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PubMed1976

Structure-activity studies on sulfamate sweeteners.

The structure-activity relationships governing sulfamate sweeteners are reviewed under the headings: size of the reduced ring, changes in the sulfamate function, substitution of hydrogen in the ring, and substitution of carbon in the ring and open-chain compounds. Fifteen compounds have been synthesized with a view to testing the limitations on structural changes which may be made within these categories without loss of sweetness. The presence of the grouping greater than CHN(R)SO3- is suggested as a necessary but not a sufficient condition for a compound to be sweet-tasting. Thus, the B center of the Shallenberger A-H,B theory of sweetness is best regarded as being -SO3- rather than -SO2- for sulfamates. Threshold levels and relative sweetness have been determined for seven sulfamates.

Amines↗
PubMedDate not supplied

Quantitative examination of taste deficiency due to radiation therapy.

A study was carried out with a Rion TR-03 type electro-gustometer for subjective and quantitative expression of the degree of taste deficiency due to radiation therapy and the effects of treatment. The changes of the electro-gustometric threshold due to irradiation were examined in patients who were divided into three groups: those receiving irradiation of the whole oral cavity, those receiving irradiation of the posterior tongue and the soft palate and those receiving irradiation of the gustatory nervous system. In the group receiving irradiation of the whole oral cavity, the threshold showed a tendency to increase when receiving 10 Gy/5 days, and the threshold became unmeasurable when more than 40 Gy/26 days was given. In the group receiving irradiation of the posterior tongue and the soft palate, almost no change of the threshold in the anterior was observed in spite of increasing irradiation doses. In the group receiving irradiation of the gustatory nervous system, the threshold in the intact hemicephalus did not changed even after irradiation, but a change was found on the pathological side. Based on these results, the authors originated a complication scoring system and a treatment scoring system both of which are divided into five stages. An electro-gustometric examination is used in order to provide effective treatment with a preserving function something which has been strongly desired for radiation therapy of cancer.

Brain Neoplasms↗
PubMed2006

Molecular definition of the taste of roasted cocoa nibs (Theobroma cacao) by means of quantitative studies and sensory experiments.

Sensory-guided decomposition of roasted cocoa nibs revealed that, besides theobromine and caffeine, a series of bitter-tasting 2,5-diketopiperazines and flavan-3-ols were the key inducers of the bitter taste as well as the astringent mouthfeel imparted upon consumption of roasted cocoa. In addition, a number of polyphenol glycopyranosides as well as a series of N-phenylpropenoyl-l-amino acids have been identified as key astringent compounds of roasted cocoa. In the present investigation, a total of 84 putative taste compounds were quantified in roasted cocoa beans and then rated for the taste contribution on the basis of dose-over-threshold (DoT) factors to bridge the gap between pure structural chemistry and human taste perception. To verify these quantitative results, an aqueous taste reconstitute was prepared by blending aqueous solutions of the individual taste compounds in their "natural" concentrations. Sensory analyses revealed that the taste profile of this artificial cocktail was very close to the taste profile of an aqueous suspension of roasted cocoa nibs. To further narrow down the number of key taste compounds, finally, taste omission experiments and human dose/response functions were performed, demonstrating that the bitter-tasting alkaloids theobromine and caffeine, seven bitter-tasting diketopiperazines, seven bitter- and astringent-tasting flavan-3-ols, six puckering astringent N-phenylpropenoyl-l-amino acids, four velvety astringent flavonol glycosides, gamma-aminobutyric acid, beta-aminoisobutyric acid, and six organic acids are the key organoleptics of the roasted cocoa nibs.

Cacao↗
PubMed2002

Dysgeusia due to an orthodontic wire: a case report.

A 14-year-old female developed gustatory disorder due to an orthodontic wire having pierced the right trigonal retromolar. The patient's complaints included traction pain on the right lower jaw, numbness on the right front half of the tongue and hypogeusia with the exception of sweet tastes. Possible causes of dysgeusia in this case were: (i) direct mechanical compression of a gustatory nerve by the orthodontic wire; and (ii) disturbance of blood supply to a gustatory nerve by edema that developed in nerve tissues around the wire. The patient's retention of a normal threshold for the recognition of sweet tastes is not fully understood.

Adolescent↗
PubMed2004

Taste function in elderly patients with unilateral middle ear disease.

OBJECTIVE: It is generally said that taste function deteriorates naturally with age. Taste function after middle ear surgery in elderly patients has not been clarified. MATERIAL AND METHODS: The taste function of the chorda tympani nerve on the normal and diseased sides was examined before and after middle ear surgery using electrogustometry in 79 patients aged>60 years, and the findings were compared with those in 228 young and middle-aged patients. RESULTS: The threshold of electrogustometry on the normal side increased significantly with increasing age (p<0.0001). The rate of thresholds that were off the scale was highest in the>70 years age group. The preoperative threshold on the diseased side increased significantly with increasing age in patients with chronic otitis media (p=0.0029) and cholesteatoma (p<0.0001). In patients with chronic otitis media, the postoperative threshold of the>60 years age group tended to be higher than that of the<60 years age group. CONCLUSIONS: These findings suggest that the taste function of the chorda tympani nerve deteriorated on the diseased side as much as on the normal side in elderly patients. Therefore, in most cases, we do not have to pay as much attention to the chorda tymapani nerve when performing surgery in elderly patients compared to young and middle-aged patients.

Adolescent↗
PubMed1994

The effect of sweeteners on bitter taste in young and elderly subjects.

The purpose of this study was to quantify the degree of reduction in perceived bitterness by sweeteners at both threshold and suprathreshold concentrations of bitter compounds. Detection and recognition thresholds were determined for six bitter compounds (caffeine, denatonium benzoate, magnesium chloride, quinine hydrochloride, sucrose octaacetate, and urea) in the absence and presence of several suprathreshold concentrations of five sweeteners. The sweeteners were: sucrose, aspartame, sodium saccharin, mannitol, and sorbitol. Polycose was also tested along with the sweeteners. The degree to which bitter thresholds were affected by the addition of sweeteners was dependent on the chemical classification of the sweeteners and their concentrations. In general, the natural sweeteners, sucrose, mannitol, and sorbitol, were more effective than the noncaloric sweeteners, aspartame and sodium saccharin, in elevating the detection and recognition thresholds of the bitter compounds. A sweetness intensity approximating that of 6% sucrose (0.175 M sucrose) or greater was required to elevate thresholds. For elderly subjects, sweeteners did not significantly elevate thresholds for denatonium benzoate and sucrose octaacetate. The degree to which sorbitol and sucrose can decrease the perceived bitterness intensity of suprathreshold concentrations of the six bitter compounds was also determined. The concentrations of sweeteners and bitter compounds were selected to be of moderate to high subjective intensity. The levels of sweeteners used in the mixtures were: sucrose (none, 0.946 M, and 2.13 M) and sorbitol (none, 2.1 M, and 3.68 M). Both sweeteners significantly reduced the bitterness ratings of almost every concentration of the six bitter compounds. The greatest reductions in bitterness were 87.0% for 0.192 microM denatonium benzoate mixed with 2.13 M sucrose and 84.7% for 1.8 M urea mixed with 3.68 M sorbitol.

Adult↗
PubMed1979

Taste detection and preferences in diabetics and their relatives.

In order to determine whether a generalized defect in glucose recognition exists in diabetes, taste detection and preference were measured in adult onset diabetics (AOD), juvenile onset diabetics (JOD), and healthy first-degree relatives of diabetics (NR). Controls (C) were age and sex matched nondiabetics without first-degree diabetic relatives. The AOD and NR gorups showed significantly higher glucose thresholds than their controls. In contrast, glucose threshold in JOD was not different from C. The AOD group also demonstrated a higher sucrose threshold than C. This difference was not present for JOD or NR groups. No difference in salt detection was seen in any of the groups. Taste preference was assessed by two choice situations and ratings of test solutions of varying concentrations. No significant difference in glucose or sucrose preference were noted, but both the AOD and NR groups preferred lower salt concentrations than C. These findings indicate that thery may be a widespread impariment of cellular glucose recognition in AOD and their relatives, while JOD have a specific beta cell defect.

Adolescent↗
PubMed1996

Are the tastes of polycose and monosodium glutamate unique?

To study whether Polycose and monosodium L-glutamate (L-MSG) have unique tastes differing from the traditional four basic tastes, chemosensory profiles were established for Polycose, L-MSG and a group of related compounds (sucrose, maltose, monosodium D-glutamate (D-MSG), sodium chloride, calcium chloride). Flavors were assessed using whole-mouth tests in human subjects with nose open or clamped to reduce olfactory input. Polycose (a mixture of glucose-based oligosaccharides) had a flavor consisting of an olfactory component and a maltose-like taste. L-MSG and D-MSG profiles differed from each other, and from NaCl and CaCl2. L-MSG had a lower threshold and a higher frequency of 'other' tastes than the D form. The data do not support a 'polysaccharide' taste, but suggest a chiral receptor site for 'umami' taste.

Adult↗
PubMed1991

Gustatory neural responses in preweanling mice.

Taste sensitivity of preweanling mice was studied by examining responses of the chorda tympani (CT) and glossopharyngeal (GL) nerves to various taste stimuli, and was compared to that of adult mice. In mice of 7-10 days of age, comparing to that of the CT nerve, threshold of the GL nerve for monosodium l-glutamate (MSG) was low, but those for sucrose and NaCl were high. Sensitivities to HCl and quinine-HCl were similar between the CT and GL nerves, although that to quinine-HCl was larger in the GL nerve than in the CT nerve in adult mice. Enhancement of MSG responses by addition of GMP was observed in the CT nerve but not in the GL nerve in this age group. In mice of 8-16 weeks of age, threshold of the GL nerve for MSG became higher but that for NaCl became lower. Enhancement of MSG responses by addition of GMP appeared also in the GL nerve. Inhibition of NaCl responses by amiloride was observed in the CT nerve. These results suggest that, in mice, the GL nerve is important taste input for umami substances especially during the preweanling period, whereas the CT nerve is for sweet and salty substances. Properties of umami and salt receptor systems change during the postweanling period.

Animals↗
PubMed1995

Nerve growth factor facilitates conditioned taste aversion learning in normal rats.

Chronic intracerebroventricular (i.c.v.) infusion of 3.2 micrograms/day of nerve growth factor (NGF) in normal rats elevated choline acetyltransferase (ChAT) activity of the striatum, medial septum, and basal forebrain and improved performance of a conditioned taste aversion (CTA) task. Relative to bovine serum albumin (BSA) or Cytochrome C treatments, NGF treatment facilitated acquisition and prolonged extinction of a lithium chloride (LiCl)-induced saccharin aversion. This facilitation was evident at saccharin/LiCl intervals ranging up to 1 h. Also, NGF treatment did not increase reactivity to LiCl-induced illness and neither shifted detection thresholds nor altered hedonic reactions to taste stimuli, indicating that NGF did not produce simple changes in sensory function. NGF treatments that elevate ChAT also facilitate memory of CTA in normal, adult rats.

Animals↗
PubMed1997

Effect of amiloride on suprathreshold NaCl, LiCl, and KCl salt taste in humans.

The purpose of this study was to investigate normal variances in the response magnitudes of suprathreshold concentrations of NaCl, LiCl, and KCl salts and amiloride on the anterior human tongue. Random equimolar concentrations of salt solutions were delivered to spatially matched flow chambers of 20 volunteers at 3 different sessions. A cross-modal magnitude matching procedure was used to scale salt taste-intensity judgments. After each salt test, amiloride (100 microns) was delivered for 5 min and the test was repeated. At least-square regression analysis of each subjects' function between log molar concentration and log response demonstrated that every subject scaled the dynamic range of salts. There were no differences in either the mean regression or intercept among the 3 salts. Repeated-measures analysis demonstrated a statistical effect of amiloride on the before/after difference in the regression (p = 0.02) and intercept (p < 0.0001) of NaCl and LiCl functions. Postamiloride NaCl and LiCl coefficient of variance of response was increased. Amiloride had no effect on the before/after difference in the regression and intercept of KCl power functions or the variance of response. The results suggest that, after amiloride, NaCl and LiCl suprathreshold salt taste intensities are reduced, but there are individual variabilities of reduced intensity that are never completely eliminated.

Adult↗
PubMed1986

Chemosensory properties of sour tastants.

In Experiment 1, a taste quality fractionation procedure was used to establish the degree to which sour and non-sour taste sensations are elicited by six concentrations of each of seven acids: citric, hydrochloric, sulfuric, lactic, malic, phosphoric and tartaric. In general, the acids differed significantly in their ability to elicit sour, salty and bitter sensations, with sulfuric and hydrochloric acids producing the smallest proportions of perceived sourness. Bitterness was found to be the largest non-sour sensation produced, followed by saltiness. The perceived taste qualities of the acids were stable across a wide range of concentrations. In Experiment 2 the extent to which the vapors of these test acids produce detectable intranasal non-gustatory sensations at concentration levels used in many human taste experiments was examined. All acids induced clear intranasal sensations at concentration levels used in some suprathreshold taste paradigms. The results suggest that a number of measures of sour taste sensation may be confounded by non-sour chemosensory factors, including intranasal stimulation.

Acids↗
PubMed1997

Influence of stimulus duration on a regional measure of NaCl taste sensitivity.

The present study demonstrates that perithreshold temporal integration occurs in the human taste system across stimulus durations ranging from 200 to 1500 ms in a manner analogous to that seen in other major sensory systems. Thus, the notion that gustation is comparatively insensitive to temporal stimulus parameters at threshold levels is disproved.

Adult↗
PubMed1976

Blood pressure, salt preference, salt threshold, and relative weight.

This study was performed to observe the relationships of salt preference, salt threshold, the relative weight to blood pressure. Three groups were selected from 4,800 school children on the basis of mean blood pressure: less than or equal to fifth percentile, in the area of the 50th percentile, and greater than or equal to 95th percentile. Salt threshold was determined by titrating, on each subject's tongue, solutions ranging from 1 to 60 millimols/liter of sodium chloride. Salt preference was tested by the addition of salt by each subject to unsalted tomato juice and beef broth according to individual taste. The samples were then analyzed for sodium concentration. The coefficient of correlation for the amount of salt added to juice and broth was significant (r=0.63). There was no relationship of salt threshold to preference, nor did threshold or preference relate to blood pressure. Relative weight was related to blood pressure range being the most obese.

Adolescent↗
PubMed1991

On the discrimination of missing ingredients: aging and salt flavor.

This study reports on the ability of young, middle-aged, and elderly persons to discriminate the presence-absence of the salt flavoring in a published recipe for a soup. Although all but one young person tested was able to make this discrimination above chance level, more than half of each of the two older groups failed to do so. Both the discrimination score and the absolute threshold for NaCl in water solution correlated significantly with age over a span from 18 to 89 yrs. These results add to previous ones from a similar study of the discrimination of an aromatic spice, marjoram (Cain et al., 1990), in demonstrating that taste and smell weakness revealed in recent psychophysical tests can reveal themselves in the perception of everyday food and beverage preparations. A secondary study compared thresholds for NaCl in water with NaCl thresholds in the presence of tomato, the principal ingredient of the published recipe. These thresholds, presumably because of "mixture suppression" of tastes, were from seven to ten times higher than thresholds in water. Although thresholds for young and old were more alike in the tomato medium than in water, the elderly nevertheless needed over twice as much salt concentration than did the young just barely to appreciate its presence. Computer evaluation of the salt content of a large number of soup recipes revealed that (a) the salt content of the tomato soup we used to study discrimination was reasonably representative of other published recipes for tomato soups and (b) that the salt content of the average of these tomato soup recipes was greater than that of the average of non-tomato soup recipes.

Adult↗
PubMed2000

Neohesperidin dihydrochalcone is not a taste enhancer in aqueous sucrose solutions.

Neohesperidin dihydrochalcone (NHDC) is an intensive sweetener, obtained by alkaline hydrogenation of neohesperidin. In this investigation a supposed taste enhancing effect of this substance was tested. A three-step procedure was used. In the first experiment, using a pool of 31 subjects, NHDC and sucrose detection thresholds were measured. In the second experiment, psychophysical functions for both tastants were determined. Then, 15 participants closest to the group threshold who, in addition, had produced monotonic psychophysical taste functions were selected to participate in the next two experiments. In the third experiment, taste enhancement was tested. Three psychophysical sucrose functions were constructed, one with a near-threshold amount of NHDC added to each of seven sucrose concentrations, one with a near-threshold amount of sucrose added (control 1) and one without any addition (control 2). No difference was found between the NHDC-enriched sucrose function and the sucrose-enriched sucrose function. Finally, in experiment 4, differential threshold functions were constructed with either NHDC or sucrose added. Neither the overall shape of the functions nor a comparison of the points of subjective equality showed enhancement. It was concluded that weak NHDC does not enhance the taste of aqueous sucrose solutions.

Adolescent↗
PubMed2003

Amiloride is an ineffective conditioned stimulus in taste aversion learning in C57BL/6J and DBA/2J mice.

The epithelial sodium channel (ENaC) blocker amiloride has been shown to increase the behaviorally measured NaCl detection threshold in mice. In this study, a conditioned taste aversion (CTA) paradigm was used to examine whether 100 microM amiloride has a perceptible taste that could contribute to this observed decrease in behavioral responsiveness. Eighty-four C57BL/6J (B6) and 64 DBA/2J (D2) mice were divided into eight groups (n=8-12 per group), in which half received an injection of 0.15 M LiCl (2 mEq/kg) and the other half an equivalent saline injection, in three conditioning trials. The four conditioned stimuli were 100 microM amiloride hydrochloride, water, 0.1 and 0.3 M NaCl. Neither strain demonstrated acquisition of a CTA to amiloride in a brief-access (BA) taste test (5 s trials in the gustometer). Although 0.3 M NaCl is inherently aversive, its pairing with LiCl led to significantly further decreases in licking during the BA test on salt trials in both strains. The D2 strain clearly avoided 0.1 M NaCl, whereas avoidance of this stimulus was more equivocal in B6 mice. The inefficacy of amiloride to serve as a conditioned stimulus in taste aversion learning involving three LiCl pairings suggests that the effects of this ENaC blocker on taste-related behavioral responses to NaCl are likely due to its pharmacological interference with sodium taste transduction.

Amiloride↗