The examination of fatty acid taste with edible strips

A novel method for encapsulating nutritional supplements within edible films

Many nutritional supplements are hydrophobic solids or oils that are extremely difficult to administer in tablet form. These supplements are often consumed as large soft gels that may represent a choking hazard. In addition, many nutritional supplements produce an aversive taste or tactile response when consumed orally. Because of these limitations, improved delivery methods for administering nutritional supplements to the oral cavity represent an important goal. In this study, vitamin E acetate is exploited as a model nutritional supplement for developing an improved oral delivery method by encapsulating this vitamin within rapidly dissolving edible films. Vitamin E acetate was solidified by mixing this oil with a long-chain fatty alcohol. The resulting wax was then pulverized and added to an aqueous polymer solution that included melted gelatin. The mixture was then sonicated to form a stable emulsion that was dried to a thin, flexible film. Vitamin E acetate was successfully encapsulated within films at amounts that approximated the minimum daily requirement for this supplement. Minimal loss of this vitamin occurred when the emulsion was dried to a film. Average film thickness was 150 µm, and the encapsulated vitamin E was not degraded. Film formulations that included the excipients sucralose and peppermint oil produced taste intensity ratings in the moderate range, and displayed favorable hedonic responses. In summary, rapidly dissolving edible films have been developed that greatly increase the load capacity of a hydrophobic oral supplement. These edible films represent a promising approach for delivering hydrophobic oils or solids to the oral cavity at bioavailable amounts.

Perception, regulation, and effects on longevity of pollen fatty acids in the honey bee, Apis mellifera

For successful cross-pollination, most flowering plants rely on insects as pollinators and attract them by offering rewards, predominantly nectar and pollen. Bees-a highly important pollinator group-are especially dependent on pollen as their main source of essential nutrients, including proteins, lipids, and sterols. Fatty acids (FAs) in particular play a pivotal role as fundamental energy source, contributing to membrane structure integrity, cellular homeostasis, and cognitive processes. However, overconsumption of FAs can have detrimental effects on fitness and survival. Thus, bees need to precisely modulate FA intake. To better understand how Apis mellifera, the globally predominant managed pollinator, regulate FA intake, we conducted controlled feeding experiments with newly hatched honey bee workers by providing pollen with different FA concentrations. We additionally investigated the honey bee's capacity to perceive individual FAs by means of chemotactile proboscis extension response (PER) conditioning. We tested both natural concentrations and concentrations exceeding those typically found in pollen. Given the dose-dependent importance of FAs observed in other bee species, we hypothesized that (i) a high FA concentration in pollen would reduce honey bee longevity, and (ii) honey bees are able to perceive individual FAs and differentiate between different FA concentrations via antennal sensation prior to consumption. Our study revealed that elevated FA concentrations in pollen resulted in reduced consumption rates and increased mortality in Apis mellifera. Workers can detect and discriminate between saturated and unsaturated FAs utilizing their antennae. Moreover, they were able to distinguish between individual FAs and also between different concentrations of the same FAs. Our results suggest a high sensitivity of A. mellifera towards both the concentration and composition of individual FAs, which greatly impacts their foraging decisions and fitness. These insights contribute to the growing evidence highlighting the importance of balanced nutrient ratios, in particular of FAs, for bees and other organisms.

The gustin gene variation at rs2274333 and PROP taster status affect dietary fat perception: a stepwise multiple regression model study

Gustin, a trophic factor for taste bud development, and its polymorphism at rs2274333 influence taste perception of 6-n-propylthiouracil (PROP) and fungiform papillae (FP) density. The PROP taster status affects dietary fat sensing and body composition. However, there is a paucity of research on the gustin genotype with dietary fat perception, PROP tasting ability, and body mass index (BMI). Thus, taste sensitivity to fat and bitterness was evaluated in 178 healthy individuals. The general labeled magnitude scale was used to determine suprathreshold taste intensity ratings, whereas the alternative forced choice approach was used to estimate the taste-sensing ability. The FP density was assessed by applying blue-colored food dye over the anterior region of the tongue. Restriction fragment length polymorphism was used to detect the genetic polymorphism (rs2274333) in the carbonic anhydrase VI (CA-VI) gene. Fisher's chi-square analysis showed that the CA-VI genotype and allelic frequencies significantly correlated (p<0.001) with the PROP taster status and BMI. Healthy individuals with AA genotypes of the CA-VI polymorphism and PROP super-tasters demonstrated stronger gustatory sensitivity for linoleic acid (LA) with greater FP density in comparison to individuals with AG/GG genotypes and other PROP taster groups. Stepwise forward multiple regression analysis indicates that BMI and PROP taster status significantly influence the LA sensing ability. The suprathreshold intensity rating for LA was also significantly impacted by PROP taster status and CA-VI genotypes, with a variation of 73.3%. Overall, our findings show a relationship between the taste papillae environment and the CA-VI genetic mutation at rs2274333, which influenced the gustatory preference for dietary fat and bitter taste.

Emotional responses to taste and smell stimuli: Self-reports, physiological measures, and a potential role for individual and genetic factors

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.

Molecular and Genetic Factors Involved in Olfactory and Gustatory Deficits and Associations with Microbiota in Parkinson's Disease

Deficits in olfaction and taste are among the most frequent non-motor manifestations in Parkinson’s disease (PD) that start very early and frequently precede the PD motor symptoms. The limited data available suggest that the basis of the olfactory and gustatory dysfunction related to PD are likely multifactorial and may include the same determinants responsible for other non-motor symptoms of PD. This review describes the most relevant molecular and genetic factors involved in the PD-related smell and taste impairments, and their associations with the microbiota, which also may represent risk factors associated with the disease.

How bitter taste influences nutrition and health in primary care

Sensitivity to bitter tastes has a genetic basis which is partly mediated by the TAS2R3 gene. Existing research on how this gene influences dietary habits and successful strategies for encouraging the incorporation of additional fruits and vegetables into individuals’ diets is discussed. We propose that knowledge of a patient's status TAS2R3 genotype could help physicians develop personalized nutritional strategies using exposure and associative conditioning techniques to encourage optimal nutrition.

Genetic Background of Taste Perception, Taste Preferences, and Its Nutritional Implications: A Systematic Review

Background: The rise in nutrition-related morbidity and mortality requires public health intervention programs targeting nutritional behavior. In addition to socio-economical, socio-cultural, psychological determinants, taste is one of the main factors that influence food choices. Differences in taste perception and sensitivity may be explained by genetic variations, therefore the knowledge of the extent to which genetic factors influence the development of individual taste preferences and eating patterns is important for public policy actions addressing nutritional behaviors. Our aim was to review genetic polymorphisms accounting for variability in taste and food preferences to contribute to an improved understanding of development of taste and food preferences.

Methods: The electronic databases PubMed, Scopus, and Web of Science were searched using MeSH in PubMed and free text terms for articles published between January 1, 2000 and April 13, 2018. The search strategy was conducted following the PRISMA statement. The quality of the included studies was assessed by the validated Q-Genie tool.

Results: Following the PRISMA flowchart, finally 103 articles were included in the review. Among the reviewed studies, 43 were rated to have good quality, 47 were rated to have moderate quality, and 13 were rated to have low quality. The majority of the studies assessed the association of genetic variants with the bitter taste modality, followed by articles analyzing the impact of polymorphisms on sweet and fat preferences. The number of studies investigating the association between umami, salty, and sour taste qualities and genetic polymorphisms was limited.

Conclusions: Our findings suggest that a significant association exists between TAS2R38 variants (rs713598, rs1726866, rs10246939) and bitter and sweet taste preference. Other confirmed results are related to rs1761667 (CD36) and fat taste responsiveness. Otherwise further research is essential to confirm results of studies related to genetic variants and individual taste sensitivity. This knowledge may enhance our understanding of the development of individual taste and related food preferences and food choices that will aid the development of tailored public health strategy to reduce nutrition-related disease and morbidity.

General Decrease of Taste Sensitivity Is Related to Increase of BMI: A Simple Method to Monitor Eating Behavior

BACKGROUND AND OBJECTIVES

The present study was conducted to evaluate the relationship between taste identification ability and body mass index (BMI) by studying the response to the administration of different taste stimuli to both sides of the tongue in three different groups of subjects.

SUBJECTS AND METHODS

Thirty healthy normal-weight volunteers, 19 healthy overweight subjects, and 22 obese subjects were enrolled. For each subject, the lateralization Oldfield score, body weight, height, and blood pressure were determined. The taste test is based on filter paper strips soaked with 4 taste stimuli presented at different concentrations to evoke 4 basic taste qualities (salty, sour, sweet, and bitter); pure rapeseed oil and water were also administered to evoke fat and neutral taste qualities. The stimuli were applied to each side of the protruded tongue. Subjects were asked to identify the taste from a list of eight descriptions according to a multiple choice paradigm.

RESULTS

The results showed a general lowering of taste sensitivity with the increase of BMI, except for the taste of fat with rapeseed oil as the stimulus. Other variables affecting taste sensitivity are age (negative association), gender (women generally show higher sensitivity), and taste stimuli concentration (positive association).

CONCLUSIONS

Our findings could provide important insights into how new therapies could be designed for weight loss and long-term weight maintenance and how diets could be planned combining the correct caloric and nutritional supply with individual taste preferences.

Human Tongue Electrophysiological Response to Oleic Acid and Its Associations with PROP Taster Status and the CD36 Polymorphism (rs1761667)

The perception of fat varies among individuals and has also been associated with CD36 rs1761667 polymorphism and genetic ability to perceive oral marker 6-n-propylthiouracil (PROP). Nevertheless, data in the literature are controversial. We present direct measures for the activation of the peripheral taste system in response to oleic acid by electrophysiological recordings from the tongue of 35 volunteers classified for PROP taster status and genotyped for CD36. The waveform of biopotentials was analyzed and values of amplitude and rate of potential variation were measured. Oleic acid stimulations evoked positive monophasic potentials, which represent the summated voltage change consequent to the response of the stimulated taste cells. Bio-electrical measurements were fully consistent with the perceived intensity during stimulation, which was verbally reported by the volunteers. ANOVA revealed that the amplitude of signals was directly associated, mostly in the last part of the response, with the CD36 genotypes and PROP taster status (which was directly associated with the density of papillae). The rate of potential variation was associated only with CD36, primarily in the first part of the response. In conclusion, our results provide direct evidence of the relationship between fat perception and rs1761667 polymorphism of the CD36 gene and PROP phenotype.

Toward Improving Medication Adherence: The Suppression of Bitter Taste in Edible Taste Films

Bitter taste is aversive to humans, and many oral medications exhibit a bitter taste. Bitter taste can be suppressed by the use of inhibitors or by masking agents such as sucralose. Another approach is to encapsulate bitter tasting compounds in order to delay their release. This delayed release can permit the prior release of bitter masking agents. Suppression of bitter taste was accomplished by encapsulating a bitter taste stimulus in erodible stearic acid microspheres, and embedding these 5 µmeter diameter microspheres in pullulan films that contain sucralose and peppermint oil as masking agents, along with an encapsulated masking agent (sucralose). Psychophysical tests demonstrated that films which encapsulated both quinine and sucralose produced a significant and continuous sweet percept when compared to films without sucralose microspheres. Films with both quinine and sucralose microspheres also produced positive hedonic scores that did not differ from control films that contained only sucralose microspheres or only empty (blank) microspheres. The encapsulation of bitter taste stimuli in lipid microspheres, and embedding these microspheres in rapidly dissolving edible taste films that contain masking agents in both the film base and in microspheres, is a promising approach for diminishing the bitter taste of drugs and related compounds.

Effect of chemical interaction between oleic acid and L-Arginine on oral perception, as a function of polymorphisms of CD36 and OBPIIa and genetic ability to taste 6-n-propylthiouracil

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.

Orosensory detection of bitter in fat-taster healthy and obese participants: Genetic polymorphism of CD36 and TAS2R38

BACKGROUND & AIMS

We assessed orosensory detection of a long-chain fatty acid, linoleic acid (LA), and a bitter taste marker, 6-n-propylthiouracil (PROP), and correlated lipid-taster subjects with PROP detection and polymorphism in genes encoding bitter and lipid taste receptors, respectively, TAS2R38 and CD36, in normal weight and obese subjects.

DESIGN

The normal weight (n = 52, age = 35.3 ± 4.10 years, BMI = 23.22 ± 1.44 kg/m²) and obese (n = 52, age = 35.0 ± 5.43 years, BMI = 34.29 ± 5.31 kg/m²) participants were recruited to determine fat and bitter detection thresholds. The genomic DNA was used to determine single nucleotide polymorphism (SNP) of CD36 (rs1761667) and TAS2R38 (rs1726866 and rs10246939).

RESULTS

The study included the participants who could detect LA, i.e., lipid-tasters. There was a positive correlation between BMI and detection thresholds for fat and bitter taste in normal weight and obese subjects. Obese participants showed a positive correlation between LA and PROP detection thresholds. PROP detection thresholds were higher for CD36 SNP (rs1761667) and TAS2R38 SNPs (rs1726866 and rs10246939) in obese participants compared to normal weight subjects. LA detection thresholds were not high for CD36 SNP (rs1761667) or TAS2R38 SNP (rs1726866 and rs10246939) in obese participants.

CONCLUSIONS

Orosensory detection thresholds for fat and bitter taste are associated with BMI, and CD36 and TAS2R38 genotypes are not always associated with taste phenotypes.

The influence of oral processing, food perception and social aspects on food consumption: a review

Eating is an essential activity to get energy and necessary nutrients for living. While chewing, the food is broken down by the teeth and dissolved by saliva. Taste, flavour and texture are perceived during chewing and will contribute to the appreciation of the food. The senses of taste and smell play an important role in selecting nutritive food instead of toxic substances. Also visual information of a food product is essential in the choice and the acceptance of food products, whereas auditory information obtained during the chewing of crispy products will provide information on whether a product is fresh or stale. Food perception does not just depend on one individual sense, but appears to be the result from multisensory integration of unimodal signals. Large differences in oral physiology parameters exist among individuals, which may lead to differences in food perception. Knowledge of the interplay between mastication and sensory experience for groups of individuals is important for the food industry to control quality and acceptability of their products. Environment factors during eating, like TV watching or electronic media use, may also play a role in food perception and the amount of food ingested. Distraction during eating a meal may lead to disregard about satiety and fullness feelings and thus to an increased risk of obesity. Genetic and social/cultural aspects seem to play an important role in taste sensitivity and food preference. Males generally show larger bite size, larger chewing power and a faster chewing rhythm than females. The size of swallowed particles seems to be larger for obese individuals, although there is no evidence until now of an 'obese chewing style'. Elderly people tend to have fewer teeth and consequently a less good masticatory performance, which may lead to lower intakes of raw food and dietary fibre. The influence of impaired mastication on food selection is still controversial, but it is likely that it may at least cause adaptation in food choice. Systemic conditions, such as high blood pressure, diabetes and cancer, with or without medicine use, tend to be associated with taste and chewing alterations. However, definite conclusions seem hard to reach, as research protocols vary largely.

Controversies in fat perception

Nutritional fat is one of the most controversial topics in nutritional research, particularly against the background of obesity. Studies investigating fat taste perception have revealed several associations with sensory, genetic, and personal factors (e.g. BMI). However, neuronal activation patterns, which are known to be highly sensitive to different tastes as well as to BMI differences, have not yet been included in the scheme of fat taste perception. We will therefore provide a comprehensive survey of the sensory, genetic, and personal factors associated with fat taste perception and highlight the benefits of applying neuroimaging research. We will also give a critical overview of studies investigating sensory fat perception and the challenges resulting from multifaceted methodological approaches. In conclusion, we will discuss a multifactorial approach to fat perception to gain a better understanding of the underlying mechanisms that cause varying fat sensitivity which could be responsible for overeating. Such knowledge might be beneficial in new treatment strategies for obesity and overweight.

No Difference in Perceived Intensity of Linoleic Acid in the Oral Cavity between Obese and Nonobese Individuals

Findings from studies examining interactions between fat taste and dietary fat intake or body weight are mixed. A convenience sample of 735 visitors to the Denver Museum of Nature & Science ≥8 years old rated the taste intensity of edible taste strips impregnated with varying concentrations (%v/v) of linoleic acid (LA) (blank = 0.0, low = 0.06, medium = 0.15, high = 0.38). Percent body fat (BF%) was measured using bioelectrical impedance. Fat taste intensity was rated as significantly different across all concentrations (P < 0.001) except between the blank and low concentrations (P = 0.1). Ratings increased monotonically across concentrations. Children (<18 years; N = 180) rated all concentrations as more intense than adults (P < 0.001 for all). Women and girls rated the highest concentration as more intense than men and boys (P < 0.02 for all). BF% was not correlated with fat taste intensity ratings. Self-reported dietary intake indicated that obese individuals’ intensity ratings for medium and high concentrations of LA were inversely related to recent mono- and poly-unsaturated fat exposure (r = −0.19 to −0.27; P < 0.03 for all). No such associations were observed in the nonobese group. Findings suggest that factors other than simple adiposity status influence fat taste intensity ratings, and that participants in fat taste studies should receive standardized meals prior to testing.

A Study on Prevalence of Phenyl Thiocarbamide (PTC) Taste Blindness Among Obese Individuals

INTRODUCTION

Taste blindness to the phenylthiocarbamide (PTC) is an inherited trait that is shown to influence our food and dietary preferences which in turn influence our body weight. Obesity is a global epidemic issue known to be on rise among the developing countries. Relating taste perception to obesity, the present study was undertaken to assess the prevalence of phenylthiocarbamide (PTC) taste blindness among obese individuals.

MATERIALS AND METHODS

Three hundred and fifty individuals of age group 20-40 y were recruited from the local community for the present cross sectional study. Anthropometric measurements were taken and BMI was calculated. Subjects were classified as underweight, normal, overweight and obese based on their BMI. Normal, overweight and obese individuals were then asked to taste the commercially available PTC test papers and classified as non tasters and tasters of PTC.

RESULTS

Out of 350 individuals, mean age group of 30±6.02 y, based on their BMI they were divided into 4 groups, Group A-underweight (16%), Group B-normal (35%), Group C-overweight (28%) and Group D-obese (21%) individuals. In group B, 28% were non tasters of PTC and 65% were tasters. In group C, 82% were non tasters and 13% were tasters and in Group D, 81% were non tasters and 19% were tasters of PTC. The PTC non taster phenotype individuals showed higher BMI as compared with the tasters' phenotype.

CONCLUSION

Exploring the novel connections between taste perception and obesity would help us to gain a control over the global epidemic-Obesity, which is the crux factor for various other health problems. The study advocates the usage of PTC tasting as a reliable indicator of weight gain susceptibility.

Recent advances in fatty acid perception and genetics

This article summarizes new knowledge about the contribution of genetic variation to person-to-person differences underlying some sensory aspects of dietary fatty acids. Receptors on the taste cells of the human tongue arise from genes that have marked variation in DNA sequence, which, in some cases, is associated with differences in how these lipids in foods are perceived. These perceptual differences may affect food selection.

Associations between orosensory perception of oleic acid, the common single nucleotide polymorphisms (rs1761667 and rs1527483) in the CD36 gene, and 6-n-propylthiouracil (PROP) tasting

Orosensory perception of dietary fat varies in individuals, thus influencing nutritional status. Several studies associated fat detection and preference with CD36 or 6-n-propylthiouracil (PROP) sensitivity. Other studies have not confirmed the latter association. We analyzed the relationship between orosensory perception of oleic acid, two CD36 variants, and PROP tasting. Thresholds of oleic acid perception were assessed in 64 subjects using a modification of the three-alternative forced-choice procedure. Subjects were classified for PROP taster status and genotyped for TAS2R38 and CD36 (SNPs: rs1761667 and rs1527483). Subjects homozygous for GG of the rs1761667 polymorphism showed higher sensitivity to oleic acid than AA subjects. The capability to detect oleic acid was directly associated with TAS2R38 or PROP responsiveness. PROP non-tasters had a lower papilla density than tasters, and those with genotype GG of the rs1761667 polymorphism had lower oleic acid thresholds than PROP non-tasters with genotype AA. In conclusion, results showed a direct association between orosensory perception of oleic acid and PROP tasting or rs1761667 polymorphism of CD36, which play a significant role in PROP non-tasters, given their low number of taste papillae. Characterization of individual capability to detect fatty acids may have important nutritional implications by explaining variations in human fat preferences.

Genetic sensitivity to the bitter taste of 6-n-propylthiouracil (PROP) and its association with physiological mechanisms controlling body mass index (BMI)

Taste sensitivity to the bitter compound 6-n-propylthiouracil (PROP) is considered a marker for individual differences in taste perception that may influence food preferences and eating behavior, and thereby energy metabolism. This review describes genetic factors that may contribute to PROP sensitivity including: (1) the variants of the TAS2R38 bitter receptor with their different affinities for the stimulus; (2) the gene that controls the gustin protein that acts as a salivary trophic factor for fungiform taste papillae; and (3) other specific salivary proteins that could be involved in facilitating the binding of the PROP molecule with its receptor. In addition, we speculate on the influence of taste sensitivity on energy metabolism, possibly via modulation of the endocannabinoid system, and its possible role in regulating body composition homeostasis.

Mechanisms and effects of "fat taste" in humans

Evidence supporting a "taste" cue from fat in the oral cavity continues to accrue. The proposed stimuli for fat taste, non-esterified fatty acids (NEFA), are released from food through hydrolytic rancidity and lipase activity derived from foods or saliva. NEFA must then be released from the food matrix, negotiate the aqueous environment to reach taste cell surfaces, and interact with receptors such as CD36 and GPR120 or diffuse across cell membranes to initiate a taste signal. Knowledge of these processes in non-gustatory tissues should inform understanding of taste responses to NEFA. Additionally, downstream effects of oral triglyceride exposure have been observed in numerous studies. Data specific to effects of NEFA versus triglyceride are scarce, but modified sham feeding trials with triglyceride document cephalic phase responses including elevations in serum lipids and insulin as well as potential, but debated, effects on gut peptides, appetite, and thermogenesis. In this review, we highlight the mechanisms by which NEFA migrate to and interact with taste cells, and then we examine physiological responses to oral fat exposure.

A preference test for sweet taste that uses edible strips

A novel delivery method is described for the rapid determination of taste preferences for sweet taste in humans. This forced-choice paired comparison approach incorporates the non-caloric sweetener sucralose into a set of one-inch square edible strips for the rapid determination of sweet taste preferences. When compared to aqueous sucrose solutions, significantly lower amounts of sucralose were required to identify the preference for sweet taste. The validity of this approach was determined by comparing sweet taste preferences obtained with five different sucralose-containing edible strips to a set of five intensity-matched sucrose solutions. When compared to the solution test, edible strips required approximately the same number of steps to identify the preferred amount of sweet taste stimulus. Both approaches yielded similar distribution patterns for the preferred amount of sweet taste stimulus. In addition, taste intensity values for the preferred amount of sucralose in strips were similar to that of sucrose in solution. The hedonic values for the preferred amount of sucralose were lower than for sucrose, but the taste quality of the preferred sucralose strip was described as sweet. When taste intensity values between sucralose strips and sucralose solutions containing identical amounts of taste stimulus were compared, sucralose strips produced a greater taste intensity and more positive hedonic response. A preference test that uses edible strips for stimulus delivery should be useful for identifying preferences for sweet taste in young children, and in clinical populations. This test should also be useful for identifying sweet taste preferences outside of the lab or clinic. Finally, edible strips should be useful for developing preference tests for other primary taste stimuli and for taste mixtures.

Validation of edible taste strips for assessing PROP taste perception

A novel delivery method is described that incorporates taste stimuli into edible strips for determining n-propylthiouracil (PROP) taster status. Edible strips that contained 400 or 600 nanomoles of PROP were prepared for psychophysical studies. Using these strips, we measured taste intensity, taste hedonics, and taste quality responses in a sample of healthy volunteers (n = 118). Participants were also asked to assess a single NaCl strip, a quinine strip, 3 NaCl solutions, and 3 PROP solutions. All psychophysical data were subsequently analyzed as a function of TAS2R38 genotype. The use of PROP strips for distinguishing between individuals with at least 1 PAV allele and individuals with other genotypes was assessed and compared with the use of PROP solutions for making this same distinction. For the 2 PROP strips and PROP solutions, individuals who expressed at least 1 PAV allele could perceive the bitter taste of PROP. Individuals who expressed 2 AVI alleles responded similarly to 400 nanomole PROP strips and blank strips. Furthermore, individuals with 2 AVI alleles responded to 0.032 and 0.32 mM PROP solutions at intensities that were similar to water, though intensity ratings to 3.2 mM PROP solution exceeded water. In general, those with at least 1 PAV allele rated the bitter taste of PROP as unpleasant in both delivery methods (strips or solutions). Psychophysical data from PROP strips and solutions were consistent with TAS2R38 genotype. These results support the validity of edible taste strips as a method for assessing PROP taste perception in humans.

Functionality of fatty acid chemoreception: a potential factor in the development of obesity?

Excess dietary fat consumption is recognized as a strong contributing factor in the development of overweight and obesity. Understanding why some individuals are better than others at regulating fat intake will become increasingly important and emerging associative evidence implicates attenuated fatty acid sensing in both the oral cavity and gastrointestinal (GI) tract in the development of obesity. Functional implications of impaired fatty acid chemoreception include diminished activation of the gustatory system, the cephalic response and satiety. This review will focus on knowledge from animal and human studies supporting the existence of oral fatty acid chemoreception including putative oral detection mechanisms, and how sensitivity to fatty acids is associated with fat consumption and fatty food preference.