Chlorine Water Taste Threshold and Acceptability among Indigenous and Non-Indigenous Populations in Rural Panama

Although gains in access to water services over the past two decades have been large, more than two billion people still lack access to safely managed drinking water. This study examines and compares free chlorine taste and acceptability thresholds of rural Indigenous Ngäbe and rural Latino Panamanians to study if taste aversion may be a limiting factor in chlorination of community systems in Panama using the three-alternative forced choice test methodology. This study is the first to establish a best-estimate taste threshold for a rural Indigenous group and the only study in Latin America to report best-estimate taste thresholds using those methods. Median taste thresholds were 0.87 mg/L Cl2 for Indigenous Ngäbe participants (n = 82) and 1.64 mg/L Cl2 for Latino participants (n = 64), higher than both the minimum concentration for biologically safe water (0.2 mg/L) and the recommended concentration range in Panama (0.3-0.8 mg/L). Median acceptability thresholds were established much higher than taste thresholds at 3.45 mg/L Cl2. The results show that the ability to accurately taste chlorine may not be the limiting factor for adoption of safe water initiatives in remote and Indigenous communities.

Human Gingival Fibroblasts as a Novel Cell Model Describing the Association between Bitter Taste Thresholds and Interleukin-6 Release

Human gingival fibroblast cells (HGF-1 cells) present an important cell model to investigate the gingiva's response to inflammatory stimuli such as lipopolysaccharides from Porphyromonas gingivalis (Pg-LPS). Recently, we demonstrated trans-resveratrol to repress the Pg-LPS evoked release of the pro-inflammatory cytokine interleukin-6 (IL-6) via involvement of bitter taste sensing receptor TAS2R50 in HGF-1 cells. Since HGF-1 cells express most of the known 25 TAS2Rs, we hypothesized an association between a compound's bitter taste threshold and its repressing effect on the Pg-LPS evoked IL-6 release by HGF-1 cells. To verify our hypothesis, 11 compounds were selected from the chemical bitter space and subjected to the HGF-1 cell assay, spanning a concentration range between 0.1 μM and 50 mM. In the first set of experiments, the specific role of TAS2R50 was excluded by results from structurally diverse TAS2R agonists and antagonists and by means of a molecular docking approach. In the second set of experiments, the HGF-1 cell response was used to establish a linear association between a compound's effective concentration to repress the Pg-LPS evoked IL-6 release by 25% and its bitter taste threshold concentration published in the literature. The Pearson correlation coefficient revealed for this linear association was R² = 0.60 (p < 0.01), exceeding respective data for the test compounds from a well-established native cell model, the HGT-1 cells, with R² = 0.153 (p = 0.263). In conclusion, we provide a predictive model for bitter tasting compounds with a potential to act as anti-inflammatory substances.

Detection of Bitterness in Vitamins Is Mediated by the Activation of Bitter Taste Receptors

Vitamins are known to generate bitterness, which may contribute to an off-taste or aftertaste for some nutritional supplements. This negative sensation can lead to a reduction in their consumption. Little is known about the bitter taste threshold and taste sensing system for the bitter taste detection of vitamins. To better understand the mechanisms involved in bitterness perception, we combined taste receptor functional assays and sensory analysis. In humans, bitter taste detection is mediated by 25 G-protein-coupled receptors belonging to the TAS2R family. First, we studied the bitterness of thirteen vitamins using a cellular-based functional taste receptor assay. We found four vitamins that can stimulate one or more TAS2Rs. For each positive molecule-receptor combination, we tested seven increasing concentrations to determine the half-maximal effective concentration (EC₅₀) and the cellular bitter taste threshold. Second, we measured the bitter taste detection threshold for four vitamins that exhibit a strong bitter taste using a combination of ascending series and sensory difference tests. A combination of sensory and biological data can provide useful results that explain the perception of vitamin bitterness and its real contribution to the off-taste of nutritional supplements.

The Number of Fungiform Papillae, Taste Sensitivity and Smell Functions of Children Aged 11–15

Differences in the ability to identify and perceive tastes and smells might influence food consumption and, ultimately, chronic nutrition-related conditions such as overweightness and obesity. This study aimed to investigate the associations between taste sensitivity and odour function, anthropometry, and quantity of fungiform papillae in children at age 11–15. Taste strips (4 base tastes), U-Sniff sticks (12 selected smells), and a filter paper strip impregnated with 6-n-propylthiouracil (PROP) were used. The photographic method was used to estimate the number of fungiform papillae (FP) on the tongue. The results showed that the quantity of FP was not related to anthropometry or gender. The taste test total scores were higher for girls, for whom the median score was 14 (12.0–15.0), than for boys, for whom the median score was 12 (9.0–13.0). Of the children, 13.9% had some difficulty in identifying odours. The Mann–Whitney U test showed that children who were most sensitive to bitter taste had more FP (p = 0.0001). The median score for this group (score = 4) was 34.0 (27.0–37.0). For those who had some problems with correctly assessing all bitter taste strips (score = 0–3), the median score was 24.0 (20.0–31.0). Higher numbers of FP were also observed in tasters, that is, people sensitive to PROP, than in nontasters. Only some measures of the taste function correlated with each other, but not very significantly. We concluded that there are multiple perceptual phases of taste, with no single measure able to entirely represent the sense of taste.

Does Each Menstrual Cycle Elicit a Distinct Effect on Olfactory and Gustatory Perception?

The obesity pandemic has brought forth a scientific interest in food intake and sensory perception interactions. Olfactory perception and gustatory perception are very complex and under the influence of many factors, including the menstrual cycle. This study aims to clarify conflicting findings on the influence of the menstrual cycle on olfactory and gustatory perception. Women were assessed during four consecutive phases of one complete cycle (mid-follicular, ovulatory, mid-luteal, and late luteal phases (N = 21)), in contrast to women measured across the same phases belonging to two menstrual cycles (N = 29). Additional control groups were men (N = 17), postmenopausal women (N = 14), oral contraceptive users (N = 10), and women with an anovulatory cycle (N = 8). Olfactory threshold, odor discrimination, and identification were tested using the "Sniffin Sticks" test kit. Suprathreshold intensity and hedonic ratings for sweet, salty, sour, and bitter solutions were assessed. One-way ANOVA and ANOVA for repeated measurements was applied in the analysis, along with linear and trigonometric data fitting and linear mixed models. Linear increases in olfactory discrimination, identification, and overall olfactory performance were observed only in women followed across a complete menstrual cycle. Compared to other groups, these women displayed a cyclic pattern characterized by a predilection for sweet solution; reduced distaste for salty and sour solutions; and increased intensity perception of salty, sour, and bitter solutions towards the end of the cycle. These results suggest that a distinct hormonal milieu of a complete menstrual cycle may be affecting both olfactory and gustatory perception.

Impaired Taste Perception in Lichen Planus Patients with Tongue Involvement

PURPOSE

To analyse the taste function in a pool of untreated patients with oral lichen planus (OLP) with tongue lesions (n = 35) and without tongue lesions (n = 36) and to compare it to healthy subjects (n = 36).

MATERIALS AND METHODS

Firstly, the subjective overall taste ability and impairment of the sensations of 'sweet', 'sour', 'salty' and 'bitter' were recorded in all three groups. Secondly, taste function was tested in all included subjects using the standardised 'Taste Strips' test.

RESULTS

Data showed a statistically statistically significant difference in overall taste perception between OLP patients with tongue lesions and control subjects (p = 0.027) for the tested taste function. The sensation of 'sour' showed the most pronounced difference (p = 0.08). The subjective taste perception and that of individual taste qualities did not differ statistically significantly between the three groups, and the correlation between subjective and objective taste perception was low. There was also a low correlation between taste scores and the presence of lesions on different areas of the tongue.

CONCLUSION

For patients with OLP experiencing a loss in appetite, a formal taste examination and subsequent counselling should be considered.

Taste Sensitivity of Elderly People Is Associated with Quality of Life and Inadequate Dietary Intake

Aging has been implicated in the alteration of taste acuity. Diet can affect taste sensitivity. We aimed to investigate the types of tastes altered in elderly Korean people and factors associated with taste alteration in relation to dietary intake and other factors. Elderly participants (≥65 years) and young adults were assessed to determine their recognition thresholds (RT) for sweet, salty, bitter, sour, and umami tastes. Elderly participants were further surveyed for dietary intake and non-nutritional factors. Five taste RTs were correlated with age, but only four taste RTs, except sweetness, differed between the elderly participants and young adults. Inadequate intake of iron, thiamin, folic acid, zinc, and phosphorus among the elderly participants was related to elevated taste RT levels, except for bitter taste. In both correlation and regression analyses, only salty and sour RTs were associated with energy, iron, thiamin, fiber, vitamin C, and riboflavin levels in the elderly participants. The elderly participants’ taste RTs exhibited strong associations with quality of life (QOL) but showed partial relationships with physical activity, number of medicine intakes, social gatherings, and education. Taste sensitivity may decrease with age, which is further influenced by insufficient dietary intake, especially iron and thiamin, and QOL.

Is sonic hedgehog expression in saliva related to taste sensitivity in adults?

Recent studies have demonstrated the critical role of the sonic hedgehog in the sensory perception of taste. Salivary sonic hedgehog stimulates taste bud stem cells, also acts as a taste bud growth factor, and contributes to the receptors' development and longevity in the taste buds. This study's objective was to investigate the possible relationship between taste sensitivity and sonic hedgehog expression in saliva in normal-weight and pre-obese/obese participants (totally 46 male (47.8%) and female (52.2%) aged 19-44 were recruited). Thresholds for the six tastes (sweet, salty, bitter, sour, umami and fat) were investigated using 3-Alternate Forced Choice Methodology. Saliva was collected with the draining method for sonic hedgehog expression analysis. The results indicated significantly higher thresholds for sweet, bitter and fat in pre-obese /obese adults than normal-weight adults (p<0.05). The sonic hedgehog expression was also lower in pre-obese /obese participants than normal-weight participants (p<0.05). Furthermore, sonic hedgehog expression was higher in hypersensitive participants than hyposensitive participants (p<0.05) only among normal-weight individuals, with no significant difference in sonic hedgehog expression level by taste sensitivity in pre-obese/obese individuals (p>0.05). Sonic hedgehog expression level was negatively correlated with body mass index, sweet, salty, bitter and fat taste threshold. The study results indicated that sonic hedgehog expression level acted on taste sensitivity in normal-weight participants, with greater expression in hypersensitive individuals than hyposensitive individuals.

Taste detection threshold of human (Homo sapiens) subjects and taste preference threshold of black-handed spider monkeys (Ateles geoffroyi) for the sugar substitute isomalt

The artificial sweetener isomalt is widely used due to its low caloric, non-diabetogenic and non-cariogenic properties. Although the sweetening potency of isomalt has been reported to be lower than that of sucrose, no data on the sensitivity of humans for this polyol are available. Using an up-down, two-alternative forced choice staircase procedure we therefore determined taste detection thresholds for isomalt in human subjects (n = 10; five females and five males) and compared them to taste preference thresholds, determined using a two-bottle preference test of short duration, in a highly frugivorous nonhuman primate, the spider monkey (n = 4; one female, three males). We found that both species detected concentrations of isomalt as low as 20 mM. Both humans and spider monkeys are less sensitive to isomalt than to sucrose, which is consistent with the notion of the former being a low-potency sweetener. The spider monkeys clearly preferred all suprathreshold concentrations tested over water, suggesting that, similar to humans, they perceive isomalt as having a purely sweet taste that is indistinguishable from that of sucrose. As isomalt, like most sweet-tasting polyols, may elicit gastric distress when consumed in large quantities, the present findings may contribute to the choice of appropriate amounts and concentrations of this sweetener when it is employed as a sugar substitute or food additive for human consumption. Similarly, the taste preference threshold values of spider monkeys for isomalt reported here may be useful for determining how much of it should be used when it is employed as a low-caloric sweetener for frugivorous primates kept on a vegetable-based diet, or when medication needs to be administered orally.

Changes of taste perception after stapes surgery: a prospective cohort study

PURPOSE

Taste perception is often affected after stapes surgery despite effort to preserve chorda tympani nerve. The aim was to examine changes of particular taste qualities and their recovery after operation of otosclerosis.

MATERIALS AND METHODS

Taste function was prospectively investigated with a questionnaire and a taste strip test (TST) preoperatively, 3-5 days and 1 year after stapes surgery with the preservation of CTN.

RESULTS

In the early postoperative examination, 34/42 patients had a lower TST score, 7/42 decrease of taste in the questionnaire. One year after surgery, 11/42 patients had a lower TST score, 1/42 patients decrease of taste in the questionnaire. The most pronounced decrease in the TST score was in sweet (- 1.76 points, p < 0.001), followed by bitter (- 1.71 points, p < 0.001), salty (- 1.64 points, p < 0.001) and sour taste (- 1.33 points, p < 0.001). The sour taste had a significant lower alteration compared to others. Men had significantly pronounced alteration in salty taste compared to women. The complete recovery was proved in bitter taste. Better recovery in bitter taste was observed in patients younger than 45 years of age.

CONCLUSIONS

Gustatory changes after stapes surgery are mostly transient with different impairment and recovery rate for particular taste qualities. A sour taste seems to be relatively resistant to damage. The best recovery rate is in a bitter taste, especially in younger patients.

Identification of inhibitors of pinellic acid generation in whole wheat bread

Bitterness is a common aversive flavor attribute of foods associated with low consumer acceptance. Untargeted LC-MS flavoromic profiling was utilized to identify endogenous compounds that influence the generation of the bitter compound 9,12,13-trihydroxy-trans-10-octadecenoic acid (pinellic acid) during bread making. A diverse sample set of wheat germplasm was chemically profiled. The corresponding pinellic acid concentrations after dough formation were modeled by orthogonal partial least squares (OPLS) with good fit (R²Y = 0.8) and predictive ability (Q² = 0.6). The most predictive feature (negatively correlated), postulated to interfere with the biosynthetic pathway, was identified as schaftoside, an apigenin di-C-glycoside. Recombination experiments involving the addition of schaftoside to flour prior to breadmaking resulted in a 26% decrease in pinellic acid formation and significantly lower perceived bitterness intensity in whole wheat bread. This work provides novel understanding of bitter generation pathways in wheat products and new strategies to improve flavor profiles and consumer acceptability.

Elevated Salt Taste Threshold Is Associated with Increased Risk of Coronary Heart Disease

High salt intake has been associated with coronary heart disease (CHD). The salt taste threshold could affect the salt intake, but its role in CHD is uncertain. We studied the association of salt taste threshold with CHD. In this study, the levels of salt detection threshold, recognition threshold, and taste preference were higher in CHD than in controls. The salt taste recognition threshold was significantly associated with CHD, and the significant association persisted after adjustment for traditional risk factors. Individuals with high level of salt taste recognition threshold were at a greater risk of CHD. Coincident occurrence of high level of salt taste recognition threshold, hypertension, and diabetes increased the risk of CHD. Thus, a high level of salt taste recognition threshold increases the risk of CHD, and the concurrence of high level of salt taste recognition threshold, hypertension, and diabetes further increases the risk of CHD.

Characterization of the Aroma of an Instant White Tea Dried by Freeze Drying

The aroma of an instant white tea (IWT) was extracted through simultaneous distillation–extraction (SDE) and analyzed by sensory evaluation, gas chromatography-mass spectrometry-olfactometry (GC-MS-O), aroma reconstruction, omission test and synergistic interaction analysis. Sensory evaluation showed the IWT was dominated with floral and sweet notes. The SDE extract had the aroma similar to the IWT. The main volatile components in the SDE extract were benzyl alcohol, linalool, hotrienol, geraniol, α-terpineol, coumarin, camphene, benzeneacetaldehyde, 2-hexanone, cis-jasmin lactone and phenylethyl alcohol. GC-MS-O and aroma reconstruction experiments showed 16 aroma-active compounds. Linalool, trans-β-damascenone and camphene were the major contributors to floral, sweet and green notes based on flavor dilution analysis and omission test. Linalool and trans-β-damascenone had synergistic effect to promote floral and sweet notes. Camphene and trans-β-damascenone had synergistic effect to reduce green and sweet notes. The study helps to understand the aroma of IWT and antagonism interactions among aroma-active volatiles.

Discrimination of Isointense Bitter Stimuli in a Beer Model System

Prior work suggests humans can differentiate between bitter stimuli in water. Here, we describe three experiments that test whether beer consumers can discriminate between different bitterants in beer. In Experiment 1 (n = 51), stimuli were intensity matched; Experiments 2 and 3 were a difference from control (DFC)/check-all-that-apply (CATA) test (n = 62), and an affective test (n = 81). All used a commercial non-alcoholic beer spiked with Isolone (a hop extract), quinine sulfate dihydrate, and sucrose octaacetate (SOA). In Experiment 1, participants rated intensities on general labeled magnitude scales (gLMS), which were analyzed via ANOVA. In Experiment 2, participants rated how different samples were from a reference of Isolone on a 7-point DFC scale, and endorsed 13 attributes in a CATA task. DFC data were analyzed via ANOVA with Dunnett's test to compare differences relative to a blind reference, and CATA data were analyzed via Cochran's Q test. In Experiment 3, liking was assessed on labeled affective magnitude scales, and samples were also ranked. Liking was analyzed via ANOVA and rankings were analyzed with a Cochran-Mantel-Haenszel test. Experiment 1 confirmed that samples were isointense. In Experiment 2, despite being isointense, both quinine (p = 0.04) and SOA (p = 0.03) were different from Isolone, but no significant effects were found for CATA descriptors (all p values > 0.16). In Experiment 3, neither liking (p = 0.16) or ranking (p = 0.49) differed. Collectively, these data confirm that individuals can discriminate perceptually distinct bitter stimuli in beer, as shown previously in water, but these differences cannot be described semantically, and they do not seem to influence hedonic assessments.

Taste test using an edible taste film kit: a randomised controlled trial

OBJECTIVES

We developed an edible taste film test that can be stored easily as a kit. This study was conducted to confirm the agreement between the results of the edible taste film kit test and the conventional taste solution test.

DESIGN

Prospective, randomised, controlled trial.

SETTING

Single tertiary hospital.

PARTICIPANTS

Sixty-two healthy volunteers with no self-described taste problems.

INTERVENTIONS

A randomisation scheme was used to determine the order of use of the edible taste film kit and the taste solution test for each subject. The taste solution test was performed using a cotton swab. In the taste film kit test, an edible taste film was placed on the tongue, and the subject detected the taste after the film was dissolved by saliva.

OUTCOME MEASURES

For each test, we measured the taste identification threshold, taste detection time and total test time.

RESULTS

We confirmed the consistency of the taste identification thresholds of the two tests, and the results were consistent with each other except for the bitter taste results, which used coffee in the edible taste film kit and quinine in the taste solution test. Although the detection time for each taste quality was faster for the taste solution test, the mean total time was significantly shorter for the taste film kit test than for the taste solution test (6.16±2.27 min vs 7.04±1.98 min, respectively; p=0.004).

CONCLUSIONS

The edible taste film kit along with the taste solution test will be useful for quantitative taste testing.

TRIAL REGISTRATION NUMBER

KCT0002865.

Taste responsiveness of Western chimpanzees (Pan troglodytes verus) to five food-associated saccharides

Using a two-bottle choice test of short duration, we determined taste preference thresholds for sucrose, fructose, glucose, lactose, and maltose in three Western chimpanzees (Pan troglodytes verus). Further, we assessed relative preferences for these five saccharides when presented at equimolar concentrations and determined taste preference difference thresholds for sucrose, that is, the smallest concentration difference at which the chimpanzees display a preference for one of the two options. We found that the chimpanzees significantly preferred concentrations as low as 20 mM sucrose, 40 mM fructose, and 80 mM glucose, lactose, and maltose over tap water. When given a choice between all binary combinations of these five saccharides presented at equimolar concentrations of 100, 200, and 400 mM, respectively, the animals displayed significant preferences for individual saccharides in the following order: sucrose > fructose > glucose = maltose = lactose. The taste difference threshold for sucrose, expressed as Weber ratio (ΔI/I), was 0.3 and 0.4, respectively, at reference concentrations of 100 and 200 mM. The taste sensitivity of the chimpanzees to the five saccharides falls into the same range found in other primate species. Remarkably, their taste preference thresholds are similar, and with two saccharides even identical, to human taste detection thresholds. The pattern of relative taste preferences displayed by the chimpanzees was similar to that found in platyrrhine primates and to the pattern of relative sweetness as reported by humans. Taken together, the results of the present study are in line with the notion that taste sensitivity for food-associated carbohydrates may correlate positively with phylogenetic relatedness. Further, they support the notion that relative preferences for food-associated carbohydrates, but not taste difference thresholds, may correlate with dietary specialization in primates.

Development of a Gustatory Function Test for Clinical Application in Korean Subjects

PURPOSE

To obtain validated clinical values suitable for developing a gustatory function test, including umami taste, in a Korean population.

MATERIALS AND METHODS

The investigation involved 297 participants with self-reported normal sense of taste and smell. Liquid solutions were used for the assessment of gustatory function. The test consisted of 30 taste solutions [six concentrations of five tastants (sweet, bitter, salty, sour, and umami)]. For evaluation of overall gustatory function, the number of detected or correctly recognized taste thresholds was combined to form a "taste score."

RESULTS

Mean values of each detection and recognition threshold for the five tastes in men were consistently lower than those of women. The 10th percentile of taste score for recognition was used as the cut-off value for distinguishing normogeusia from hypogeusia. In subgroup analysis, total taste score from recognition thresholds revealed a significant negative correlation with age, indicating lower scores for increasing age. Taste score for non-smokers was significantly higher than that of smokers, in terms of detection and recognition of taste sensitivities.

CONCLUSION

This gustatory function test was easy to perform, affordable, and time-saving, with the capacity to self-produce and obtain reliable data. Gustatory function was more sensitive in young people, women, and non-smokers.

Fat Taste Sensitivity Is Associated with Short-Term and Habitual Fat Intake

Evidence suggests individuals less sensitive to fat taste (high fat taste thresholds (FTT)) may be overweight or obese and consume greater amounts of dietary fat than more sensitive individuals. The aims of this study were to assess associations between FTT, anthropometric measurements, fat intake, and liking of fatty foods. FTT was assessed in 69 Australian females (mean age 41.3 (15.6) (SD) years and mean body mass index 26.3 (5.7) kg/m²) by a 3-alternate forced choice methodology and transformed to an ordinal scale (FT rank). Food liking was assessed by hedonic ratings of high-fat and reduced-fat foods, and a 24-h food recall and food frequency questionnaire was completed. Linear mixed regression models were fitted. FT rank was associated with dietary % energy from fat ( β ^ = 0.110 [95% CI: 0.003, 0.216]), % energy from carbohydrate ( β ^ = -0.112 [-0.188, -0.035]), and frequency of consumption of foods per day from food groups: high-fat dairy ( β ^ = 1.091 [0.106, 2.242]), meat & meat alternatives ( β ^ = 0.669 [0.168, 1.170]), and grain & cereals ( β ^ = 0.771 [0.212, 1.329]) (adjusted for energy and age). There were no associations between FT rank and anthropometric measurements or hedonic ratings. Therefore, fat taste sensitivity appears to be associated with short-term fat intake, but not body size in this group of females.

Taste assessment in normal weight and overweight individuals with co-occurring Binge Eating Disorder

BACKGROUND

Taste perception influences food choice, and may contribute to both weight status and disordered eating. Relatively little work has attempted to disentangle contributions of weight status and Binge Eating Disorder (BED) to human taste perception. We predicted weight status and BED would interact, showing difference in taste perception from non-eating disorder matched groups.

METHODS

The four study groups included: normal weight BED (NW BED), normal weight healthy controls (NW HC), overweight BED (OW BED), and overweight healthy controls (OW HC) (N = 60). Groups were matched for age (±5 years), ethnicity, and weight status. Participants were assessed using the Structured Clinical Interview for DSM-IV Axis I Disorders, the Eating Disorder Examination Version 16.0, and the NIH Toolbox Gustatory Assessment with additional taste solutions and taste stimulus delivered with edible taste strips.

RESULTS

Interactions were found between weight status and diagnosis on measures of regional taste intensity for quinine hydrochloride (CI 95% [44.61, 56.31], p = 0.018), sucrose (CI 95% [46.79, 56.45], p = 0.003), and 6-n-propylthiouracil (CI 95% [25.557, 39.269], p = 0.015). OW BED participants perceived these taste stimuli significantly less intensely than OW HC and NW BED. Whole mouth taste intensity tests at suprathreshold amounts did not reveal group differences. All four groups reported similar hedonic response to taste stimuli. Edible taste strips had medium to large significant correlations with NIH Gustatory Assessment taste stimuli.

CONCLUSIONS

There were significant differences in the taste perception of OW BED relative to the other three groups. These findings may provide partial explanation as to why previous studies correlating taste and weight status have mixed results. Replication in larger samples assessed longitudinally is needed to extend this work.

Comparisons of Fatty Acid Taste Detection Thresholds in People Who Are Lean vs. Overweight or Obese: A Systematic Review and Meta-Analysis

Given the increasing evidence that supports the ability of humans to taste non-esterified fatty acids (NEFA), recent studies have sought to determine if relationships exist between oral sensitivity to NEFA (measured as thresholds), food intake and obesity. Published findings suggest there is either no association or an inverse association. A systematic review and meta-analysis was conducted to determine if differences in fatty acid taste sensitivity or intensity ratings exist between individuals who are lean or obese. A total of 7 studies that reported measurement of taste sensations to non-esterified fatty acids by psychophysical methods (e.g.,studies using model systems rather than foods, detection thresholds as measured by a 3-alternative forced choice ascending methodology were included in the meta-analysis. Two other studies that measured intensity ratings to graded suprathreshold NEFA concentrations were evaluated qualitatively. No significant differences in fatty acid taste thresholds or intensity were observed. Thus, differences in fatty acid taste sensitivity do not appear to precede or result from obesity.

High maltose sensitivity of sweet taste receptors in the Japanese macaque (Macaca fuscata)

Taste sensitivity differs among animal species depending on feeding habitat. To humans, sucrose is one of the sweetest natural sugars, and this trait is expected to be similar in other primates. However, previous behavioral tests have shown that some primate species have equal preferences for maltose and sucrose. Because sweet tastes are recognized when compounds bind to the sweet taste receptor Tas1R2/Tas1R3, we evaluated the responses of human and Japanese macaque Tas1R2/Tas1R3 to various natural sugars using a heterologous expression system. Human Tas1R2/Tas1R3 showed high sensitivity to sucrose, as expected; however, Japanese macaque Tas1R2/Tas1R3 showed equally high sensitivity to maltose and sucrose. Furthermore, Japanese macaques showed equally high sensitivity to sucrose and maltose in a two-bottle behavioral experiment. These results indicate that Japanese macaques have high sensitivity to maltose, and this sensitivity is directly related to Tas1R2/Tas1R3 function. This is the first molecular biological evidence that for some primate species, sucrose is not the most preferable natural sugar, as it is for humans.

Cross-cultural validation of a taste test with paper strips

Taste dysfunctions influence food choices, interpersonal communication and danger/health. A gustometry protocol is the mainstream for clinical taste disorders diagnosis and suggests possible therapeutics. No clinical gustometry protocol has been adapted and validated to the Portuguese population so far. We aim to validate a gustometry protocol based on strips made from filter paper impregnated with different taste solutions. Four concentrations each for sweet, sour, salty and bitter were administered to 75 subjects. Hypogeusia threshold is of 4.8 in this population. Repeated measures indicated a good reliability and validity for the taste strips (ρ 75 = 0.68, p < 0.001). Although Mediterranean food implies a heathy eating pattern, taste threshold scores may be lower because of its habituation to natural food flavoring. The taste strip gustometry protocol can be applied to the clinical practice in Portugal. It is quick, effective and cheap. The diagnostic utility of this method is indisputable, as well as the advantages we can obtain with its application, for early diagnosis and distinction between disorders of taste and smell.

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/m(2) (normal-weight group) and 18 with BMI >25 kg/m(2) (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).

Nonnutritive sweeteners are not supernormal stimuli

BACKGROUND

It is often claimed that nonnutritive sweeteners (NNS) are 'sweeter than sugar', with the implicit implication that high-potency sweeteners are supernormal stimuli that encourage exaggerated responses. This study aimed to investigate the perceived sweetness intensity of a variety of nutritive sweeteners (sucrose, maple syrup and agave nectar) and NNS (acesulfame-K (AceK), rebaudioside A (RebA), aspartame and sucralose) in a large cohort of untrained participants using contemporary psychophysical methods.

METHODS

Participants (n=401 total) rated the intensity of sweet, bitter and metallic sensations for nutritive sweeteners and NNS in water using the general labeled magnitude scale.

RESULTS

Sigmoidal dose-response functions were observed for all stimuli except AceK. That is, sucrose follows a sigmoidal function if the data are not artifactually linearized via prior training. More critically, there is no evidence that NNS have a maximal sweetness (intensity) greater than sucrose; indeed, the maximal sweetness for AceK, RebA and sucralose were significantly lower than that for concentrated sucrose. For these sweeteners, mixture suppression due to endogenous dose-dependent bitter or metallic sensations appears to limit maximal perceived sweetness.

CONCLUSIONS

In terms of perceived sweetness, NNS cannot be considered supernormal stimuli. These data do not support the view that NNS hijack or overstimulate sweet receptors to produce elevated sweet sensations.

Salt taste threshold and its relation to blood pressure in normotensive offspring of hypertensive parents amongst indian adolescents

To study Salt Taste Threshold (STT) and its relation to Blood pressure (BP) in normotensive adolescents, age and BMI matched 60 subjects of 18-20 years were segregated on basis of family history of hypertension, documented risk factor for development of hypertension. Student's unpaired t-test showed that STT and BP values were significantly higher in Hypertensive offspring group than Control. Pearson Chi Square test with 60 mM Nacl as cut-off point showed highly significant association of STT in hypertensive offspring group. A significant positive correlation was found between STT and BP by Pearson correlation analysis. Family history of hypertension is strongly linked to reduced salt taste sensitivity. This reinforces rationale that both conditions may be genetically linked though causal relation cannot be established. STT can be used as significant marker to screen 'salt sensible' subjects that eventually will develop hypertension and can be advised healthy habits early or prophylactically treated.

The role of sweet taste in satiation and satiety

Increased energy consumption, especially increased consumption of sweet energy-dense food, is thought to be one of the main contributors to the escalating rates in overweight individuals and obesity globally. The individual’s ability to detect or sense sweetness in the oral cavity is thought to be one of many factors influencing food acceptance, and therefore, taste may play an essential role in modulating food acceptance and/or energy intake. Emerging evidence now suggests that the sweet taste signaling mechanisms identified in the oral cavity also operate in the gastrointestinal system and may influence the development of satiety. Understanding the individual differences in detecting sweetness in both the oral and gastrointestinal system towards both caloric sugar and high intensity sweetener and the functional role of the sweet taste system may be important in understanding the reasons for excess energy intake. This review will summarize evidence of possible associations between the sweet taste mechanisms within the oral cavity, gastrointestinal tract and the brain systems towards both caloric sugar and high intensity sweetener and sweet taste function, which may influence satiation, satiety and, perhaps, predisposition to being overweight and obesity.

Not salt taste perception but self-reported salt eating habit predicts actual salt intake

Excessive dietary salt intake is related to cardiovascular morbidity and mortality. Although dietary salt restriction is essential, it is difficult to achieve because of salt palatability. However, the association between salt perception or salt eating habit and actual salt intake remains uncertain. In this study, we recruited 74 healthy young individuals. We investigated their salt-eating habits by questionnaire and salt taste threshold through a rating scale that used serial dilution of a sodium chloride solution. Predicted 24-hr urinary salt excretions using Kawasaki's and Tanaka's equations estimated dietary salt intake. Participants' mean age was 35 yr, and 59.5% were male. Salt sense threshold did not show any relationship with actual salt intake and a salt-eating habit. However, those eating "salty" foods showed higher blood pressure (P for trend=0.048) and higher body mass index (BMI; P for trend=0.043). Moreover, a salty eating habit was a significant predictor for actual salt intake (regression coefficient [β] for Kawasaki's equation 1.35, 95% confidence interval [CI] 10-2.69, P=0.048; β for Tanaka's equation 0.66, 95% CI 0.01-1.31, P=0.047). In conclusion, a self-reported salt-eating habit, not salt taste threshold predicts actual salt intake.

Pungent Qualities of Sanshool-Related Compounds Evaluated by a Sensory Test and Activation of Rat TRPV1

The detection threshold and taste characteristics of sanshools were examined by sensory evaluation, after isolating four sanshools (alpha-, beta-, gamma-, and delta-), and two hydroxy sanshools (alpha- and beta-) from the pericarp of Japanese pepper. The Scoville unit (SU) values of the four sanshools were in the range of 80,000-110,000, while those of hydroxy sanshools were 3-5 fold lower than corresponding sanshools. The pungent qualities of each sanshool were different. Burning and tingling were predominantly perceived and lasted for the longest time with alpha-sanshool. Burning and fresh for gamma-sanshool, and tingling and numbing for hydroxy alpha-sanshool were perceived. Tests on the activation of rat TRPV1 were also performed. All of them were weak agonists. Among them, gamma-sanshool was the most potent agonist, although its EC50 value of 5.3 microM was 230 fold higher than that of capsaicin. These results indicate that it would be difficult to explain the pungent quality of each sanshool simply in terms of TRPV1 activation.

Regeneration of the nerves in the aerial cavity with an artificial nerve conduit --reconstruction of chorda tympani nerve gaps-

OBJECTIVES/HYPOTHESIS

Due to its anatomical features, the chorda tympani nerve (CTN) is sometimes sacrificed during middle ear surgery, resulting in taste dysfunction. We examined the effect of placing an artificial nerve conduit, a polyglycolic acid (PGA)-collagen tube, across the gap in the section of the resected chorda tympani nerve (CTN) running through the tympanic cavity.

METHODS

The CTN was reconstructed with a PGA-collagen tube in three patients with taste disturbance who underwent CTN resection. To evaluate the effect of the reconstruction procedure on the patients' gustatory function, we measured the patients' electrogustometry (EGM) thresholds. The patients were followed-up for at least two years.

RESULTS

Gustatory function was completely restored in all of the patients after the reconstruction. The patients' EGM thresholds exhibited early improvements within one to two weeks and had returned to their normal ranges within three months. They subsequently remained stable throughout the two-year follow-up period. In a patient who underwent a second surgical procedure, it was found that the PGA-collagen tube used in the first surgical procedure had been absorbed and replaced by new CTN fibers with blood vessels on their surfaces.

CONCLUSION

These results suggest that reconstruction of the CTN with an artificial nerve conduit, a PGA-collagen tube, allows functional and morphological regeneration of the nerve and facilitates the recovery of taste function. PGA-collagen tubes might be useful for repairing CTNs that are resected during middle ear surgery. Further research is required to confirm these preliminary results although this is the first report to describe the successful regeneration of a nerve running through an aerial space.

Electrogustometry thresholds, tongue tip vascularization, and density and morphology of the fungiform papillae in diabetes

OBJECTIVES

The aim of this study was to investigate, in parallel, changes in electrogustometric (EGM) thresholds, the morphology and density of the fungiform papillae (fPap), and the shape and density of the vessels at the tip of the human tongue in patients with diabetes mellitus (DM).

METHODOLOGY

In 36 patients (19 females, 17 males; 12 subjects with type 1 DM and 24 subjects with type 2 DM), we recorded bilateral EGM-thresholds at the areas innervated by the chorda tympani, the glossopharyngeal nerves, and the greater petrosal nerves. We examined the morphology and density of the fPap and blood vessel density and morphology at the tip of the tongue with contact endoscopy (CE). A group of 36 healthy, age-matched, non-smoking individuals served as controls.

RESULTS

The fPap density measured by CE was significantly (p < 0.05) reduced in DM compared to control groups. EGM-thresholds were significantly higher in the DM group than in the control group (p < 0.05). Gender did not have a significant impact on CE and EGM findings within the DM group. Body mass index did not significantly affect EGM-thresholds or the morphology and vascularization of fPap.

CONCLUSION

These results suggested that DM significantly reduced gustatory function, based on EGM, and impaired the gustatory anatomical structures, based on CE. Both EGM and CE may be useful in clinical settings to monitor taste disorders in patients with DM.

Marked increase in PROP taste responsiveness following oral supplementation with selected salivary proteins or their related free amino acids

The genetic predisposition to taste 6-n-propylthiouracil (PROP) varies among individuals and is associated with salivary levels of Ps-1 and II-2 peptides, belonging to the basic proline-rich protein family (bPRP). We evaluated the role of these proteins and free amino acids that selectively interact with the PROP molecule, in modulating bitter taste responsiveness. Subjects were classified by their PROP taster status based on ratings of perceived taste intensity for PROP and NaCl solutions. Quantitative and qualitative determinations of Ps-1 and II-2 proteins in unstimulated saliva were performed by HPLC-ESI-MS analysis. Subjects rated PROP bitterness after supplementation with Ps-1 and II-2, and two amino acids (L-Arg and L-Lys) whose interaction with PROP was demonstrated by (1)H-NMR spectroscopy. ANOVA showed that salivary levels of II-2 and Ps-1 proteins were higher in unstimulated saliva of PROP super-tasters and medium tasters than in non-tasters. Supplementation of Ps-1 protein in individuals lacking it in saliva enhanced their PROP bitter taste responsiveness, and this effect was specific to the non-taster group.(1)H-NMR results showed that the interaction between PROP and L-Arg is stronger than that involving L-Lys, and taste experiments confirmed that oral supplementation with these two amino acids increased PROP bitterness intensity, more for L-Arg than for L-Lys. These data suggest that Ps-1 protein facilitates PROP bitter taste perception and identifies a role for free L-Arg and L-Lys in PROP tasting.

Cluster analysis application identifies muscle characteristics of importance for beef tenderness

BACKGROUND

An important controversy in the relationship between beef tenderness and muscle characteristics including biochemical traits exists among meat researchers. The aim of this study is to explain variability in meat tenderness using muscle characteristics and biochemical traits available in the Integrated and Functional Biology of Beef (BIF-Beef) database. The BIF-Beef data warehouse contains characteristic measurements from animal, muscle, carcass, and meat quality derived from numerous experiments. We created three classes for tenderness (high, medium, and low) based on trained taste panel tenderness scores of all meat samples consumed (4,366 observations from 40 different experiments). For each tenderness class, the corresponding means for the mechanical characteristics, muscle fibre type, collagen content, and biochemical traits which may influence tenderness of the muscles were calculated.

RESULTS

Our results indicated that lower shear force values were associated with more tender meat. In addition, muscles in the highest tenderness cluster had the lowest total and insoluble collagen contents, the highest mitochondrial enzyme activity (isocitrate dehydrogenase), the highest proportion of slow oxidative muscle fibres, the lowest proportion of fast-glycolytic muscle fibres, and the lowest average muscle fibre cross-sectional area. Results were confirmed by correlation analyses, and differences between muscle types in terms of biochemical characteristics and tenderness score were evidenced by Principal Component Analysis (PCA). When the cluster analysis was repeated using only muscle samples from m. Longissimus thoracis (LT), the results were similar; only contrasting previous results by maintaining a relatively constant fibre-type composition between all three tenderness classes.

CONCLUSION

Our results show that increased meat tenderness is related to lower shear forces, lower insoluble collagen and total collagen content, lower cross-sectional area of fibres, and an overall fibre type composition displaying more oxidative fibres than glycolytic fibres.

[Examination of taste threshold and serum zinc level change after chemotherapy]

For cancer patients undergoing chemotherapy, there is an onset of a variety of adverse events related to treatment. Among the adverse events at the moment is taste disorder, for which there is no established effective supportive care. We report the measurement and study their relationship across the changes in serum zinc and changes in the taste of patients undergoing chemotherapy. For cancer patients undergoing chemotherapy, taste threshold and serum zinc levels were measured on the day before administration of the therapeutic anti-cancer agent, and after administration of anticancer drugs on day 4 and day 7. Of taste thresholds in the test results, the threshold was salty on day 4 and day 7 after administration of anticancer agents, and a significant difference was found on day 7 after treatment with anticancer drugs on a day prior to administration of anticancer agents on day 1 (p<0. 001, p=0. 007), respectively. The serum zinc level was measured. There was no significant difference on day 7 after administration of anticancer agents and anti-cancer agent before administration on day 1 and day 7 after administration of anticancer drugs on day 4(p<0. 001, p<0. 05), respectively. A negative correlation was shown between the "salt of the fourth day threshold" and "serum zinc levels" (r=-0. 418, p<v0. 05). From the results of this study, salty and low serum zinc values tended to be blunted. The higher the serum zinc level was, the more sensitivity there was to salty taste.

Effects of selective adaptation on coding sugar and salt tastes in mixtures

Little is known about coding of taste mixtures in complex dynamic stimulus environments. A protocol developed for odor stimuli was used to test whether rapid selective adaptation extracted sugar and salt component tastes from mixtures as it did component odors. Seventeen human subjects identified taste components of "salt + sugar" mixtures. In 4 sessions, 16 adapt-test stimulus pairs were presented as atomized, 150-μL "taste puffs" to the tongue tip to simulate odor sniffs. Stimuli were NaCl, sucrose, "NaCl + sucrose," and water. The sugar was 98% identified but the suppressed salt 65% identified in unadapted mixtures of 2 concentrations of NaCl, 0.1 or 0.05 M, and sucrose at 3 times those concentrations, 0.3 or 0.15 M. Rapid selective adaptation decreased identification of sugar and salt preadapted ambient components to 35%, well below the 74% self-adapted level, despite variation in stimulus concentration and adapting time (<5 or >10 s). The 96% identification of sugar and salt extra mixture components was as certain as identification of single compounds. The results revealed that salt-sugar mixture suppression, dependent on relative mixture-component concentration, was mutual. Furthermore, like odors, stronger and recent tastes are emphasized in dynamic experimental conditions replicating natural situations.

Physiological taste threshold in type 1 diabetes mellitus

The sense of taste is one of the important oral chemical senses that play a critical role in human life. The taste threshold increases by number of factors such as age, local and systemic disease like diabetes, consumption of alcohol, smoking. The aim of the present study was to assess the relationship between taste threshold in type 1 diabetics and non diabetics for four basic taste modalities (i.e. sweet, salt, sour and bitter). We studied 70 cases of type 1 diabetic and 70 non diabetics. The taste threshold was evaluated using 7 different serially half diluted concentrations of glucose (2.00 M-0.031 M), Nacl (1.00 M-0.0156 M), citric acid (0.05 M-0.0007 M) and quinine sulphate (0.001 M-0.000015 M). A significant increase in taste threshold for sweet (P<0.0001), salt, sour and bitter (P<0.001) in type 1 diabetic was observed. We concluded that taste sensation was reduced in type 1 diabetics.

Evaluation of taste acuity by the filter-paper disc in Japanese young women: the relationship with micronutrients status

The aim of the present study is to investigate the taste acuity in Japanese young women in relation to their micronutrient status. Thirty-eight healthy young women (mean age; 21.3, range; 19-27 years) were enrolled. Gustatory thresholds were estimated for four basic tastes: sweet (sucrose), salty (sodium chloride), sour (tartaric acid), and bitter (quinine hydrochloride) by a filter-paper disk method. Various concentrations at each taste were serially scored from disc number 1 (lowest) to number 5 (highest). The lowest concentration at which the quality of the taste was correctly identified was defined as the recognition threshold. The mean of three measurements for each test on three different days was calculated. We divided our participants into normal taste and hypogeusia groups based on the mean threshold disc numbers, <=3.5 and >3.5, respectively, according to previous literature using the same method. We also measured serum concentrations and dietary intakes of micronutrients including zinc, iron, copper, and selenium. The numbers of participants belonging to the hypogeusia group were 24 (63.2%) for sweet, 19 (50.0%) for sour, 17 (44.7%) for bitter, and 16 (42.1%) for salty taste. Although the hypogeusia group exhibited significantly lower serum iron concentrations, except for the salty taste, the other three micronutrients concentrations did not show any association with the four taste acuities. Dietary micronutrient intake did not show any association with the four taste acuities. This study indicates that in addition to zinc status, iron status should be considered in the study of taste acuity.

[Universal electrogustometer EG-2]

Electrogustometry is a method for taste diagnosis and measurement. The EG-2 project is being developed in cooperation between Warsaw University of Technology and Military institute of Medicine in Warsaw. The device is an evolution of the recent universal electrogustometer EG-1 prototype. Due to considerations and experiences acquired during prototype usage, many enhancements have been incorporated into device. The aim was to create an easy-to-use, portable, battery powered device, enabled for fast measurements. Developed electrogustometer is using innovative, low-power microprocessor system, which control whole device. User interface is based on 5.7" graphical LCD (Liquid Crystal Display) and touchscreen. It can be directly operated by finger or with optional stylus. Dedicated GUI (Graphical User Interface) offers simple, predefined measurements and advance settings of signal parameters. It is also possible to store measurements results and patients data in an internal memory. User interface is multilanguage. Signals for patients examinations, supplied with bipolar electrode, are generated by an on-board circuit using DDS (Direct-Digital Synthesis) and DAC (Digital-to-Analog Converter). Electrogustometer is able to generate DC, sinus, triangle or rectangle signals with current amplitude from 0 to 500 pA and frequency form 0 to 500 Hz. Device is designed for manual and automeasurement modes. By using USB (Universal Serial Bus) port it is possible to retrieve data stored in internal memory and charging of built-in Li-lon battery as a source of power.

Salt-sensitivity in normotensive and hypertensive Nigerians

BACKGROUND

Salt-sensitivity increases the risk for the development of high blood pressure in susceptible persons and also increases the risk for cardiovascular events and mortality.

OBJECTIVE

The study is to determine the pattern of salt-sensitivity among normotensive and hypertensive Nigerians.

METHODS

Twenty-eight (28) hypertensive subjects (HT) and twenty-five (25) age-matched normotensive controls (NT) were given 200 mmol/day salt as sodium chloride for 5 days after control parameters had been determined. Subjects were regarded as salt-sensitive when change in mean arterial blood pressure (cMABP) between baseline levels and that after salt loading was > or = 5 mmHg.

RESULTS

Systolic blood pressure and mean arterial blood pressure but not diastolic blood pressure rose significantly (p < 0.05 and p < 0.001 respectively) in NT subjects while all the parameters showed significant increases in hypertensive subjects (SBP p < 0.01; DBP p < 0.001; MABP p < 0.0001). More hypertensive subjects (60.7%) were salt-sensitive compared with normotensive (52.0%) subjects (p < 0.05).

CONCLUSION

This study has demonstrated pressor responses to acute salt-loading in normotensive and hypertensive Nigerians and salt-sensitivity was higher in hypertensive subjects.

[Improvement of patient adherence by mixing oral itraconazole solution with a beverage (orange juice)]

There have been some reports on the efficacy and tolerability of an oral itraconazole (ITCZ) solution as prophylaxis for fungal infection in patients with hematological malignancies. However, there are some cases where the bitter taste of oral ITCZ solution leads to an interruption of administration because the patient refuses to take this medicine. Therefore, we prospectively investigated the pharmacokinetics and promotion of treatment adherence in patients taking oral ITCZ solution mixed with a beverage. Compared with the responses of patients taking oral ITCZ solution with water, the taste of the agent was improved significantly when mixed with orange juice, although the plasma concentration of the agent did not differ between the two groups. Using this method, we can expect an improvement in treatment adherence and this method can easily be applied in clinical practice. This method is highly useful and should become common knowledge.

Tap water consumers differ from non-consumers in chlorine flavor acceptability but not sensitivity

Unpleasant taste and especially chlorine flavor is one of the most common reasons advocated for choosing tap water alternatives as drinking water. As a consequence, the putative link between sensitivity to chlorine flavor and tap water consumption is an issue in drinking water habits studies. In the present study, we set out to examine such a link following a strategy in which we measured chlorine flavor perception at threshold and supra-threshold level for two groups of participants selected on their drinking water consumption habits. The first group included exclusive tap water consumers and the second group included exclusive bottled water consumers. In a first experiment, we used the constant stimuli procedure to evaluate the chlorine flavor detection threshold of a group of 20 tap water consumers and a group of 20 non-consumers. In a second experiment, a group of 18 tap water consumers and a group of 17 non-consumers evaluated supra-threshold flavor intensity, liking and acceptability for eight chlorinated solutions (0-10mg/L Cl(2)). The results revealed no significant difference in chlorine flavor detection threshold and supra-threshold sensitivity between tap water consumers and non-consumers. Nevertheless, tap water consumers showed a higher liking score for chlorinated solutions and were found to be more inclined to accept these solutions as drinking water. Taken together these findings suggested that consumers may disparage chlorine flavor in drinking water on the basis of their tap water cognitive representation.

Salt taste sensitivity, physical activity and gastric cancer

BACKGROUND

Gastric cancer is a major health issue in China. Risk factors are mainly related to nutrition and environment, with a particular role for high salt intake. The salt taste sensitivity threshold (STST) can influence salt consumption, and is therefore assumed to have association with gastric cancer. It was therefore assessed, together with other lifestyle factors, in the present study in China.

METHODS

A 1:2 matched hospital based case-control study, including 300 cases with a new histological confirmed diagnosis of gastric cancer and 600 controls that were cancer and gastric disease free, was conducted. A self-designed questionnaire was employed to collect information on dietary and lifestyle habit, including physical activity, and a salt taste sensitivity test was used to measure the STST for all subjects. Conditional logistic regression was used to calculated odds ratios (ORs) and 95% confidence intervals (95% CI).

RESULTS

An increased risk of gastric cancer was found related to smoking, alcohol drinking, family history of cancer and consumption of salted food. Walking and sports activity (adjusted OR=0.69(0.51-0.99) for ≥4 times/week) exerted protective effects. A significant positive association between increased STST and gastric cancer was evident, with an adjusted OR of 2.05 (1.68-2.5). When we used STST≥5 as a cut-off, the affected subjects were at 5.71 times greater risk of gastric cancer than those with STST　below 5. STST showed a moderate correlation with physical activity (Correlation coefficient =0.22). The cut point of STST≥5 had a best sensitivity and specificity for predicting gastric cancer risk (sensitivity for 73.7%, specificity of 57%).

CONCLUSION

Salt and salted food intake is associated with gastric cancer, while physical activity is protective. A high STST is strongly linked to gastric cancer risk.

Sensitivity to bitter and sweet taste perception in schoolchildren and their relation to dental caries

PURPOSE

The objective of the present study was to evaluate whether sensitivity to bitter taste and perception of sweet taste have an influence on dental caries in urban and rural areas.

MATERIALS AND METHODS

The caries experience in 181 children, aged 12 years, from rural and urban areas of southern Brazil, was assessed according to World Health Organization guidelines. Sensitivity to the bitterness of phenylthiocarbamide was determined using the Harris–Kalmus procedure, and the sweet taste thresholds of sucrose were measured by Nilsson and Holm's method.

RESULTS

The caries index (DMFT > 0) was 3.73 (SD = 2.26) in the rural area and 3.51 (SD = 2.14) in the urban area. The sensitivity to bitter taste and sweet taste perception showed significant association with the gender of schoolchildren (P = 0.04). Girls were predominant in the high sweet perception taster group (62.3%) and the bitter taster group (59.4%). No significant difference in sweet perception status could be observed between the groups of low and high caries severity. The genetic ability to taste bitterness significantly influenced the levels of caries only in children from the urban area (P = 0.005). Bitter non-tasters presented higher severity of caries. A positive correlation was observed between sensitivity to bitter taste and sweet taste perception among children in the rural (r = 0.42, P = 0.002) and urban areas (r = 0.36, P = 0.001).

CONCLUSIONS

These findings suggest that the bitter non-tasters are more susceptible to dental caries than the tasters in the urban area.

[Determination of gustatory sensitivity thresholds and functional mobility of receptor elements of oral cavity in patients with diabetes mellitus]

Condition of the gustatory perception in diabetes mellitus patients with compensated (51,9%), sub- (39,0%) and decompensated (9,1%) forms of glycolitic disorders was studied. Results allow to note that in the group of patients with decompensated form of the glucose homeostasis disorders reduction of the under investigation factor was more expressing (64,7+/-3,5%), than in the group with compensated (73,6+/-1,9%) and subcompensated (68,6+/-2,2%) forms of diabetes mellitus.

[Universal electrogustometer EG-1]

Electrogustometry has been used as a clinical tool for diagnosis and assessment of a variety of conditions. Since the lack of versatile electrogustometer for research and diagnosis, the new electrogustometer EG-1 was developed in 2006. It was done in cooperation between Warsaw University of Technology and Military Institute of Medicine in Warsaw. EG-1 allows quantitative estimation of taste perception threshold using both static and impulse electrogustometry with bipolar electrode. It is a fully autonomous, battery powered and portable instrument. Because of small size and weight, it can be easily placed in any environment. Microprocessor controlled measurement system and user-friendly interface (LCD display with simple keyboard) make EG-1 electrogustometer very handy and flexible in operation. Data obtained during measurements is stored in the internal device memory. After taste examinations measurement data can be transferred to a personal computer via inbuilt USB port for further analysis and storage. EG-1 can generate three predefined variously shaped current impulses: sinus-, saw- and rectangle-shaped. There is an optional possibility of creating own shapes of stimulus puls by the user. The electrical parameters of generated pulses are as follow: current amplitude 1-2000 microA regulated with 1 microA step, stimulus frequency 0(DC)-500 Hz regulated with 5 Hz step, controlable fulfillment factor and signal rise time (optional for automatic measurements). The operator can trigger the stimuli via a hand switch on the bipolar electrode (with gold-plated endings), via keyboard or via additional independent hand switch. Three years of experience collected during EG-1 exploitation allowed to design a new version of electrogustometer EG-2 with a touch panel and color graphical display.

Reinvestigation of the bitter compounds in carrots (Daucus carota L.) by using a molecular sensory science approach

In order to reinvestigate the key molecules inducing bitter off-taste of carrots ( Daucus carota L.), a sensory-guided fractionation approach was applied to bitter carrot extracts. Besides the previously reported bitter compounds, 6-methoxymellein (1), falcarindiol (2), falcarinol (3), and falcarindiol-3-acetate (4), the following compounds were identified for the first time as bitter compounds in carrots with low bitter recognition thresholds between 8 and 47 micromol/L: vaginatin (5), isovaginatin (6), 2-epilaserine oxide (7), laserine oxide (8), laserine (14), 2-epilaserine (15), 6,8-O-ditigloyl- (9), 6-O-angeloyl-, 8-O-tigloyl- (10), 6-O-tigloyl-, 8-O-angeloyl- (11), and 6-, 8-O-diangeloyl-6 ss,8alpha,11-trihydroxygermacra-1(10) E,4 E-diene (12), as well as 8-O-angeloyl-tovarol (13) and alpha-angeloyloxy-latifolone (16). Among these bitter molecules, compounds 9, 10, 13, and 16 were not previously identified in carrots and compounds 6, 11, and 12 were yet not reported in the literature.