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PubMed1989

Taste discrimination of traditional and 'health' modified recipes.

Beef stew and sponge cake were prepared utilising traditional recipes and recipes modified in accordance with NACNE, National Advisory Committee on Nutrition Education guidelines (1983). Triangle tests were performed to determine whether subjects could discriminate between samples prepared using the traditional recipes. Thirty subjects (15 men and 15 women) participated. No significant differences could be established between the traditional and modified stew or sponge cake in terms of eating quality. Modification of traditional recipes by reducing sugar, fat and salt and increasing the fibre content without affecting the overall sensory quality that the consumer expects is an ideal way of achieving recommended dietary goals.

Adolescent↗
PubMed1990

Effects of hydrochlorothiazide and amiloride on salt taste and excretion (intake).

The effects of hydrochlorothiazide (HCTZ) and amiloride on salt excretion (intake) and taste were examined in 73 normotensive adults (aged 18 to 56) who were randomly assigned to receive 50 mg/day of HCTZ (n = 24), 5 mg twice daily of amiloride (n = 24) or placebo (n = 25) for 8 weeks. Two and three week placebo periods preceded and followed active treatment, respectively. Relative to baseline, significant increases in sodium excretion (intake) of 31%, 53% and 30% were observed in subjects receiving HCTZ after 2, 4 and 8 weeks of treatment, respectively. An identical follow-up study with 16 subjects replicated the sodium excretion (intake) findings, but failed to reveal the source of the extra dietary sodium. Doubling the dose of amiloride in 11 additional subjects led to higher aldosterone excretion relative to thiazide-treated subjects, but did not increase salt excretion (intake) over a four week period. Only amiloride-treated subjects displayed significant increases in salt taste sensitivity. The increased sodium intake in HCTZ-treated patients may partially offset the desired effects of therapy and exacerbate potassium wasting.

Adolescent↗
PubMed2004

Chlorinous flavor perception in drinking water.

Chlorinous flavors at the tap are the leading cause of customers' complaints and dissatisfaction with drinking water. To characterize consumer perception and acceptance to chlorinous tastes, extensive taste testing was performed with both trained panelists and average consumers. Taste testing with trained panelists showed that chlorine perception is underestimated by disinfectant flavor thresholds reported in the literature. However, trained panelists significantly overestimate the average consumer's ability to perceive chlorine. In addition, consumer perception seems to be influenced by the chlorination practices of the country they live in. Among water quality characteristics that may influence chlorine perception, temperature was not found to induce any significant change. The influence of total dissolved solids (TDS) on chlorine perception remains unclear and, as reported elsewhere, background tastes such as musty, may significantly impact chlorine threshold.

Chlorine Compounds↗
PubMed2006

Taste differentiation in the context of suckling and independent, adultlike ingestive behavior.

The present study compared intake of sweet (saccharin), bitter (quinine), and neutral (water) tastants available either in the context of suckling behavior through a surrogate nipple or independent adultlike feeding through an intraoral cheek cannula in 3-hr-old newborn rats lacking any suckling experience and 24-hr-old rats with regular experience with the dam's nipple. The new technique of online monitoring of fluid flow was applied for assessment of the temporal patterns of ingestion. Newborn and 1-day-old rats tested in the context of suckling behavior showed extremely low intake of quinine, moderate intake of water, and high intake of saccharin. In the same way, they demonstrated low intake of quinine and high intake of saccharin in the context of independent feeding, but intake of water was also high and comparable to that of saccharin. Suckling rats attained higher efficacy of fluid extraction from nipple than pups drinking from cannula. The differential responsiveness to quinine, saccharin, and water in suckling rats was also manifested through attachment behavior, with pups spending less time on the nipple providing quinine and more time on the nipple with saccharin than on the nipple providing water. These results suggest that neonates show taste differentiation as early as 3 hr after birth, and that this taste differentiation is more pronounced in the context of suckling behavior than in the context of adultlike, independent ingestion.

Age Factors↗
PubMed1979

Salt taste adaptation: the psychophysical effects of adapting solutions and residual stimuli from prior tastings on the taste of sodium chloride.

The paper reviews how adaptation to sodium chloride, changing in concentration as a result of various experimental procedures, affects measurements of the sensitivity, intensity, and quality of the salt taste. The development of and evidence for the current model that the salt taste depends on an adaptation level (taste zero) determined by the sodium cation concentration is examined and found to be generally supported, despite great methodological complications. It would seem that lower adaptation levels elicit lower thresholds, higher intensity estimates, and altered quality descriptions with predictable effects on psychophysical measures.

Adaptation, Physiological↗
PubMed2002

Electrogustometric thresholds: relationship to anterior tongue locus, area of stimulation, and number of fungiform papillae.

It is well established that, on the anterior tongue, thresholds for chemical tastants are inversely related to the number of fungiform papillae. However, it is not known whether this is the case for thresholds for electrical currents presented to the lingual surface. In this study, electrical thresholds for 16 subjects were determined at four left-side anterior lingual locations: tongue tip (TT), a region 1.7 cm posterior to the TT, a region 3.4 cm posterior to the TT, and a region 1.7 cm from the TT along the lateral margin. Two electrode sizes (12.5 mm2 and 50 mm2) were employed for the anodal current, and stimulus duration was held constant at 0.5 s. The number of fungiform papillae was determined using videomicroscopy. Analogous to what is seen with chemical stimulation, an inverse relationship was present between the mean electrical thresholds, expressed in terms of current density, and the number of papillae within the stimulated regions. The TT-which has the highest density of fungiform papillae--was found to be more sensitive than the other tongue regions evaluated. Also paralleling chemical thresholds, the mean electrical threshold values were lower (i.e., sensitivity was higher) at a given tongue locus for the 50-mm2 than for the 12.5-mm2 stimulus area. Overall, this study demonstrates that thresholds for electrical stimulation vary across discrete regions of the anterior tongue and are specifically related to the number of fungiform papillae within the stimulated regions. These observations provide additional support for the hypothesis that lingual sensations induced by low levels of electrical current are mediated by the taste system.

Adolescent↗
PubMed1994

Taste responses of bullfrog to pungent stimuli.

Taste responses of bullfrogs to various pungent compounds and taste substances were electrophysiologically recorded from glossopharyngeal nerves. The threshold concentrations were approximately 10(-7) M for piperine, approximately 10(-6) M for capsaicin and approximately 10(-4) M for allyl isothiocyanate. At any concentration examined, piperine was more potent than capsaicin. Both piperine and capsaicin elicited desensitizing responses, but the taste receptors recovered from the desensitization within 10 min after washing with deionized water. Cross-adaptation experiments revealed that capsaicin only partially desensitizes receptors for piperine, L-leucine, HCl or quinine. Perfusion of the lingual artery with a solution containing no added Ca decreased the responses to capsaicin. Such a solution has been shown to suppress the taste nerve responses by blocking synaptic transmissions between taste cells and taste nerves [8]. These results suggest that the gustatory effects of capsaicin are different from its pharmacological effects on sensory neurons. It is likely that capsaicin and other pungent compounds, when they act as seasonings, stimulate taste cells rather than the free nerve endings of the sensory neurons.

Adaptation, Physiological↗
PubMed2001

IP(3) receptor type 3 and PLCbeta2 are co-expressed with taste receptors T1R and T2R in rat taste bud cells.

The Ca(2+) signaling cascade has been reported to be activated by many tastants in vertebrate taste systems. Recently we have shown that G(i2) and phospholipase Cbeta2 (PLCbeta2) are co-expressed in a subset of taste bud cells and are possibly involved in Ca(2+) triggering of taste signaling in rats. We report here that, as a component downstream of PLCbeta2, the type 3 isoform of the inositol 1,4,5-trisphosphate (IP(3)) receptor (IP(3)R3) is specifically expressed in the same cells as PLCbeta2 in rat taste buds. We also show that cells expressing rT2R9, a probable cycloheximide receptor, are included among PLCbeta2- and IP(3)R3-positive cells, as in the case of rT1R2, a different type of taste receptor. Our findings indicate that PLCbeta2 and IP(3)R3 co-localize together with G(i2) as downstream components of two different types of taste receptors, T1R and T2R, in taste bud cells.

Animals↗
PubMed1984

Salt taste sensitivity and stimulus volume: sips and drops. Some implications for the Henkin taste test.

Various presentation procedures and stimulus volumes were compared in their effect on salt taste sensitivity. For sodium chloride (NaCl) stimuli pipetted onto the tongue, subjects had comparable measured sensitivity to 10 ml and 1 ml volumes but a reduced sensitivity to 0.1 ml volumes. The greatest sensitivity was achieved with 10 ml sipped volumes. Modification of the Henkin dropwise triangular taste test, by increasing the stimulus volumes, increased subjects' sensitivity. Only the 1 ml pipette presentation increased the sensitivity of the Henkin procedure, albeit slightly, to the detection of changes in taste sensitivity, the purpose for which the procedure was actually designed. Such modification did not perturb salivary NaCl levels more than the regular Henkin procedure, so it would not be expected to introduce sensitivity drift.

Adolescent↗
PubMed2006

Detection of NaCl and KCl in TRPV1 knockout mice.

Both amiloride-sensitive and -insensitive mechanisms contribute to NaCl taste transduction. The amiloride-sensitive mechanism relies on the epithelial Na(+) channel ENaC, which is widely expressed on the apical membrane of fungiform taste cells. The amiloride-insensitive mechanism, which predominates in circumvallate and foliate taste buds, was recently reported to involve a variant of the nonselective cation channel TRPV1. We performed 2-bottle preference and threshold experiments with TRPV1 knockout mice and wild-type (C57BL/6J) controls to test for NaCl preference and detection thresholds in the presence and absence of amiloride. Surprisingly, TRPV1 knockout mice not only detected NaCl in the presence of amiloride but they preferred NaCl over water at concentrations avoided by the wild-type mice. NaCl detection thresholds were between 2 and 3 mM for both genotypes. Amiloride increased the detection thresholds of wild-type mice but not knockout mice. The knockout mice also preferred 100 mM KCl compared with wild-type controls, suggesting that TRPV1 receptors may mediate a general aversive response to salts. Analyses of consumption data also revealed that TRPV1 knockout mice ingested more of the NaCl, with and without amiloride, and KCl solutions than the wild-type mice. However, comparisons of preference ratios and consumption volumes indicated that both wild-type and TRPV1 knockout mice avoided citric acid in quite a similar manner, suggesting that TRPV1 receptors do not mediate the detection of citric acid. These data, taken together, suggest that additional mechanisms must contribute to the amiloride-insensitive NaCl response.

Amiloride↗
PubMed1993

Bitter taste of enzymic hydrolysates of casein. I. Isolation, structural and sensorial analysis of peptides from tryptic hydrolysates of beta-casein.

beta-Casein A2 was isolated from milk of a homozygous cow and hydrolysed with trypsin. The hydrolysate was separated by RP-HPLC into 18 peptides, all but one of which could be attributed to the sequence of beta-casein on the basis of the amino acid composition. Some peptides overlapped. In total, they represented about 97% of the protein sequence. Only three peptides had a bitter taste, namely I49-N68 (recognition threshold 1.0 mg/ml, 0.45 mmol/l), I49-K97 (1.5 mg/ml, 0.28 mmol/l) and G203-V209 (0.175 mg/ml, 0.23 mmol/l). The contribution of the three peptides to the overall bitterness of the beta-casein hydrolysate (2.67 mg/ml) was about 11, 21, and 60%, respectively. Peptide I49-K97 was present in the hydrolysate together with its fragments I49-N68 and S69-K97. Remarkably, the smaller and more hydrophobic fragment I49-N68 was less bitter than I49-K97 on a molar basis, whereas the larger and more hydrophilic fragment S69-K97 had a neutral taste. These results show that in the case of larger peptides neither hydrophobicity nor size are responsible alone for bitter potency, but that conformational parameters must be of great importance. Furthermore, it can be concluded that only a part of the structure is responsible for the contact with the receptor. The bitterness of G203-V209 is discussed in connection with related synthetic peptides in the literature.

Amino Acid Sequence↗
PubMed1980

The role of endorphins in animal learning and behavior.

The present review examined the influence of endorphins in animal learning and behavior. It was suggested that in learning paradigms involving stress, the stressor elicits the release of endorphins. Given the evidence on endorphin-mediated, stress-induced analgesia, it was further suggested that the stress-induced release of endorphins modulates the aversiveness of the stressor, and as such, affects the learning based on this stressor. A number of learning paradigms, e.g., the conditioned emotional response, preference for signaled shock, conditioned taste aversions, and learned helplessness, were presented in support of this mediation of learning by the endorphins. A possible interaction between the endorphins and adrenocorticotropic hormone was offered as a physiological basis for this mediation.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Taste interaction of styrene/ethylbenzene mixtures in an oil-in-water emulsion.

Styrene and ethylbenzene are present in detectable amounts in polystyrene packaging materials and migration of these compounds may cause a taint of the packed food. The effect of mixtures of styrene and ethylbenzene on the detection threshold concentration in a 5% oil-in-water emulsion was investigated with the constant stimulus differences test. The detection threshold concentrations of the individual compounds in the emulsion were found to be 1.0 ppm for styrene and 3.0 ppm for ethylbenzene. Linear regression of the percentages of correct answers and the logarithm of the sum of the concentrations of both compounds in the mixtures expressed as fractions of their threshold concentration gave the following relationship: % of correct answers = 42.5 x log (sum of threshold fractions) +74.8 (r = 0.87). Calculation of the sum of threshold fractions at the 75% point of correct answers gave a value of 1.0, which clearly indicates that the effect of mixing of styrene and ethylbenzene is additive at sub-threshold levels in a 5% oil-in-water emulsion.

Benzene Derivatives↗
PubMed2002

Gustatory processing in thoracic local circuits of locusts.

Recent reviews highlight a longstanding controversy about how different taste qualities are coded in the CNS. To address this issue, we have analyzed gustatory coding in the relatively simple and accessible nervous system of the locust, in which neural responses and gustatory elicited behavior are readily comparable. The intracellular responses of a population of spiking local interneurons in the metathoracic ganglion that receive monosynaptic inputs from chemosensory afferents were analyzed in response to stimulation with droplets of four behaviorally relevant chemicals: sodium chloride, sucrose, lysine glutamate, and nicotine hydrogen tartrate. There was a significant positive correlation between chemical concentration and response duration and the number of spikes evoked in 81% of interneurons sampled. The threshold of sensitivity to different chemicals varied but was consistent between all interneurons tested, being most sensitive to nicotine hydrogen tartrate and least sensitive to sucrose. Each interneuron responded similarly to specific chemicals at single concentrations. Interneurons that responded phasically to one chemical responded similarly to others, whereas interneurons that responded phasotonically to one stimulus also did so to others. Hindleg motor neurons also responded in a concentration-dependent manner to all test chemicals. Therefore, we found no interneurons or motor neurons that responded only to specific chemicals. We discuss the responses of the local circuit neurons in relation to the known chemically evoked behavioral responses of locusts and suggest that the aversiveness of a chemical, rather than its identity, is encoded directly in the local circuits.

Action Potentials↗
PubMed1978

Correction of taste abnormality of malignancy with intravenous hyperalimentation.

A complete remission of widely metastatic bladder carcinoma was obtained with chemotherapy in a 41-year-old man. Severe persistent anorexia led to a 33% weight loss. The anorexia correlated with an elevated sucrose recognition threshold. Following 16 days of intravenous hyperalimentation, taste sensation returned to normal, anorectic symptoms cleared, and weight gain and positive nitrogen balance resulted. There was no stimulation of tumor growth. Restoration of nutritional deficits with intravenous hyperalimentation can improve taste function and appetite so that adequate oral alimentation can be tolerated.

Adult↗
PubMedDate not supplied

[Taste receptor response to sodium chloride and natriuresis in the workers and employees of an industrial enterprise].

Studied in the course of one-stage epidemiologic survey of 1191 individuals were the threshold of gustatory sensitivity to table salt and nycterine natriuresis, relation of these indices to dietary habits, some risk factors for cardiovascular disorders and clinical parameters. Differing relations were established between gustatory sensitivity to table salt and natriuresis and age and gender of the examinees, the level of blood pressure, aggravated heredity in respect of arterial hypertension, smoking and alcohol abuse, this enabling one to embark upon a differential approach to dietetic correction of salt consumption.

Adult↗
PubMed2002

Changes in gustatory sense during pregnancy.

Changes in gustatory sense were investigated in 97 pregnant women and in 30 healthy, non-pregnant women who served as controls. All 97 pregnant women completed a questionnaire regarding taste changes and 32 of them underwent serial tests of gustatory function, including electrogustometry and testing with filter paper disks placed over the areas of the chorda tympani nerve and glossopharyngeal nerve. All gustatory testing was performed by the same person. In addition, serum levels of trace elements were measured in 72 of the pregnant women. Of the 97 pregnant women, 90 (92.8%) reported in the questionnaire that they had experienced some type of change in taste during pregnancy, usually a change in sour taste (59 women; 65.6%). Pregnant women had higher gustatory thresholds than non-pregnant women, with an especially marked decrease in gustatory function being noticed in the first trimester. Although serum zinc levels decreased in pregnant women between the second and third trimesters, zinc levels were in the normal range in the early stage of pregnancy. Thus, it is difficult to explain dysgeusia in the early stage of pregnancy as being associated with a deficiency of zinc. The decrease in gustatory function during the first trimester is considered to be due to the notable changes in secretion of hormones that occur during this stage.

Adolescent↗
PubMed1990

Taste detection and discrimination performance of rats following selective desalivation.

Taste sensitivity and responsivity, two-tastant and taste-mixture discrimination performance, and taste preferences were examined prior to and after the selective desalivation of 48 male Long-Evans rats. Altered preference behavior was observed in rats after removal of the major salivary glands, as well as after removal of only the submandibular-sublingual complexes. In 9 of 12 desalivated rats, decreased sensitivity and increased responsivity to near-threshold sodium chloride solutions were observed, although these changes were less than one-half an order of magnitude. No between-group differences in performance on two-tastant and taste-mixture discrimination tasks were observed. These results suggest that decrements in absolute sensitivity do not result in concomitant deficits in the discrimination of taste qualities.

Animals↗