the descending input from the GN to the PbN. In addition, the stimulus-specific effects that were noted following procaine infusion into the GN provide support for the suggestion that the GN specifically modifies the electrophysiological patterns that are evoked by salient taste stimuli.
Article
Some variations in human taste sensitivity may be due to different numbers of taste buds among subjects. Taste pores were counted on the tongue tips of 16 people with videomicroscopy, and the subjects were divided into two groups (N = 8) by the rank order of their taste bud densities. The "higher" density group averaged 374 +/- 134 taste pores/cm2, while the "lower" density group averaged 135 +/- 43 tp/cm2. The higher density group had an average fungiform papilla density which was 1.8 times greater than the lower density group and an average of 1.5 times more taste pores/papilla. The subjects also rated the intensity for 4 suprathreshold concentrations of 5 taste stimuli placed on the same region of the tongue where taste pores were counted. The group with higher taste bud densities gave significantly higher average intensity ratings for sucrose (196%), NaCl (135%) and PROP (142%), but not for citric acid (118%) and quinine HCl (110%) than the lower density group. Thus, the subjects with higher fungiform taste bud densities also reported some tastes as more intense than subjects with fewer fungiform taste buds.
Article
Eight topical agents in current use were studied for their effects on wound contraction and rate of reepithelialization of full-thickness excisions using a porcine animal model. The following agents were applied daily for a period of 27 days: scarlet red ointment, benzoyl peroxide lotion, bacitracin ointment, silver sulfadiazine cream, aloe vera gel, tretinoin cream, capsaicin cream, and mupirocin ointment. The rate of reepithelialization was significantly enhanced by treatment with capsaicin, bacitracin, silver sulfadiazine, and scarlet red, and was markedly retarded by treatment with tretinoin. Wound contraction was significantly retarded by mupirocin, bacitracin, and silver sulfadizine. Knowledge of the effects of topical agents on various aspects of healing allows the clinician to choose the most appropriate material to use in a given clinical situation to optimize the healing process and produce the best final result.
Article
Uncontrolled studies have indicated that topically applied capsaicin may be a safe and effective treatment for postherpetic neuralgia. In a double-blind study 32 elderly patients with chronic postherpetic neuralgia were treated with either capsaicin cream or its vehicle for a 6-week period. Response to treatment was evaluated by visual analogue scales of pain and of pain relief, together with changes in a categoric pain scale and in a physician's global evaluation. Significantly greater relief in the capsaicin-treated group compared with vehicle was observed for all efficacy variables. After 6 weeks almost 80% of capsaicin-treated patients experienced some relief from their pain. Because capsaicin avoids problems with drug interactions and systemic toxicity, we suggest that topical capsaicin be considered for initial management of postherpetic neuralgia.
Article
Research has shown that gustatory afferents innervating different areas of the oral cavity converge onto single neurons in the nucleus tractus solitarii (NTS). However, most studies of gustatory physiology have only stimulated the receptors on the anterior tongue. No information exists on the responses of hamster NTS neurons to stimulation of receptors located in other areas of the oral cavity. The present investigation compared responses of hamster NTS neurons to stimulation of receptors on the anterior tongue and posterior oral cavity, and to stimulation of both receptor populations together. Of the neurons, 64% responded to both anterior tongue and posterior oral cavity stimulation. The remaining neurons responded exclusively to stimulation of one area. Cells responsive to both fields of stimulation were found throughout the rostral NTS. Cells responding to stimulation of only one field were anatomically separate. Most neurons (69%) were more responsive to anterior tongue than posterior oral cavity stimulation. The neural responses to stimulation of both fields simultaneously were complex. Frequently, a cell's response was intermediate between those produced by stimulation of either receptor population alone. In other cases the response was the same as the larger of the two individual responses. The breadth of responsiveness to the 4 basic taste stimuli (sucrose, NaCl, HCl and quinine-HCl) was similar for both receptor populations, but the breadth of tuning of an individual cell for one field of stimulation was not correlated with its breadth of responsiveness for the other. In contrast, the breadth of tuning following stimulation of the entire oral cavity was correlated with that following stimulation of the anterior tongue.
Article
Separate taste examinations of each area of gustatory innervation are necessary in clinical practice in treating patients with taste disorders. We have developed our own electrogustometer with a dB scale and qualitative and quantitative clinical gustometry using filter-paper discs (the filter-paper disc method). this paper reports on our main basic studies in this field and new insights and experience gained in connection with the two gustometry procedures. Reference is made to the gustatory pathway, innervation area on the tongue and the soft palate, the argument against the localization theory of taste, the correlation between electrogustometry and the filter-paper disc method, differential diagnosis of taste disorders using both methods and the effective use of these methods in clinical practice. The effective use of both methods of measurements is important to give the physician assurance and confidence in the diagnosis and treatment of taste disorders.
Article
The preterminal branching pattern of nerve fibers from the chorda tympani nerve was examined in the tongues of rats using a normal silver stain. The lingual branch of the trigeminal nerve was sectioned unilaterally proximal to where it is joined by the chorda tympani and these fibers were allowed to degenerate from eight to ten days prior to sacrifice of the animals. Termination of the chorda tympani fibers in the anterior tongue was found to be limited to the taste bud region of the fungiform papillae. The control side of the tongue showed ubiquitous fiber terminations in the basal layers of the common epithelium of the filiform papillae as well as in the lateral walls of the fungiform papillae. These fibers were assumed to be of trigeminal origin. Seventy-nine percent of the fungiform papillae on the experimental side of the tongue received fibers from a branched nerve bundle. Branch points within the nerve bundles were located deep within the tongue 300–500 μ below the taste bud in 43% of the papillae, at the base of 36% of the fungiform papillae about 125 μ below the taste bud, and within the papilla.These data corroborate electrophysiological observations that single chorda tympani fibers receive input from more than one taste bud. Lateral inhibition observed among adjacent taste buds has been postulated to result from interaction of fiber inputs at branch points in the afferent fiber. From a theoretical consideration of the morphology of chorda tympani nerve fibers it is concluded that modification of the neural response may be feasible at branch points.
Article
The receptive field (RF) of 67 taste and 85 mechanoreceptive neurons in the solitary tract nucleus (NTS) were located in the oral cavity in albino rats. All of the taste and most (62.4%) of the mechanoreceptive neurons examined had an RF on the ipsilateral side of the tongue and/or the palate. Regardless of whether they were solitario-parabrachial relay (SP) neurons or non-SP neurons, RFs of taste neurons were found on the anterior as well as the posterior tongue. But there were some differences in the RF distribution between the SP and non-SP mechanoreceptive neurons. Most of the mechanoreceptive SP neurons (9 of 11) had an RF on the tongue, while ca. half of the mechanoreceptive non-SP neurons (43 of 79) had an RF on the tongue and palate, but the rest had an RF on other tissue. Most of the neurons studied had a small restricted RF, but complex RFs, e.g. two separate RFs on the tongue, were found in a relatively small number of neurons (four taste and five mechanoreceptive neurons). An inhibitory RF, usually in a remote place from the excitatory RFs, was found in four mechanoreceptive neurons but no inhibitory RFs for taste neurons. Electrical stimulation of the epithelium in the RF with a low current of short duration evoked a few spikes in most units. Two of the three units, giving rise to a vigorous response to taste stimulation, but having single restricted RFs on the anterior tongue, produced a train of spikes lasting more than 20 ms in response to electrical stimulation of the RF.(ABSTRACT TRUNCATED AT 250 WORDS)