Taste Detection Thresholds Research Articles

Evaluation of Oregano (Lippia berlandieri) Essential Oil and Entomopathogenic Fungi forVarroa destructorControl in Colonies of Honey Bee,Apis mellifera

Potential of organic compounds to control Varroa destructor Anderson & Trueman, on honey bee, Apis mellifera L. colonies was evaluated at Cuauhtémoc, Chihuahua, México (28°26′53″N, 106°49′46″W). Treatments were 1.16, 1.33, and 1.50 ml of oregano pure oil (carvacrol 60%); a mixture of oregano oil (7, 8, and 9% carvacrol) with canola oil (v/v); and as a biological control agent, native strains of Beauveria bassiana and Metarhizium anisopliae (108 CFU/g). The efficacy of organic compounds and biological agents was compared with that of amitraz (1%) to eliminate mites from infested colonies of honey bees. In two assays, amitraz was significantly (P < 0.01) the most effective acaricide, with a mean efficacy of 97% in eliminating V. destructor from infested honey bee colonies. However, the most effective organic compound after amitraz in killing V. destructor was 1.16 and 1.5 ml of oregano pure oil, with efficacies of 57 to 74% (P < 0.01). Results suggested that oregano pure oil should be considered a viable alternative to synthetic acaricides for controlling V. destructor in honey bee colonies. The amount of carvacrol in honey produced by bees treated with oregano essential oil did not exceed the taste detection threshold of 0.1 ppm, and therefore, did not pose a risk of taste modification of natural honey.

Contributory role of sex differences in the variations of gustatory function.

Remarkable variability between males and females occurs for an array of taste-guided behaviors in both rodents and humans. Sex differences have been noted for taste preference, detection thresholds, and reactivity to taste stimuli. Manipulating sex hormones during early postnatal development or altering the amount of circulating estrogen in adulthood can dramatically alter the pattern of these behaviors. Receptors for sex hormones appear to be prominent in several nuclei associated with central gustatory pathways, indicating that steroid hormones may modulate central taste processing. Electrophysiological recordings from the rat brainstem suggest that taste-elicited activity to sweet stimuli is organized by hormones during early development, and activity during bitter stimulation is altered by circulating ovarian hormones. Sex differences in gustatory function appear to emerge at the level of the taste bud. Among ovariectomized rats, estradiol treatment decreases activity in the chorda tympani nerve during NaCl stimulation. Although there is no evidence that chorda tympani responses to NaCl differ between intact male and female rats, glossopharyngeal nerve responses are lower in intact females for both NaCl and sodium acetate. Responses in the glossopharyngeal nerve to citric acid stimulation are also higher in female rats relative to males. These findings suggest that, in addition to differential central modulation of taste input based on sex, taste information from the periphery varies between males and females. Although the extent of sex differences in taste processing and the underlying causal mechanisms require further clarification, it is clear that studying one sex alone provides an incomplete picture of gustatory function. © 2016 Wiley Periodicals, Inc.

Taste detection and recognition thresholds in Japanese patients with Alzheimer-type dementia.

Alzheimer-type dementia (AD) is pathologically characterized by massive neuronal loss in the brain, and the taste cortex is thought to be affected. However, there are only a few reports regarding the gustatory function of AD patients, and the conclusions of this research are inconsistent. This prospective study enrolled 22 consecutive patients with mild to moderately severe Alzheimer-type dementia (AD) with mean age of 84.0 years, and 49 elderly volunteers without dementia with mean age of 71.0 years as control subjects. The control subjects were divided into two groups according to age: a younger group (N=28, mean age: 68.5) and an older group (N=21, mean age: 83.0). The gustatory function was investigated using the filter paper disc method (FPD) and electrogustometry (EGM). The gustatory function as measured by the FPD was significantly impaired in patients with AD as compared with age-matched control subjects; no such difference was found between the younger and the older control groups. On the other hand, as for the EGM thresholds, there were no differences between the AD patient group and the age-matched controls. The FPD method demonstrated decreased gustatory function in AD patients beyond that of aging. On the other hand, EGM thresholds did not differ between the AD patient group and the age-matched controls. These results suggest that failure of taste processing in the brain, but not taste transmission in the peripheral taste system, occurs in patients with AD.

The influence of a high-fat meal on fat taste thresholds

A high-fat diet for four weeks has been shown to attenuate fat taste sensitivity in healthy weight individuals. However, there is minimal evidence as to whether a single high-fat meal immediately prior to fat taste threshold testing has an effect on thresholds. Therefore, the aim of the study was to determine the effect of a high-fat meal immediately prior to detection threshold testing for oleic acid (C18:1). Thirty-two participants (15 males, 17 females, aged 39.1 ± 3.1 years, Body Mass Index 23.1 ± 0.7 kg/m2) attended three laboratory sessions. In each session, participants were randomly assigned to one of three different types of breakfast: a high-fat (60% energy from fat), or low-fat (20% energy from fat) or macronutrient balanced (33% energy from fat) frittata. Fat taste thresholds were evaluated using ascending forced choice triangle tests on two occasions each day; once one-hour post breakfast and then one-hour post the completion of the first threshold test. There was no effect of breakfast type on fat taste detection thresholds for the first testing session of each day (P = 0.288), or the second testing session of each day (P = 0.754). There was also no effect of breakfast within each day (day 1: P = 0.198, day 2: P = 0.199, day 3: P = 0.125). There was no effect of macronutrient composition on the ability of participants to rank the level of fat in food (P = 0.345), or preference for the level of fat in food (P = 0.187–0.868). This study provides preliminary evidence that the composition of the meal consumed by a participant immediately prior to testing does not affect fat taste thresholds.

Reliability of a Simple Method for Determining Salt Taste Detection and Recognition Thresholds.

The aim of this study was to assess the reliability of a rapid analytical method to determine salt taste detection and recognition thresholds based on the ASTM E679 method. Reliability was evaluated according to criterion of temporal stability with a 1-week interval test-retest, with 29 participants. Thresholds were assessed by using the 3-AFC technique with 15 ascending concentrations of salt solution (1-292 mM, 1.5-fold steps) and estimated by 2 approaches: individual (geometric means) and group (graphical) thresholds. The proportion of agreement between the test and retest results was estimated using intraclass coefficient correlations. The detection and recognition thresholds calculated by the geometric mean were 2.8 and 18.6mM at session 1 and 2.3 and 14.5mM at session 2 and according to the graphical approach, 2.7 and 18.6mM at session 1 and 1.7 and 16.3mM at session 2. The proportion of agreement between test and retest for the detection and recognition thresholds was 0.430 (95% CI: 0.080-0.680) and 0.660 (95% CI: 0.400-0.830). This fast and simple method to assess salt taste detection and recognition thresholds demonstrated satisfactory evidence of reliability and it could be useful for large population studies.

Sensory Threshold Studies of Picrocrocin, the Major Bitter Compound of Saffron.

This study is part of a wider project on the bitter taste of saffron and its preparations. A deeper knowledge on the taste perception of picrocrocin is necessary in order to develop products that satisfy consumer senses and provide them with adequate amounts of saffron major constituents, also appreciated for bioactivity. A systematic approach on the bitterness of picrocrocin, the major responsible compound, was conducted. A panel was trained specifically for the determination of taste detection and recognition thresholds of picrocrocin, which were found to be 5.34 and 7.26 mg/L, respectively, using the Ascending Forced Choice of Limits methodology. The threshold values were examined in water in absence and presence of other saffron constituents and ethanol and were found to decrease when served hot (61 ± 4 °C). Bitterness was enhanced in 40% (v/v) aqueous ethanol. In both aqueous and ethanol extracts, the presence of saffron volatiles improved bitterness perception. The usefulness of the study was tested in the case of commercial saffron based infusions.

Taste Detection Thresholds of Resveratrol

Resveratrol is a polyphenol that is associated with numerous health benefits related to heart disease, cancer, diabetes, and neurological function. The addition of this compound to food products would help to deliver these health benefits to the consumer. However, bitterness associated with resveratrol may impart negative sensory qualities on the food products into which resveratrol is added; thus, decreasing consumer acceptability. This concern may be resolved by encapsulating resveratrol through spray drying, an innovative processing technique. The objectives of this research were to (1) compare taste detection thresholds of unencapsulated resveratrol and encapsulated resveratrol and (2) determine if the inclusion of anhydrous milk fat in the formulation of the encapsulation wall material affects the taste detection threshold of resveratrol within the microcapsules. Resveratrol microcapsules were produced by encapsulating resveratrol in a protein matrix through spray drying. R-index measure by the rating method was used to determine the average taste detection threshold and the pooled group taste detection threshold. The average and pooled group taste detection thresholds of unencapsulated resveratrol, sodium-caseinate-based resveratrol microcapsule without fat (SC), and sodium-caseinate-based resveratrol microcapsule with fat (SCAMF) were 90 and 47 mg resveratrol/L (unencapsulated), 313 and 103 mg resveratrol/L (SC), 334 and 108 mg resveratrol/L (SCAMF), respectively. The findings demonstrate that the encapsulation of resveratrol decreased the detection of the compound and provided a means to incorporate resveratrol into food products without imparting negative sensory properties.

Disruption in the Relationship between Blood Pressure and Salty Taste Thresholds among Overweight and Obese Children

BackgroundPrevalence of high blood pressure among American children has increased over the past 2 decades, due in part to increasing rates of obesity and excessive dietary salt intake. ObjectiveWe tested the hypothesis that the relationships among blood pressure, salty taste sensitivity, and salt intake differ between normal-weight and overweight/obese children. DesignIn an observational study, sodium chloride (NaCl) and monosodium glutamate (MSG) taste detection thresholds were measured using the Monell two-alternative, forced-choice, paired-comparison tracking method. Weight and blood pressure were measured, and salt intake was determined by 24-hour dietary recall. Participants/settingChildren aged 8 to 14 years (N=97; 52% overweight or obese) from the Philadelphia, PA, area completed anthropometric and blood pressure measurements; 97% completed one or both thresholds. Seventy-six percent provided valid dietary recall data. Testing was completed between December 2011 and August 2012. Main outcome measuresNaCl and MSG detection thresholds, blood pressure, and dietary salt intake. Statistical analysesOutcome measures were compared between normal-weight and overweight/obese children with t tests. Relationships among outcome measures within groups were examined with Pearson correlations, and multiple regression analysis was used to examine the relationship between blood pressure and thresholds, controlling for age, body mass index z score, and dietary salt intake. ResultsNaCl and MSG thresholds were positively correlated (r[71]=0.30; P=0.01) and did not differ between body weight groups (P>0.20). Controlling for age, body mass index z score, and salt intake, systolic blood pressure was associated with NaCl thresholds among normal-weight children (P=0.01), but not among overweight/obese children. All children consumed excess salt (>8 g/day). Grain and meat products were the primary source of dietary sodium. ConclusionsThe apparent disruption in the relationship between salty taste response and blood pressure among overweight/obese children suggests the relationship may be influenced by body weight. Further research is warranted to explore this relationship as a potential measure to prevent development of hypertension.

Differences in taste detection thresholds between normal-weight and obese young adults

Conclusion: Compared with normal-weight individuals, obese young adults exhibited a significantly higher taste threshold for salty taste. Smoking also affected taste functions in this population. Objective: The aim of this study was to investigate the differences in taste detection thresholds between normal-weight and obese young adults. Methods: Taste threshold was measured using electrogustometry (EGM) and chemically with sucrose, NaCl, citric acid, and quinine hydrochloride in 41 volunteers in their twenties, 23 with body mass index (BMI) <23 kg/m2 (normal-weight group) and 18 with BMI >25 kg/m2 (obese group). Results: BMI was significantly higher in the obese than in the normal-weight group (p < 0.05). The obese group exhibited significantly higher EGM thresholds than the normal-weight group on the right (p < 0.05) and left (p < 0.05) posterior tongue. In chemical taste tests, the obese group had higher thresholds for sweet, salty, sour, and bitter tastes than the normal-weight group, although the difference in threshold was significant only for salty taste (p < 0.05). Smoking had an impact on taste threshold, with smokers having higher thresholds than non-smokers, with significantly higher EGM thresholds on the right anterior and posterior and the left anterior tongue (p < 0.05 each).

Abstract 18991: Salt Taste Detection and Recognition Thresholds - Reliability of a Rapid Sensory Analysis Method

Introduction: Excessive sodium intake is clearly and independently associated with hypertension and cardiovascular diseases. The salt taste sensitivity is closely related to hedonic aspects of nutrition, and this is an important individual factor contributing to the nutritional behavior of salt intake. Hypothesis: The purpose of this study was to evaluate the reliability of an adapted-sensory analysis method for rapid determination of salt taste Detection Threshold (DT - the minimum concentration necessary to detect the stimulus) and Recognition Threshold (RT - the minimum concentration necessary to recognize the salty stimulus). Methods: The temporal stability of a rapid sensory analysis based on the 3-alternative forced-choice (3-AFC) method (ASTM E679) was tested with 30 adult volunteers. DT and RT for salt were determined using a 15 series of ascending concentrations of salt (from 1 to 290 mM; 1,5-fold steps). Intraclass correlation coefficient (ICC) was used to test the agreement between the results of the test-retest (1-week interval). For the analysis, the threshold values were log-transformed. Results: The average time of the trial per participant was 16.7 minutes. Standard deviation on log-transformed DT and RT values quite were variable among subjects. Means for both DT and RT were lower in the retest: 2,99 mM (test) vs. 2,41 mM (retest) for DT; and 19,04 mM (test) vs. 13,76 mM (retest) for RT. However, the test-retest results for both thresholds were reasonably in agreement, as confirmed by the ICCs observed: 0.599 (CI95%; 0,157 - 0,809) and 0.783 (CI95%; 0,545 - 0,897) for DT and RT, respectively. Conclusions: The sensory analysis method used in this study exhibited evidence of temporal stability, thus of a reliable measure. This observation and the fact of being fast and simple to perform for both experimenter and participant, reinforce its suitability for the determination of salt taste thresholds in studies involving large numbers of subjects. Linking between taste sensitivity to salt consumption and some clinical characteristics such as obesity and visceral fat, may help to understand the mutual influence of these variables, and suggest appropriate interventions to reduce salt intake among individuals at higher cardiovascular risk.

A new rapid detection threshold method for use with older adults: Reducing fatigue whilst maintaining accuracy

Taste and smell detection threshold measurements are frequently time consuming especially when the method involves reversing the concentrations presented to replicate and improve accuracy of results. These multiple replications are likely to cause sensory and cognitive fatigue which may be more pronounced in elderly populations. A new rapid detection threshold methodology was developed that quickly located the likely position of each individuals sensory detection threshold then refined this by providing multiple concentrations around this point to determine their threshold. This study evaluates the reliability and validity of this method. Findings indicate that this new rapid detection threshold methodology was appropriate to identify differences in sensory detection thresholds between different populations and has positive benefits in providing a shorter assessment of detection thresholds. The results indicated that this method is appropriate at determining individual as well as group detection thresholds.

Gustatory responsiveness to the 20 proteinogenic amino acids in the spider monkey (Ateles geoffroyi)

The gustatory responsiveness of four adult spider monkeys to the 20 proteinogenic amino acids was assessed in two-bottle preference tests of brief duration (1min). We found that Ateles geoffroyi responded with significant preferences for seven amino acids (glycine, l-proline, l-alanine, l-serine, l-glutamic acid, l-aspartic acid, and l-lysine) when presented at a concentration of 100mM and/or 200mM and tested against water. At the same concentrations, the animals significantly rejected five amino acids (l-tryptophan, l-tyrosine, l-valine, l-cysteine, and l-isoleucine) and were indifferent to the remaining tastants. Further, the results show that the spider monkeys discriminated concentrations as low as 0.2mM l-lysine, 2mM l-glutamic acid, 10mM l-proline, 20mM l-valine, 40mM glycine, l-serine, and l-aspartic acid, and 80mM l-alanine from the alternative stimulus, with individual animals even scoring lower threshold values. A comparison between the taste qualities of the proteinogenic amino acids as described by humans and the preferences and aversions observed in the spider monkeys suggests a fairly high degree of agreement in the taste quality perception of these tastants between the two species. A comparison between the taste preference thresholds obtained with the spider monkeys and taste detection thresholds reported in human subjects suggests that the taste sensitivity of A. geoffroyi for the amino acids tested here might match that of Homo sapiens. The results support the assumption that the taste responses of spider monkeys to proteinogenic amino acids might reflect an evolutionary adaptation to their frugivorous and thus protein-poor diet.

Changes in taste perception and eating behavior after bariatric surgery‐induced weight loss in women

ObjectiveRoux-en-Y gastric bypass (RYGB) surgery causes greater weight loss than laparoscopic adjustable gastric banding (LAGB). We tested the hypothesis that RYGB has weight loss-independent effects on taste perception which influence eating behavior and contribute to the greater weight loss.Design and MethodsSubjects were studied before and after ~20% weight loss induced by RYGB (n=17) or LAGB (n=10). We evaluated: taste sensitivity for sweet, salty and savory stimuli; sucrose and monosodium glutamate (MSG) preferences; sweetness palatability; eating behavior; and expression of taste-related genes in biopsies of fungiform papillae.ResultsWeight loss induced by both procedures caused the same decrease in: preferred sucrose concentration (−12±10%), perceived sweetness of sucrose (−7±5%), cravings for sweets and fast-foods (−22 ±5%), influence of emotions (−27±5%) and external food cues (−30±4%) on eating behavior, and expression of α-gustducin in fungiform papillae (all P-values <0.05). RYGB, but not LAGB, shifted sweetness palatability from pleasant to unpleasant when repetitively tasting sucrose (P=0.05). Neither procedure affected taste detection thresholds or MSG preferences.ConclusionsLAGB and RYGB cause similar alterations in eating behaviors, when weight loss is matched. These changes in eating behavior were not associated with changes in taste sensitivity, suggesting other, as yet unknown, mechanisms are involved.

Maximising umami taste in meat using natural ingredients: effects on chemistry, sensory perception and hedonic liking in young and old consumers

Umami taste in foods is elicited predominantly by the presence of glutamic acid and 5'-ribonucleotides, which act synergistically. This study aimed to use natural ingredients to maximise umami taste of a meat formulation and determine effects on liking of older consumers. Cooked meat products with added natural ingredients (yeast extract, mycoscent, shiitake extract, tomato puree, soy sauce and soybean paste) or monosodium glutamate (MSG) were prepared and compared with a control sample analytically (umami compounds), sensorially (sensory profile) and hedonically (liking by younger and older volunteers). Taste detection thresholds of sodium chloride and MSG of volunteers were collected. Four of the seven cooked meat products developed had a significantly higher content of umami-contributing compounds compared with the control. All products, except those containing MSG or tomato puree, were scored (by trained sensory panel) perceptually significantly higher in umami and/or salty taste compared with the control. Consumer tests showed a correlation of liking by the older cohort with perceived saltiness (ρ = 0.76). The addition of natural umami-containing ingredients during the cooking of meat can provide enhanced umami and salty taste characteristics. This can lead to increased liking by some consumers, particularly those with raised taste detection thresholds.

Reduced Taste Sensitivity in Congenital Blindness

Sight is undoubtedly not only important for food identification and selection but also for the modulation of gustatory sensitivity. We can, therefore, assume that taste sensitivity and eating habits are affected by visual deprivation from birth. We measured taste detection and identification thresholds of the 5 basic tastants in 13 congenitally blind and 13 sighted control subjects. Participants also answered several eating habits questionnaires, including the Food Neophobia Scale, the Food Variety Seeking Tendency Scale, the Intuitive Eating Scale, and the Body Awareness Questionnaire. Our behavioral results showed that compared with the normal sighted, blind subjects have increased thresholds for taste detection and taste identification. This finding is at odds with the superior performance of congenitally blind subjects in several tactile, auditory and olfactory tasks. Our psychometric data further indicate that blind subjects more strongly rely on internal hunger and satiety cues, instead of external contextual or emotional cues, to decide when and what to eat. We suggest that the lower taste sensitivity observed in congenitally blind individuals is due to various blindness-related obstacles when shopping for food, cooking and eating out, all of which contribute to underexpose the gustatory system to a larger variety of taste stimuli.

Evaluation of gustatory function in HIV‐infected subjects with and without HAART

Alteration in gustatory function among patients with human immunodeficiency virus (HIV) infection is sparsely studied and provides contradictory findings. The objectives of the study were to evaluate taste perversion in HIV-infected subjects and compare taste acuity between patients with and without Highly active antiretroviral therapy (HAART). Fifty HIV-infected subjects aged 25-55 years were selected and divided into two subgroups: patients with HAART and patients without HAART. Control group included 50 healthy, age-, sex-, gender-, and socioeconomic status-matched individuals. Taste complaints were recorded on a structured questionnaire, and formal taste testing was carried out with triadic forced choice whole-mouth, above-threshold taste test for four tastants - sweet, salt, sour, and bitter. Taste identification, detection threshold, and intensity of tastant were recorded. Twenty-four (48%) among study group complained of taste perversion when compared to none among the control group (P < 0.001). During taste testing, identification and intensity scores were lower, while detection threshold scores for four tastants were higher in study group than in control group (P < 0.05). Among those patients with taste complaints, 16 were with HAART, while eight were without HAART (P = 0.043). Formal taste testing revealed greater taste perversion for sour and bitter tastants among patients with HAART medication. The results document significant taste losses in HIV-infected subjects, and HAART contributes considerably to such taste perversion.

Effect of Acute Stress on Taste Perception: In Relation with Baseline Anxiety Level and Body Weight

We aimed to determine the effect of acute stress on taste perception and its modulation in relation to body weight and baseline anxiety in this study. The anxiety of the participants, randomly allocated to stress (n = 35) or control (n = 16) groups, was assessed by State Trait Anxiety Inventory. Stroop color-word interference and cold pressor tests were applied as stress protocol. Glucose and salt taste detection thresholds were evaluated before and after the stress protocol in the stress group and corresponding times in the control group. Stress protocol increased heart rate and blood pressure as an indicator of stress system activation. Following stress glucose and salt thresholds decreased in the stress group, unchanged in the control group. Prestress salt thresholds were positively and decrements in salt thresholds were negatively correlated with trait anxiety scores of participants. The state anxiety levels of stress group positively correlated with the decrease in glucose thresholds. Waist-to-hip ratio was negatively correlated with prestress salt thresholds of the subjects. Our results revealed that thresholds for sweet and salty tastes are modulated during stressful conditions. Our data also demonstrated a relationship between taste perception and baseline anxiety levels of healthy individuals, which may be important to understand the appetite alterations in individuals under stressful conditions.

Ageing and taste

Taste perception has been studied frequently in young and older adult groups. This paper systematically reviews these studies to determine the effect of ageing on taste perception and establish the reported extent of sensory decline. Five databases were searched from 1900 to April 2012. Articles relating to healthy ageing in human subjects were included, reviewed and rated (Downs and Black scoring system). Sixty-nine studies investigated the effect of ageing on taste perception; forty examined detection thresholds of which twenty-three provided sufficient data for meta-analysis, eighteen reported identification thresholds and twenty-five considered supra-threshold intensity perception. Researchers investigating detection thresholds considered between one and thirteen taste compounds per paper. Overall, the consensus was that taste detection thresholds increased with age (Hedges' g=0·91, P<0·001), across all taste modalities. Identification thresholds were reported to be higher for older adults in seventeen out of eighteen studies. Sixteen out of twenty-five studies reported perception of taste intensity at supra-threshold levels to be significantly lower for older adults. However, six out of nine studies concerning sucrose found perceived intensity of sweet taste not to diminish with age. The findings of this systematic review suggest taste perception declines during the healthy ageing process, although the extent of decline varies between studies. Overall, the studies reviewed had low Downs and Black scores (mean 16 (SD 2)) highlighting the need for more robust large scale and longitudinal studies monitoring the impact of ageing on the sensory system, and how this influences the perception of foods and beverages.

Taste Enhancement by Pulsatile Stimulation Is Receptor Based But Independent of Receptor Type

Effects of subjects’ taste sensitivity (expressed as taste detection threshold), tastant quality and taste transduction mechanism on pulsation-induced taste enhancement were tested. Taste intensities of pulsatile MSG and NaCl stimuli at pulsation periods below, at and above individual taste fusion periods (TFP in seconds) were compared to taste intensities of a continuous reference of the same net tastant concentration and quality. In line with results previously reported for sucrose, pulsation-induced taste enhancement peaked around TFP for both MSG and NaCl and did not require perception of tastant pulsation. TFP and pulsation effects were independent of the taste transduction mechanism (G-protein-coupled receptor for MSG versus ion-channel for NaCl). The absence of a relation between TFP and taste sensitivity suggests that temporal gustatory resolution and taste sensitivity are not necessarily influenced by the same factors. The results support earlier findings that early stages of taste transduction are involved in pulsation-induced taste enhancement. Pulsation-induced taste enhancement is determined by the pulsation rate (i.e. TFP) which is longer for MSG than NaCl. This is probably due to the tastant-specific interaction with the receptor rather than the taste transduction mechanism (G-protein-coupled receptor versus ion-channel) involved.

Sensation and perception of sucrose and fat stimuli predict the reinforcing value of food

Chronic overeating can lead to weight gain and obesity. Sensory system function may play a role in the types of foods people select and the amount of food people eat. Several studies have shown that the orosensory components of eating play a strong role in driving food intake and food selection. In addition, previous work has shown that motivation to get food, or the reinforcing value of food, is a predictor of energy intake. The purpose of this study was to test the hypothesis that higher detection thresholds and lower suprathreshold intensity ratings of sweet and fat stimuli are associated with greater reinforcing value of food. In addition, we sought to determine if the sensory ratings of the stimuli would differ depending on whether they were expectorated or swallowed. The reinforcing value of food was measured by having participants perform operant responses for food on progressive ratio schedules of reinforcement. Taste detection thresholds and suprathresholds for solutions containing varied concentrations of sucrose and fat were also measured in two different Experiments. In Experiment 1, we found that sucrose, but not fat, detection predicted the reinforcing value of food with the reinforcing value of food increasing as sucrose detection threshold increased (indicating poorer detection). In Experiment 2, we found that lower suprathreshold ratings of expectorated fat and sucrose predicted greater reinforcing value of food. In addition, higher detection thresholds for fat stimuli (indicating poorer detection) were associated with greater reinforcing value of food. When taken together, these studies suggest that there is a relationship between taste detection and perception and reinforcing value of food and that these relationships vary based on whether the stimulus is swallowed or expectorated.