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PubMed1977

[Investigation about the taste of di, tri- and tetrahydroxy fatty acid].

Two diastereomeric 9, 10-dihydroxystearic acids, four diasteromeric 9,10,12-trishydroxystearic acids, a mixture of diastereomeric 9,10,12,13-tetrahydroxystearic acids, a mixture of 9.12,13,-trihydroxy-10 trans- and 9,10,13-trihydroxy-11-trans-octadecenoic acids (tri-OH-mixture from lipoxygenase catalysis) and the hydrogenated tri-OH mixture were tested for bitter taste. Only the tri - and tetrahydroxy acids are bitter. The taste thresholds of the saturated tri- and tetrahydroxy acids are in the range from 1.0--4.3 micron ol/ml. There are no significant differences in the taste thresholds between the four diastereomeric 9,- 10,12-trihydroxy acids. The double bond in the trihydroxy acids from the lipoxygenase catalysis enhances the bitter taste 3-fold.

Humans↗
PubMed2004

Effects of caloric deprivation and satiety on sensitivity of the gustatory system.

BACKGROUND: Sensitivity of the gustatory system could be modulated by a number of short-term and long-term factors such as body mass, gender, age, local and systemic diseases and pathological processes, excessive alcohol drinking, drug dependence, smoking, composition of oral fluid, state of oral hygiene, consumption of some foods among many others. A few studies have demonstrated the effects of hunger and caloric satiety on sensitivity of the gustatory system in obese humans and animals. The aim of the present study was to assess the effects of short-term caloric deprivation and satiety on recognition taste thresholds of healthy, non-smoking, non-drinking, non-obese young male subjects. The two-alternative forced-choice technique was used to measure taste threshold. RESULTS: Recognition thresholds for sucrose and salt were significantly lower during fasting state than after a meal (t = 2.23, P < 0.05, and t = 2.86, P < 0.02, respectively) while the values of recognition thresholds for bitter substances in fasting state and after caloric loading did not differ significantly. CONCLUSIONS: Short-term caloric deprivation in our study model was associated with increased taste sensitivity to sweet and salty substances compared to satiated state while taste sensitivity to bitter substances was not affected by the conditions of measurements. Selective modulation of sensitivity of the gustatory system might reflect the different biological importance of salty, sweet and bitter qualities of taste.

Adult↗
PubMed1998

Sweet and bitter taste discrimination in primates: scaling effects across species.

The adaptive nature of taste discrimination has been questioned on the basis that marked differences in taste thresholds for soluble sugars across mammals may not correspond to distinct dietary tendencies and further imply inaccurate prediction of the energetic value of food. Appropriate models of the evolution of taste, however, require not only consideration of adaptations to diet but also recognition of phylogenetic and allometric effects. Here, we analyse these factors in primates exhibiting various diets and covering a wide range of body weights. Taste thresholds for sucrose and fructose are negatively related to body weight overall but are commonly similar in closely related species irrespective of dietary specialisations. By contrast, major interspecific differences in the discrimination of quinine hydrochloride are observed in the absence of any allometric effect. We propose that this asymmetrical differentiation of sweet and bitter taste discrimination reflects divergent evolutionary trends for meeting energy requirements and for avoiding noxious substances.

Animals↗
PubMed1982

Taste acuity, plasma zinc levels, and weight loss during radiotherapy: a study of relationships.

Thirty-five patients who were to undergo radiotherapy and 13 normal subjects were evaluated with taste questionnaires, taste acuity tests, and plasma zinc analyses. The studies were repeated on the patients in the fifth week of radiotherapy. The mean taste thresholds for NaCl (salt), sucrose (sweet), HCl (sour), and urea (bitter) were elevated and the plasma zinc levels were lower (77.2 +/- 11.8 vs. 94.6 +/- 30.1 g/100 ml, p = 0.055) for the patients than for the controls. However, there was not a significant correlation between the taste thresholds and plasma zinc levels at any time. The mean weight loss experienced by the 14 patients who reported subjective taste alteration in the fifth week was 3.1 kg versus 0.1 kg (p = 0.005) for those who did not report taste alteration. The data suggest that alterations in taste acuity, but not plasma zinc levels, are associated with weight loss during radiotherapy.

Adult↗
PubMed1975

[Bitter peptides isolated from corn protein zein by hydrolysis with pepsin (author's transl)].

Eight peptides with bitter taste were isolated from a hydrolyzate of the corn protein zein using several chromatographic procedures. The peptides have the following amino acid sequences and taste thresholds (muM/ml): Ala-Ile-Ala (50-100), Ala-Ala-Leu (50-100), Gly-Ala-Leu (50-100), Leu-Glu-Leu (2.5-3.5), Leu-Glu-Leu (8-12), Leu-Val-Leu (1.5-2.5), Leu-Pro-Phe-Asn-Gln-Leu (0.1-0.2), Leu-Pro-Phe-Ser-Gln-Leu (0.1-0.2). The threshold for bitter taste decreases with increasing number of hydrophobic side chains (greater than or equal to C3) in the peptide. It increases in the presence of hydrophilic side chains to their polarity.

Amino Acid Sequence↗
PubMed1993

[A study of hygienic standard for titanium in the source of drinking water].

The smell and taste thresholds of titanium in water were tested. The results indicated that the concentration of smell and taste thresholds for Titanium were 4.329mg/L and 3.332mg/L respectively. The threshold below value of autopurification was 0.1mg/L. The toxicity assessment showed that the acute toxicity of titanium by oral route was of low order according to the toxicity classification. There was no obvious cumulative effect, nor was there mutagenesis demonstrable. Chronic toxicity test of titanium in rats showed that the maximum non-effective concentration was 1.08mg/L. It is suggested that the maximum allowable concentration of titanium in drinking water may be 0.1 mg/L.

Animals↗
PubMed1983

Assessment of the zinc nutritional status of selected elderly subjects.

Elderly participants (with a mean age range of 71 to 75 years) residing in two housing complexes in Tuscaloosa, Alabama, can generally be characterized as predominantly women with a low socioeconomic status living alone. A majority of the participants consumed less than the RDA for food energy. The protein intake was nearly equal to or exceeded the RDA; however, the mean intake of zinc was only half of the RDA. The mean hair zinc concentration of the participants corresponded with the levels reported for this age group by other researchers. Their mean taste thresholds were higher (lower taste acuity) than those reported for young adults. Detection thresholds decreased as the ages of the participants increased. The taste acuity of the participants resembled that of groups of elderly studied by other investigators. A precise definition of low zinc status measurements among the elderly is not available at this time. However, the low hair zinc concentrations and taste acuity, compounded with the low zinc intake, indicate that this population is at risk for zinc deficiency.

Aged↗
PubMed2003

The effects of taste and consistency on swallow physiology in younger and older healthy individuals: a surface electromyographic study.

Recent studies done on healthy older individuals have demonstrated elevated taste thresholds for sweet, sour, and salty taste. At suprathreshold levels, such individuals have also shown less ability to discriminate between different intensities of the same tastant. This study was designed to provide information on swallow timing and muscle contraction intensity variables in healthy older people during swallowing of liquid and cottage cheese consistencies in 3 taste conditions (sweet, salty, and sour). Taste and consistency were incorporated in the design of this study to determine not only the effect of taste and consistency independently, but also the effects of taste and consistency in combination. Surface electromyography (EMG) at 3 sites--the orbicularis oris inferior region, submental muscle region, and infrahyoid muscle region--were included in the study. Results revealed that the start of submental muscle activation was significantly later in older participants than in younger participants. The 3 taste conditions had higher EMG levels and shorter activation times than the no-taste condition, although different taste conditions and different muscle sites were affected differently. With thicker consistency, substantially increased EMG amplitude and duration were noted for all three sites. A more pronounced effect of taste was manifested as earlier submental or infrahyoid muscle activation when the three tastants were added to a thicker consistency. Interaction of taste, consistency, and age was also noted for onset time at the submental and infrahyoid sites.

Adolescent↗
PubMed1986

Role of zinc supplementation in type II diabetes mellitus.

Zinc is required for normal immune function and taste acuity and enhances the in vitro effectiveness of insulin. Impaired immune function and taste have been reported in diabetic subjects, and decreased serum zinc levels and hyperzincuria occur in some diabetic subjects and animals. Subjects with type II diabetes were examined to determine whether the similar effects of zinc depletion and diabetes are causally related. Low serum zinc levels were found in 16 of 180 subjects (9 percent). There was no correlation between serum zinc and glycosylated hemoglobin levels. Natural killer cell activity did not differ between diabetic subjects (n = 28) and control subjects (n = 38) and did not correlate with serum zinc levels. T lymphocyte response to phytohemagglutinin was lower in diabetic subjects than in control subjects (70 +/- 10 versus 103 +/- 7 X 10(3) counts per minute) but was not lowest in those with the lowest zinc levels. Taste thresholds for hydrochloric acid, sucrose, sodium chloride, and urea were elevated in diabetic subjects (n = 28) versus control subjects (n = 10), but thresholds did not correlate with glycosylated hemoglobin or serum zinc levels. Zinc supplementation in nine diabetic subjects had no effect on the glycosylated hemoglobin level, natural killer cell activity, or taste thresholds, but it did increase mitogen activity in those with the lowest initial phytohemagglutinin responses. It is concluded that zinc deficiency occurs in a subset of subjects with type II diabetes but is not related to diabetes control and does not explain decreased taste acuity. Zinc deficiency may play a role in abnormal immune function in type II diabetes mellitus.

Adult↗
PubMed2003

Sugar intake, taste changes and dental health in Crohn's disease.

BACKGROUND: An increased intake of sucrose has been reported in patients with Crohn's disease (CD). Since subclinical zinc deficiency reduces taste perception for sweet, we investigated taste perception, sucrose intake and plasma zinc levels as well as dental status in CD patients. METHODS: Carbohydrate intake and plasma zinc levels were assessed in 24 CD patients and 24 age-matched controls (Con). Taste threshold for sucrose, oral hygiene and caries prevalence were evaluated. RESULTS: In CD a higher sucrose intake (CD 107.1 +/- 27.7 vs. Con 71.9 +/- 13.7 g/day; p < 0.001), a higher taste threshold for sweet (CD 7.31 vs. Con 2.91 g/l; p < 0.001) and lower plasma zinc levels (CD 11.5 +/- 1.5 vs. Con 13.5 +/- 2.0 micromol/l; p < 0.001) were found. API was poor (CD 85.4 +/- 23.6, Con 31.8 +/- 24.1, p < 0.001) and correlated with sucrose intake (p < 0.01). Caries prevalence was increased in patients with longer disease (>3 years) (DMFT index: >3 years 15.6 +/- 5.7 vs. <3 years 9.5 +/- 4.3; p < 0.05). CONCLUSION: Dental status in CD patients is poor. Both increased sugar consumption and insufficient oral hygiene seem to cause the higher caries prevalence. Obviously, patients with CD belong to a high-risk group, and preventive measures should be taken early in the course of the disease.

Adult↗
PubMed1990

Incidence of P.T.C. taste sensitivity and threshold in Kashmiri population.

Taste sensitivity and threshold of Phenylthiourea (PTC) was determined in 800 individuals of Kashmir who form a distinct ethnic group. Correlation, if any, with age, sex, blood group, pH of Saliva, or smoking habits was investigated. The taste sensitivity of P.T.C. increased with advancing age. The percentage of non-tasters was more in blood group 'B' & 'O'. However, no correlation was observed as far as sex, pH of saliva and smoking habits were concerned.

Adolescent↗
PubMed1976

[Relations between structure and bitter taste of amino acids and peptides. II. Peptides and their derivatives (author's transl)].

About 80 peptides and their derivatives were tested for bitter taste. The taste thresholds are in the range of 70-80 muMol/ml (Gly-Val) to 0.01-0.02 muMol/ml (Bacitracin). They are dependent on nature and number of the side chains and on the hydrophobicity of the whole molecule. An estimation of the taste thresholds of all di-and tripeptides with known amino acid composition is possible on the basis of their hydrophobicity. As could be shown recently for bitter amino acids, a polar (electrophilic) and a hydrophobic group are essential requirements for bitter peptides also. This model corresponds to all sensory results, e.g. to the bitter taste of all hydrophobic peptides independent on their sequence and configuration and to the sweet taste of L-aspartyl dipeptide esters.

Amino Acids↗
PubMed1997

Depressive symptoms and alterations in sucrose taste perception: cognitive bias or a true change in sensitivity?

Previous studies have reported elevated taste thresholds in depressed subjects, but those studies did not control for changes in response bias. The current study used signal detection analyses to address this shortcoming. Sucrose detection thresholds were measured (1) in subjects with high and low Hamilton Depression Rating Scale (HAM-D) scores who did not meet standard criteria for current Major Depressive Episode (MDE); and (2) in subjects who did fulfil standard criteria for MDE. Subjects with low HAM-D scores produced significantly more false alarms than the other two groups, but taste sensitivity, as indexed by d', did not vary significantly across groups. These results suggest that changes in response bias underlie previously reported increases in sucrose taste thresholds in depressed subjects.

Adult↗
PubMedDate not supplied

The effects of diabetes and autonomic neuropathy on parotid salivary flow in man.

Stimulated parotid salivary flow studies were performed on 20 non-diabetic subjects and on 30 patients with insulin-dependent diabetes mellitus who had been screened for autonomic neuropathy using tests of cardiovascular reflexes. Electrical gustometry was performed to detect the taste threshold. The stimulated parotid salivary flow rates of diabetics with no autonomic neuropathy or early parasympathetic autonomic dysfunction alone were similar to those of non-diabetic subjects. Diabetic patients with established parasympathetic autonomic neuropathy had significantly higher salivary flow rates as did those with combined sympathetic and parasympathetic neuropathies. Taste thresholds did not correlate either with the duration of the diabetes or with the presence of autonomic neuropathy. The cause of the increased salivary flow associated with diabetic autonomic neuropathy is unclear. It may represent the removal of a neural inhibitory mechanism which modulates salivary flow, or the effects of long-standing diabetes on salivary secretion.

Adult↗
PubMed1984

Taste acuity and zinc status in chronic renal disease.

The malnutrition often associated with progressive renal failure may be related to a progressive deterioration of taste acuity. To determine the relationships between taste acuity, zinc status, and progressive renal failure, 27 subjects were divided into three groups and classified as having mild, moderate, or severe renal failure, with creatinine clearance of 41 to 75, 15 to 40, and 5 to 14 ml/minute, respectively. The subjects were evaluated for recognition taste thresholds for sour and sweet by the Cornsweet method. Serum, urinary, and salivary levels for zinc were determined by atomic absorption techniques. Food diaries were kept for two days; intakes of protein and zinc were calculated from the diaries. There was a significant (p less than .01) inverse relationship between creatinine clearance and recognition taste thresholds for sour and sweet. Serum zinc levels were significantly lower (p less than .01) for subjects with severe renal failure than for subjects with mild renal failure. The subjects who ingested more protein also ingested more zinc.

Adolescent↗
PubMed1977

Phenylthiocarbamide (PTC) taste sensitivity in selected populations of the Isle of Man and Cumbria.

PTC taste thresholds were determined using a modification of the Harris and Kalmus sorting technique for 854 Cumbrian schoolchildren and 699 individuals from the Isle of Man. A non-taster frequency of 19.7 percent was observed in the Cumbrian sample compared with a frequency of 27.8 per cent in that from the Isle of Man. Analysis of taste threshold distributions revealed significant variability, both within and between these two samples. Evidence of significant regional heterogeneity was detected in Cumbria but not in the Isle of Man. Finally, these two series were compared with data from neighbouring regions of the British Isles and Scandinavian populations.

Adolescent↗