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PubMed2002

[Gustatory disturbance associated with putaminal hemorrhage].

48-year-old left-handed man experienced a sudden loss of taste, followed by dysarthria and dysphagia. Taste threshold examined by a small filter-paper disc method was severely elevated on both sides of the tongue. Brain CT revealed right putaminal hemorrhage that measured 9.3 ml in volume. In addition, brain MRI showed multiple cerebral infarcts bilaterally in the basal ganglia, and the corona radiata, and on the right side of the middle pontine tegmentum. His dysarthria and dysphagia seemed to be caused by interruption of bilateral cortico-bulbar tracts, and resolved within two weeks when edema around the hemorrhage regressed. The gustatory disturbance that persisted may be caused by the interruption of central gustatory pathways at the pons on one side, and subcortically close to the insular cortex on the other side.

Cerebral Infarction↗
PubMed2001

Characterization of natural "cooling" compounds formed from glucose and l-proline in dark malt by application of taste dilution analysis.

Gel permeation chromatography of the solvent extractables isolated from a thermally treated glucose/L-proline mixture and sensory analysis of the fractions collected led to the discovery of the presence of "cooling" compounds in Maillard reactions. To characterize the key compounds imparting this cooling sensation to the oral cavity, a taste dilution analysis was performed by determining the taste threshold of reaction products in serial dilutions of HPLC fractions to select the most intense "cooling" compounds in the complex GPC fraction of the Maillard reaction mixture. Systematic (13)C-labeling experiments and GC-MS, LC-MS, and 1D- and 2D-NMR measurements, followed by synthesis, led to the unequivocal identification of 3-methyl-2-(1-pyrrolidinyl)-2-cyclopenten-1-one (3-MPC), 5-methyl-2-(1-pyrrolidinyl)-2-cyclopenten-1-one (5-MPC), and 2,5-dimethyl-4-(1-pyrrolidinyl)-3(2H)-furanone (DMPF) as the key compounds contributing the most to the cooling sensation. Although these structures were described earlier with regard to Maillard reactions, this is the first time that Maillard reaction products are reported to cause intense cooling sensations by degustation. Finally, the detection of 5-MPC (101.3 microg/kg), 3-MPC (9.4 microg/kg), and DMPF (11.5 microg/kg) in dark malt verified their natural occurrence in thermally processed foods.

Chromatography, Gas↗
PubMed1969

An electrophysiological analysis of the action of carbohydrates on the sugar receptor of the blowfly.

Measurements of the taste thresholds of blowflies for a wide variety of carbohydrates, presented individually and in combination, showed that the stimulating effects of the compounds are not always additive. Both synergism and inhibition were observed. In order to gain some insight into the nature of the molecular events occurring in the receptor, it was deemed necessary to investigate synergism and inhibition in single receptors by electrophysiological methods. This investigation revealed that mannose enhances the responses of the sugar receptor of the blowfly to aldose and aldose-derived sugars and reduces responses to the ketose sugars. Responses to fructose are enhanced by the presence of glucose and reduced by the addition of sorbose. Curves describing responses to the aldose and aldose-derived sugars over a wide range of concentrations have steep slopes and intersect the x axis at high concentration values. Curves relating to the ketoses have shallow slopes and lower intercepts. Two or more modes of action of carbohydrates on the sugar receptor are suggested by these data.

Animals↗
PubMed1993

Color as a factor in food choice.

From birth, nature teaches us to make judgements on our environment based in large measure on color. As such, it plays a key role in food choice by influencing taste thresholds, sweetness perception, food preference, pleasantness, and acceptability. Its role is elusive and difficult to quantify, however, which at times has placed color in a secondary role to the other sensory characteristics, a position not entirely consistent with the facts. Color, in a quantitative sense, has been shown to be able to replace sugar and still maintain sweetness perception in flavored foods. It interferes with judgments of flavor intensity and identification and in so doing has been shown to dramatically influence the pleasantness and acceptability of foods. Studies in the literature have used cross-sectional population panels to study these effects, but a recent investigation of color-sensory interactions in beverages has compared the response of a college age group with the response of a panel consisting of a more mature population. Interestingly, the older group showed significant differences from the college age group in their response to the effects of color on several sensory parameters as well as showing a direct correlation between beverage consumption and color. Color is often taken for granted, but this position must be reevaluated in view of such studies and the need to create more appealing foods for different segments of our society.

Carbohydrates↗
PubMed1982

Population genetic models in the study of aging and longevity in a Mennonite community.

This is a preliminary report on a 3-year multidisciplinary study of aging among historically and genetically related Mennonite congregations in Kansas and Nebraska. Three aspects of longevity and aging are examined: (1) the relationship of heterozygosity to survivorship using 8 genetic blood group loci, (2) changes in taste sensitivity with age using 14 dilutions of PTC; and (3) life span correlations among parents and offspring during a 100 year period. Heterozygosity was found to be independent of survivorship. No diminution in taste sensitivity to PTC was found with increasing age although a significant difference in PTC taste thresholds was found between males and females. No relationship was found between nontasters and individuals with a history of thyroid disease. Mother's life span was found to correlate more closely with daughter than any other familial correlation.

Adolescent↗
PubMed2005

Determination of trace concentrations of bromophenols in water using purge-and-trap after in situ acetylation.

An analytical method that enables detection and quantification of bromophenols (BPs) at taste threshold concentrations (2,6-DBP: 0.5 ng/L) was developed. This method involves conversion of the BPs to their acetates, followed by isolation of the acetates by a modified purge-and-trap procedure, and analysis by gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. Bromophenyl acetates were synthesized so that each of the two steps in the method could be developed and optimised in isolation to the other. Deuterated BPs (phenol-d5, 2-BP-d4, 4-BP-d2, 2,6-DBP-d3, 2,4-DBP-d3 and 2,4,6-TBP-d2) were synthesized to enable quantification of analytes using the deuterated analogues of analytes as internal standards. This method allowed quantification of BPs at concentrations ranging from the detection limits (3 ng/L for phenol and 0.1-0.5 ng/L for each of the BPs) to 1000 ng/L for each analyte, with repeatabilities of < or =14% (RSD) for concentrations of 1 ng/L and < or =9% (RSD) for concentrations of 10-1000 ng/L, with recoveries ranging from 91 to 97%.

Acetylation↗
PubMed2005

Identification of metallic-smelling 1-octen-3-one and 1-nonen-3-one from solutions of ferrous sulfate.

Taste threshold tests of ferrous sulfate (FeSO4) solutions have been confounded by the presence of putative odorants. To detect the presence of odorants released from these solutions solid-phase microextraction (SPME) was used to collect volatiles in the headspace above FeSO4 solutions. Gas chromatography-olfactometry of samples collected over three time periods (1, 5, and 16 h) and at two temperatures (22 and 37 degrees C) revealed the presence of several metallic-smelling odorants in the headspace. Using authentic standards, two of the odorants were conclusively identified as 1-octen-3-one and 1-nonen-3-one. Trace levels of other odorants were also detected, but dilution experiments indicated that 1-nonen-3-one was at least 10 times more potent than anything else released from the solutions. 1-Octen-3-one and 1-nonen-3-one are excellent candidates for the metallic odor responses often observed in threshold testing of solutions of FeSO4.

Chromatography, Gas↗
PubMed1999

A kinetic study on benzoic acid pungency and sensory attributes of benzoic acid.

Aqueous solutions of benzoic acid (BA) were evaluated by two methods: (i) sensory profile: a descriptive test of sensory attributes combined with semiquantitative analysis; and (ii) pungency intensity measures as a function of time: a computerized recording using specific software. Kinetic parameters evaluated were maximal intensity (I(MAX)), total time of pungency (Ttot), rates of increase (V1) and decrease (V2), half-life (T1/2), area under curve (AUC) and time to maximal intensity (T(IMAX)). Results were analyzed by ANOVA, LSD test, iterative calculations and adjustment to equations according to mathematical models, regression analysis, principal component analysis (PCA) and clusters analysis. Pungency was the main sensory attribute of BA (3-36 mM) in the tongue and epiglottis. The seven kinetic parameters showed concentration-dependency (P < 0.001) and were described by different functions: (i) lineal: I(MAX) = 2.24 +/- 0.14C - 3.06 +/- 2.58, R2 = 0.98; T(IMAX) = 0.19 +/- 0.02C + 6.87 +/- 0.47, R2 = 0.92; V1 = 0.68 +/- 0.03C + 0.10 +/- 0.69, R2 = 0.99; AUC = 49.10 +/- 3.17C - 230.78 +/- 59.66, R2 = 0.98; (ii) potency: T1/2 = 6.62 +/- 0.61C(0.39+/-0.03), R2 = 0.97; V2 = 1.07 +/- 0.11C(0.53+/-0.04), R2 = 0.98; Ttot = 8.08 +/- 1.01C(0.43+/-0.04), R2 = 0.96. PCA revealed high correlation between (i) T(IMAX) and Ttot; (ii) T1/2 and V2; and (iii) I(MAX) and V1. Stimuli grouped across three main clusters: (i) 3 and 6 mM; (ii) 9, 12 and 18 mM; and (iii) 24 and 36 mM. Maximal pungency intensity best correlated with both concentration and persistence among kinetic parameters. Prototypical prickling of BA was observed at 12 and 18 mM.

Adult↗
PubMed1986

Design and analysis considerations for a longitudinal study of periodontal disease.

Perception and concern for the health changes in our aging population led the Veterans Administration to initiate an interdisciplinary and longitudinal investigation of the aging process, the Veterans Administration Normative Aging Study, in 1963. A cohort of the 2,280 healthy men of this study self-selected to enroll in the dental longitudinal study, an investigation of oral health in these healthy males. In 1968, 1,221 men between the ages of 25 and 75 began with a baseline cycle of 5 general series of examinations, including an interim health history and survey of dietary habits; masticatory performance and taste thresholds; salivary analyses; oral cytologic and radiographic survey and comprehensive clinical data on caries and periodontal status. Design considerations for the Dental Longitudinal Study included prospective planning of specific oral variables to be recorded, and provision of collection techniques to allow for additional analyses based on a wide menu of retrospective data. The volunteer cohort was screened to obtain men who met stringent general health criteria, who represented wide socioeconomic ranges and would likely remain geographically stable. Importantly, enrollment in the parent study was without regard for dental status or oral health. Administrative design considerations included orderly transfer for exam data to machine-readable format by use of optical scan forms designed to register specific oral variables, with security preserved for the primary source records and rapid record retrieval. Additional data collection requiring manual coding was designed to transfer spreadsheets of clinical impressions and diagnoses to computer retrieval protocols. Provisions for recording of exceptional circumstances, i.e., salient oral pathology, were recognized and the optical scan forms modified to index and retrieve such cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2003

Positional cloning of the human quantitative trait locus underlying taste sensitivity to phenylthiocarbamide.

The ability to taste the substance phenylthiocarbamide (PTC) has been widely used for genetic and anthropological studies, but genetic studies have produced conflicting results and demonstrated complex inheritance for this trait. We have identified a small region on chromosome 7q that shows strong linkage disequilibrium between single-nucleotide polymorphism (SNP) markers and PTC taste sensitivity in unrelated subjects. This region contains a single gene that encodes a member of the TAS2R bitter taste receptor family. We identified three coding SNPs giving rise to five haplotypes in this gene worldwide. These haplotypes completely explain the bimodal distribution of PTC taste sensitivity, thus accounting for the inheritance of the classically defined taste insensitivity and for 55 to 85% of the variance in PTC sensitivity. Distinct phenotypes were associated with specific haplotypes, which demonstrates that this gene has a direct influence on PTC taste sensitivity and that sequence variants at different sites interact with each other within the encoded gene product.

Alleles↗
PubMed1991

Chromosomal Integration and Expression of Two Bacterial alpha-Acetolactate Decarboxylase Genes in Brewer's Yeast.

A bacterial gene encoding alpha-acetolactate decarboxylase, isolated from Klebsiella terrigena or Enterobacter aerogenes, was expressed in brewer's yeast. The genes were expressed under either the yeast phosphoglycerokinase (PGK1) or the alcohol dehydrogenase (ADH1) promoter and were integrated by gene replacement by using cotransformation into the PGK1 or ADH1 locus, respectively, of a brewer's yeast. The expression level of the alpha-acetolactate decarboxylase gene of the PGK1 integrant strains was higher than that of the ADH1 integrants. Under pilot-scale brewing conditions, the alpha-acetolactate decarboxylase activity of the PGK1 integrant strains was sufficient to reduce the formation of diacetyl below the taste threshold value, and no lagering was needed. The brewing properties of the recombinant yeast strains were otherwise unaltered, and the quality (most importantly, the flavor) of the trial beers produced was as good as that of the control beer.

Journal Article↗
PubMed1984

Salivary clearance of sugar and its effects on pH changes by Streptococcus mitior in an artificial mouth.

We recently developed a computer model of oral sugar clearance (Dawes, 1983), and an artificial mouth has now been constructed which will allow variation in the salivary parameters identified in the model and the study of their effects on bacterial acid production. Using a thin layer of S. mitior, strain 572, over a miniature Sb electrode to measure bacterial pH changes during sugar clearance from the "mouth", we found that three consecutive sets of "Stephan curves" could be obtained with the same bacteria during one day. In each of several experimental series, one salivary parameter was varied, while other parameters were held constant. The maximum pH decrease and the surface area of the registered Stephan curve (delta pH.min) were used as measures of acid production. The results indicate that the volume of "saliva" in the mouth before and after swallowing, the unstimulated salivary flow rate, and the buffer capacity had significant influences on the extent of the pH changes. Other factors, such as the maximum flow rate, the delay between start of stimulation and maximum flow, the volume of saliva in the mouth at time zero, and the taste threshold for sugar, were of lesser importance, confirming some predictions from the computer model.

Buffers↗
PubMed2005

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.

Adult↗
PubMed1981

The relative importance of genetic and environmental factors in hypertension in black subjects.

Essential hypertension is the most important cardiovascular disease in black subjects. The types of presentation, the pattern of organ involvement and the subsequent complications are similar in black races. The response (or lack of response) to different types of treatment are also alike in blacks when compared with caucasians. Striking racial differences are observed in the plasma and intracellular electrolytes, cation transmembrane transport, salt taste threshold, plasma renin activity and urinary kallikrein activity. The similarities within the black racial groups are very likely to be genetic, although the pattern of inheritance remains controversial. Differences, however, occur in the prevalence and severity of the disease among the black racial groups. That these differences are due partly to environmental causes can not be disputed because even within the same ethnic groups changing patterns are observed in the prevalence of hypertension, in the course of urbanization of rural communities, or on moving from a previously rural to an urban environment. Consequently, genetic factors may be the only important considerations in the severity of hypertension in black subjects.

Adrenergic beta-Antagonists↗
PubMed1993

Hypertension in Africa and effectiveness of its management with various classes of antihypertensive drugs and in different socio-economic and cultural environments.

Hypertension is the commonest cardiovascular disease in Africans occurring in more than 15% of the adult population in some studies. It occurs in the lower as much as in the higher socio-economic groups. Recent studies have confirmed earlier findings that essential hypertension in Africans is characterised by volume loading, low plasma renin activity, high salt taste threshold, high urinary sodium and low potassium excretion and high plasma aldosterone. The commonest complication of hypertension in Africans is congestive cardiac failure followed by cerebrovascular accidents. Coronary heart disease is rare. Even in the absence of overt heart failure and compounding factors like obesity, alcoholism, cigarette smoking, diabetes mellitus and myocarditis, evidence of abnormal left ventricular morphology and function is often present in newly diagnosed patients with moderate or severe hypertension. Response to monotherapy with beta-blockers or ACE inhibitors is usually poor but is good with thiazide diuretics or calcium channel blockers. The diuretics are an essential component of a two or three drug regime containing other classes of antihypertensive drugs. Cost of drugs is the most important determinant of compliance with drug treatment and consequently the likelihood of progression of the diseases to more severe forms in long term follow-up.

Africa↗
PubMed2005

[Olfactory and gustatory disorders--causes, diagnosis and treatment].

Olfactory and gustatory disorders are by no means uncommon, and may be associated with an appreciable impairment of the patient's quality of life. In many cases, diagnosis and treatment is not easy, and necessitates interdisciplinary cooperation between the general practitioner, internist, ENT specialist, neurologist and psychiatrist. Many of the non-evidence-based treatments still applied in hospitals and the physician's office should, for reasons of quality control and to avoid polypragmasy possibly associated with undesirable side effects, be employed with reservations. With reference to the guidelines issued by the working group Olfactologie/Gustologie der Deutschen Gesellschaft für HNO-Heilkunde, Kopf- und Hals-Chirurgie (Olfactology/Gustology of the German Society of ENT Medicine, Head and Neck Surgery), a review of the causes, diagnosis and treatment of olfactory and gustatory disorders [3,4] is presented.

Ageusia↗
PubMed1989

[Interaction between food texture and dental health].

The consistency is one of the sensoric properties of a food item and forms the origin of texture. The texture of a food item can be distinguished in hardness, toughness, stickiness, juiciness and chewability. The consistency of food items may influence dental health. It is suggested that hard food cleans the teeth. The chewing pattern depends on the texture of the masticated food. Hard and tough food require a more horizontal movement of the lower jaw, contrary to soft and tender food which mainly require a vertical movement. An adequate food texture contributes to the acceptability and the preference of food.

Food↗
PubMed1988

[Effect of the incorporation of additives on the aging of corn starch gels and "arepas"].

This research was carried out to investigate the effect of the incorporation of various additives on the ageing of corn starch and arepas. Starches were extracted from the endosperm of degerminated corn by a wet milling process, and its retrogradation, with or without the incorporation of additives was evaluated using the Brabender amilograph and by measuring the viscosity changes of the starch gels through time, using a Brookfield viscometer model RVT. The most effective additives in retarding the rate of ageing of starch gels, were used in the arepas. Likewise, trained panelists were utilized to find the levels of the additives incorporated in the arepas, by running taste threshold tests for each one of the additives. Textural changes of the arepas--maintained at two different storage temperatures, 9 degrees and 23 degrees C--were evaluated using an Instron texturometer. Preliminary tests with the corn starch allowed to choose the following additives: distilled monoglicerides, guar gum and hydrogenated vegetable oil. The effect of 15 different combinations of these additives on the texture of arepas was then studied, and findings revealed that only three of them were able to totally revert the retrogradation process, and maintain the hardness and elasticity within the expected range of a fresh-made arepa, when this is reheated until reaching a maximum temperature of 49 degrees C. A 66% of the hardening of the arepas prepared without additives can be reverted with the reheating process, but only if the product has not suffered dehydration. When stored for 24 hours at room temperature, unpacked arepas have a surface moisture loss of 47%, and even if reheated, hardening becomes irreversible in 84.6% of them.

Food Additives↗