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PubMed1978

[Current knowledge on the organoleptic characteristics of beer].

This important subject will be considered in three parts: I. Tasting procedures. As there is no standard nomenclature in brewing for describing the organoleptic properties, each brewery has devised its own terminology for this purpose. Four organizations: the European Brewery Convention (EBC), the American Society of Brewing Chemists (ASBC), the Master Brewers Association of America (MBAA) and the Institute of Brewing have collaborated to produce a standard terminology for beer tasting suitable for international use. Different tasting procedures, as well as their statistical interpretation will be discussed. II. Threshold values of certain compounds. Several hundred compounds present in beer have been studied and their threshold values are known for certain types of beer. Particular methods of tasting have been tried out to determine precisely the threshold value of a pure compound in beer. III. Correlation between the tasting results and the physico-chemical properties of beer. The application of statistical methods of analysis to the testing results and physico-chemical properties of different beers has allowed the importance of certain constituants of these beers to be estimated.

Beer↗
PubMed2002

Electrophysiological studies of salty taste modification by organic acids in the labellar taste cell of the blowfly.

Using the labellar salt receptor cells of the blowfly, Phormia regina, we electrophysiologically showed that the response to NaCl and KCl aqueous solutions was enhanced and depressed by acetic, succinic and citric acids. The organic acid concentrations at which the most enhanced salt response (MESR) was obtained were found to be different: 0.05-1 mM citric acid, 0.5-2 mM succinic acid and 5-50 mM acetic acid. Moreover, the degree of the salt response was not always dependent on the pH values of the stimulating solutions. The salt response was also enhanced by HCl (pH 3.5-3.0) only when the NaCl concentration was greater than the threshold, indicating that the salty taste would be enhanced by the comparatively lower concentrations of hydrogen ions. Another explanation for the enhancement is that the salty taste may also be enhanced by undissociated molecules of the organic acids, because the MESRs were obtained at the pH values lower than the pKa(1) or pKa(2) values of these organic acids. On the other hand, the salty taste could be depressed by both the lower pH range (pH 2.5-2.0) and the dissociated organic anions from organic acid molecules with at least two carboxyl groups.

Animals↗
PubMed2000

Genetic taste markers and preferences for vegetables and fruit of female breast care patients.

OBJECTIVE: To explore links between genetic responsiveness to the bitter taste of 6-n-propylthiouracil (PROP) and self-reported preferences for vegetables and fruit of female breast care patients. METHODS: PROP tasting was defined by detection thresholds and by perceived bitterness and hedonic ratings for PROP solutions. Nontasters, medium tasters, and supertasters were identified by their PROP thresholds and by the ratio of perceived bitterness of PROP to the perceived saltiness of sodium chloride solutions. Subjects rated preferences for vegetables and fruit using 9-point category scales. SUBJECTS/SETTING: A clinical sample of 170 patients with newly diagnosed breast cancer and 156 cancer-free control subjects were recruited from the University of Michigan Breast Care Center. STATISTICAL ANALYSES: Principal components factor analysis, one-way analyses of variance, and Pearson correlations and chi 2 tests were used to analyze taste and food preference data. RESULTS: Genetic responsiveness to PROP was associated with lower acceptance of cruciferous and selected green and raw vegetables (P < .05). Women who reported disliking such foods were medium tasters or supertasters of PROP. Preference ratings for fruit were unrelated to PROP taster status. APPLICATIONS/CONCLUSIONS: Women who are PROP tasters may be less likely to comply with dietary strategies for cancer prevention that emphasize consumption of cruciferous vegetables and bitter salad greens. Alternatively, PROP-sensitive women may seek to reduce bitter taste by adding fat, sugar, or salt.

Breast Neoplasms↗
PubMed1977

Taste acuity of the human palate. I. Studies with electrogustometry and taste solutions on young adults.

The purposes of the study were to determine whether or not taste perception was present in the area which would have been covered by the base plate of a full upper denture and, if taste perception was present there, to compare its strength to that of the remainder of the soft palate and of the apex and base of the tongue. The taste acuity of 32 dental students was measured at the apex and base of the tongue and on the hard and soft palate using two methods, an electric current and sweet, salty, sour and bitter test solutions, the latter in order to determine whether or not there exist differences in the perception of the different taste modalities in these areas. No taste perception could be demonstrated on the hard palate except in the region close to the border between the hard and soft palate, where the threshold values were very high compared with those for the soft palate immediately behind this border and for the tongue. The inter-individual range of the threshold values for the soft palate was very large. Further studies on the taste acuity of the human palate and its role in the total perception of taste are indicated.

Adult↗
PubMedDate not supplied

[The chemical senses of smell and taste in the course of life - changes of smell and taste perception].

Based on own experiments and on the results of other laboratories changes of olfactory and gustatory perception throughout the life span are discussed. Similar to other modalities gustatory and olfactory thresholds generally rise while age increases. Certain gustatory substances (amino acids), however, show a decrease of thresholds if 70 years old subjects are compared with 20 years old ones. Preference for certain odorants (strawberry, vanillin) are reported to increase in higher age (after initial higher peaks in young age).

Adolescent↗
PubMed2006

Use of multiple headspace solid-phase microextraction and pervaporation for the determination of off-flavours in wine.

The occurrence of off-flavours in wines and especially the so-called "cork taint defect" represents one of the most serious problem in wine industry in which 2,4,6-trichloroanisole has been blamed as the main responsible. The development of analytical methods for haloanisoles determination in wine/cork represent a challenge, mainly due to food matrix complexity and low taste and odour (T&O) threshold levels which are generally beyond the sensitivity of the analytical systems. In this work, a method based on the combined use of the recently developed multiple headspace solid-phase microextraction (MHS-SPME) and gas chromatography-ion-trap mass spectrometry has been optimised for the determination of haloanisoles in wines. This powerful analytical methodology is compared with several analytical approaches based on pervaporation, an innovative membrane-based technique similar to dynamic headspace. Analytical features of the methods assayed reveal their suitability for the appraisal of haloanisoles in this matrix in which threshold odor concentrations are in the range 4-40 ng l(-1). The analytical approaches have been applied to the analysis of haloanisoles in different Spanish white and red wines, in which spiking experiments showed good recoveries for the methodologies assayed.

Anisoles↗
PubMed2000

Taste effects of lingual application of cardiovascular medications.

Medications used to treat cardiovascular diseases such as congestive heart failure, high blood pressure, and arrhythmia, are prescribed extensively in Western countries. However, taste complaints are common side effects of many of these cardiovascular medications. Although clinical observations are helpful in determining potential taste problems from a medication, experimental studies are necessary to obtain quantitative data on taste. In the studies performed here, nine cardiovascular medications (labetalol HCl, captopril, diltiazem HCl, enalapril maleate, hydrochlorothiazide, propranolol HCl, mexiletine HCl, procainamide HCl, and propafenone HCl) were applied to the tongue in human volunteers to measure the direct effect of these drugs on taste receptors. The medications were applied topically to the tongue surface of both young and elderly subjects to mimic the situation in which the drug is secreted into the saliva. Detection thresholds ranged from 0.048 mM (propafenone) to 0.438 mM (procainamide). The detection thresholds of healthy elderly subjects did not significantly differ from young controls. The compounds tested had a predominantly bitter taste with other qualities as well. In addition, topical application of the medications to the tongue affected the taste of one or more taste stimuli, with medications differing in the pattern of taste effects exhibited. The mechanism of taste effects is not fully known, but the results of this study suggest one route may be due to medications' effect on peripheral taste receptors.

Administration, Sublingual↗
PubMed2000

Assessment of gustatory function by means of tasting tablets.

OBJECTIVE: To develop a simple test for the screening of gustatory function in clinical settings. STUDY DESIGN: We tested 101 healthy volunteers (44 male and 57 female volunteers; mean age, 47 y) with the following gustatory test: the substances sucrose (sweet), citric acid (sour), sodium chloride (salty), and caffeine (bitter) were presented as tablets (diameter 4 mm) similar to common sweetener tablets. For quantitative assessment of whole-mouth gustatory function we used six different dosages with dilutions of each tastant in 50% steps. The highest dosage could be easily detected (sucrose, 30 mg; citric acid, 3 mg; sodium chloride, 2 mg; caffeine, 2 mg), and the lowest concentration was within threshold range. METHODS: Twenty-eight tablets (six different dosages of the four basic tastes plus four tasteless tablets) were tried in a randomized order. The entire test required 15 to 20 minutes. To evaluate the within-subject test-retest reliability, sessions were repeated after 1 week. Results were compared with those obtained by means of a conventional three-drop, forced-choice procedure using the method of ascending limits. RESULTS: Results of the new gustatory test were significantly correlated with those obtained using the three-drop, forced-choice procedure (correlation coefficient [r] = 0.66, P<.001). In general, women performed better than men. Furthermore, younger subjects exhibited a significantly higher gustatory sensitivity in both tests compared with older subjects. CONCLUSIONS: This quantitative test of whole-mouth gustatory function is easy to use, can be self-administered, requires little time, and has a long shelf-life. It appears to be suited for routine clinical assessment of gustatory function.

Adult↗
PubMed1997

Menstrual phase, history of smoking, and taste discrimination in young women.

University women who were either nonsmokers or who had smoked regularly for at least two years (ns = 7) attempted to discriminate a gustatory stimulus five days before and five days after their menses. The stimuli were presented 3 min. or 5 min after the introduction of a target stimulus. A statistically significant interaction was found among history of smoking, menstrual phase, and latency for taste comparisons. However, when the shared variance between olfactory and gustatory accuracy was partialled out, the results for smokers suggested significant increases in gustatory thresholds relative to those of nonsmokers regardless of menstrual phase. Smokers also displayed significantly less (eta 2 = 25%) accuracy for olfactory discrimination than nonsmokers.

Adult↗
PubMed2000

Testing taste sensitivity and aversion in very young children: development of a procedure.

Taste perception in 45 3- to 6-year-old children was tested using procedures specifically designed for this age group. Detection thresholds for sucrose and urea were measured by a staircase method and aversion to urea was assessed hedonically, using drawings of facial expressions. All children understood the task and could perform the necessary actions. A subgroup of 20 children participated in a second measurement after a mean interval of 9.5 days: there was a satisfactory degree of stability between the sessions. However, a third measurement, on a subgroup of 13 children after a somewhat longer interval, showed a marked drop in the stability of the urea thresholds. This drop was thought to arise from a decrease in the children's motivation, leading to increased distractibility. Mean threshold estimates were 31 mmol/l for sucrose detection, 59 mmol/l for urea detection and 134 mmol/l for urea aversion, but some children were extremely sensitive to the taste of urea. The findings show that it is possible to study taste perception in very young children if their age is taken into consideration in developing the test procedure. Valid data can be obtained if the procedures are short, easy to understand and intrinsically motivating.

Child↗
PubMed1979

The metabolic effects of sodium depletion in calves on salt appetite assessed by operant methods.

1. Sodium deficiency was induced in calves by unilateral exteriorization of the parotid duct, the continual loss of alkaline saliva from the body to the environment causing negative sodium balance. 2. The metabolic effect of negative sodium balance was seen in statistically significant reduction in plasma sodium and blood bicarbonate, together with marked acidosis and reduced plasma osmolality. 3. The homoeostatic response to sodium depletion was associated with a reversal of sodium/potassium ratio in parotid saliva and a reduction of the rate of secretion. Appetite diminished. The extracellular fluid was halved as marked diuresis developed with considerable weight loss. Urinary and faecal sodium was reduced to zero. 4. On restoration of sodium balance by allowing the calves to drink sodium bicarbonate solutions the metabolic deviations were eliminated. 5. During sodium depletion the parotid gland was able to respond to transient reflex stimulation by increasing flow rate and the sodium concentration of the saliva. 6. When sodium depleted, the calves became restless and agitated and would run from the home pen to the operant procedure stand. The sodium depleted animals readily pressed a panel for sodium bicarbonate rewards in direct proportion to the degree of sodium imbalance. When the balance was restored the motivation to work for sodium bicarbonate disappeared. 7. The motivation which developed during sodium depletion was directed specifically towards the sodium ion. Lithium was an exception to this rule and sodium carbonate was aversive. 8. It is possible that in sodium depletion the glottal sodium taste receptors develop an enhanced threshold for sodium ions because of the reduced sodium content of the saliva. This effect would be abolished when the content of sodium was restored in saliva. 9. The correlation of operant reactions and sodium depletion suggests that the consequential metabolic effects activate changes in the central nervous system. 10. The metabolic changes which develop in parallel with the severity of the sodium deficit appear to be able to evoke behavioural changes with increase in salt appetite directed towards restoration of sodium balance.

Animals↗
PubMed2005

Structure-sweetness relationship in egg white lysozyme: role of lysine and arginine residues on the elicitation of lysozyme sweetness.

Lysozyme is one of the sweet-tasting proteins. To clarify the structure-sweetness relationship and the basicity-sweetness relationship in lysozyme, we have generated lysozyme mutants with Pichia systems. Alanine substitution of lysine residues demonstrated that two out of six lysine residues, Lys13 and Lys96, are required for lysozyme sweetness, while the remaining four lysine residues do not play a significant role in the perception of sweetness. Arginine substitution of lysine residues revealed that the basicity, but not the shape, of the side chain plays a significant role in sweetness. Single alanine substitutions of arginine residues showed that three arginine residues, Arg14, Arg21, and Arg73, play significant roles in lysozyme sweetness, whereas Arg45, Arg68, Arg125 and chemical modification by 1,2-cyclohexanedione did not affect sweetness. From investigation of the charge-specific mutations, we found that the basicity of a broad surface region formed by five positively charged residues, Lys13, Lys96, Arg14, Arg21, and Arg73, is required for lysozyme sweetness. Differences in the threshold values among sweet-tasting proteins might be caused by the broadness and/or the density of charged residues on the protein surface.

Amino Acid Substitution↗
PubMed1989

[Taste in healthy subjects. Influence of alcohol and tobacco consumption].

To define the factors which may affect gustatory function, 42 healthy subjects, without any apparent taste disorder were randomly selected and investigated by electro-gustometry and chemical gustometry. A deterioration in taste discrimination was noted in drinkers in comparison with non-drinkers, both on electro-gustometry, mean threshold (SEM: 88.0 +/- 26.5 versus 47.4 +/- 7.3 microA; p less than 0.05), and also on chemical gustometry (15.1 +/- 2.1 versus 17.4 +/- 0.7; p = 0.05) and also in smokers compared with non smokers (mean of electrical thresholds SEM 104.2 +/- 22.8 versus 38.3 +/- 5.2 microA; p less than 0.01, mean of chemical scores SEM 14.3 +/- 1.1 versus 17.9 +/- 0.9; p less than 0.05). Multivariate analysis demonstrated the influence of the two factors alcohol and tobacco on taste, evaluated by electrogustometry (R2 = 0.36) or chemical gustometry (R2 = 0.28). These results suggest that alcohol and tobacco are liable to influence gustatory function in healthy subjects thereby suggesting that this influence should be taken into account using a corrective factor.

Adult↗
PubMed2005

Effects of chemical modification of lysine residues on the sweetness of lysozyme.

Lysozyme is a sweet-tasting protein with a sweetness threshold value of around 7 microM. To clarify the effect of basicity at the side chain of lysine residues on the threshold values of sweetness, charge-specific chemical modifications such as guanidination, acetylation and phosphopyridoxylation of lysine residues were performed. Sensory analysis showed that the sweetness threshold value of lysozyme was not changed by guanidination, whereas it was increased markedly by acetylation and phosphopyridoxylation. To confirm the importance of the basicity in the lysine residues in detail, purification of acetylated (Ac-) and phosphopyridoxylated (PLP-) lysozymes using SP-ion exchange column chromatography was performed. The threshold values were not changed by modification with fewer than two residues (approximately 7 microM), whereas the threshold values significantly increased to 15 and 34 microM when tetra-Ac and tri-PLP, respectively. Furthermore, sweetness was not detected at 30 microM (hexa-, penta-Ac and tetra-PLP). It should be noted that removal of the negative charges of the phosphate groups in the tri-PLP lysozyme by acid phosphatase resulted in the recovery of sweetness (6.4 microM), indicating that basicity at the position of the lysine residues is responsible for lysozyme sweetness and that strict charge complementarities might be required for interaction to its putative receptor.

Acetylation↗
PubMed1985

Rat trigeminal, olfactory and taste responses after capsaicin desensitization.

Experiment 1 showed that capsaicin injections severely reduced or eliminated nasal trigeminal responses to 3 odorants. Experiments 2 and 3 investigated whether desensitized animals could behaviorally detect and discriminate odors. Capsaicin treated animals had no measurable deficits in locating buried food, in odor aversion learning, or in operant odor detection and discrimination. Experiment 4 examined whether behavioral responsiveness to salty, sour and bitter tastes was affected by desensitization. Capsaicin injections did not affect responsiveness to salty or sour, but may have raised rejection thresholds for bitter. Broadly, the present results suggest that substance P-containing fibers mediate trigeminal responsiveness to odorants and irritants but that the loss of this responsiveness does not appreciably affect smell or taste, per se.

Animals↗
PubMed1982

Influence of chirality of amino acids on the growth of perceived taste intensity with concentration.

Amino acids have markedly different taste properties depending upon their chirality and the structure of their side chains. They can modify the taste quality of foods in which they are found naturally or to which they are added depending on their concentrations. In this study, the influence of chirality of amino acids on the growth in perceived taste intensity with concentration was examined. Serial dilutions of 19 D-amino acids were presented to young subjects who indicated the relative intensities of the dilutions using the magnitude estimation procedure. The slopes of the psychophysical functions for 13 of the 19 D-amino acids which related log concentration and log perceived intensity were greater than the slopes for L-amino acids that have been reported in a previous study. The ratio (average slope D-amino acids)/(average slope L-amino acids) was found to be 1.21. The ratio of the slopes for individual enantiomers bears some relationship to taste quality. No conclusive relationships between the slopes of the psychophysical functions were found with chemical structure of thresholds, however. Implications for receptor mechanisms and nutrition are discussed.

Adolescent↗
PubMed1989

Strain differences in amiloride inhibition of NaCl responses in mice, Mus musculus.

The effects of lingual treatment with amiloride, an inhibitor of salt taste responses in several mammalian species, on NaCl responses of the chorda tympani nerve were compared between four inbred strains of mouse (BALB/cCrSlc, DBA/2CrSlc, C57BL/6CrSlc and C3H/HeSlc). In C57BL and C3H mice amiloride significantly suppressed responses of the chorda tympani nerve to NaCl at a concentration 0.1 M or more whereas in BALB and DBA mice the drug did not significantly affect the responses to NaCl at any concentration, suggesting a lack of the amiloride-sensitive receptor component for NaCl in the latter two strains. A two-bottle preference test demonstrated that all strains of mouse usually showed no preference for NaCl at any concentration and avoided NaCl at 0.3 M or more, although some differences were observed in that C57BL and C3H mice showed aversive responses to 0.1 and 0.15 M NaCl, whereas BALB and DBA mice were indifferent to these solutions. The results suggest that there exist prominent differences between mouse strains in the amiloride-sensitive component of their salt receptor systems. However, in mice the taste information derived from the amiloride-sensitive receptor component probably has no remarkable effect on behavioral responses to NaCl except for a possible contribution to decreasing aversion thresholds for NaCl by increasing overall taste information about NaCl.

Amiloride↗