Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “bitterness”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1979

Evidence for neural inhibition in bittersweet taste mixtures.

Three lines of evidence from psychophysical experiments implied that mutual suppression of bitter and sweet tastes is due to neural inhibition rather than chemical interactions in solution or competition of molecules for common receptor sites. Removal of sweetness from bittersweet mixtures caused the bitterness to increase. This was accomplished by adaptation to sucrose or by treatment with Gymnema sylvestre, neither of which affect the concentration of sucrose on the tongue. Such increases in the bitterness of mixtures, independent of the concentration of the sweet masking substance, are difficult to reconcile with suppression by means of chemical interactions. Similar dependence of suppression on perceived intensity (and independence from concentration) was observed with mixtures of phyenylthiocarbamide and sucrose. Tasters of phenylthiocarbamide showed stronger suppression of sweetness than nontasters. This result was also inconsistent with molecular interactions causing suppression, which would have resulted in the same degree of suppression for the two groups. Instead, these findings support neural explanations of mixture suppression, such as antidromic inhibition or occlusion.

Adaptation, Physiological↗
PubMed1978

The analysis of cider phenolics.

Four classes of phenolic compounds may be distinguished in ciders: 1. Phenolic acids; 2. Phloretin derivatives; 3. Catechins; 4. Procyanidins. Only the procyanidins can be classed as true tannins and only they make any contribution to the bitterness and astringency of the product. Traditional methods of tannin analysis, however, fail to estimate the procyanidins as a separate group from the other phenolics. It is now possible to isolate the procyanidin fraction from bittersweet ciders by adsorption onto Sephadex LH-20 and then to separate the individual procyanidins by counter-current distribution between ethyl acetate and water. In this way sufficient material may be obtained to allow structural studies, and we can now show that ciders contain a range of procyanidin polymers probably up to heptameric, based mostly on epicatechin. Tasing panel work on these fractions shows that bitterness is predominantly associated with oligomeric procyanidins and astringency with polymeric procyanidins. Analytical chromatography on Sephadex LH-20 in a water-methanol gradient also shows, for instance, the selective loss of up to 20% of organoleptically significant procyanidins during gelatin fining, and the useful gain in procyanidins which can occur with DDS diffuser extraction. These results are important because a certain amount of bitterness and astringency is considered desirable in blended English ciders, but the true bittersweet apples are in very short supply.

Alcoholic Beverages↗
PubMed2026

CgMYC2 directly activates jasmonate-induced naringin biosynthesis in Citrus grandis 'Tomentosa'.

CgMYC2 links jasmonate signaling to naringin biosynthesis by binding G-box motifs and activating flavonoid-pathway promoters in Citrus grandis 'Tomentosa' Naringin, the predominant bitter-flavanone glycoside in Citrus grandis 'Tomentosa', has well-characterized biosynthetic enzymes, yet the transcriptional regulators coupling hormonal signals to pathway activation remain poorly understood. We demonstrate that CgMYC2, a jasmonate-responsive bHLH transcription factor, functions as a central activator of naringin biosynthesis. Exogenous methyl jasmonate (MeJA) treatment increased naringin content 3.45-fold in seedlings, coinciding with a rapid 6.6-fold induction of CgMYC2 that preceded the peak transcription of five core biosynthetic genes (CgPAL5, CgCHS, CgFNS, Cg7GlcT, and Cg1,2RhaT). Physical interaction between CgMYC2 and the JAZ protein CgJAZ3 was confirmed by pull-down and Co-IP assays, placing CgMYC2 within the canonical jasmonate signaling cascade. Y1H confirmed CgMYC2 binding to the Cg1,2RhaT promoter, EMSA demonstrated direct G-box-dependent binding to all five pathway promoters, and dual-luciferase assays showed transactivation of all five promoters, with the strongest activation for CgCHS. As complementary chromatin-level support, a single-sample CUT&Tag profile revealed G-box-enriched CgMYC2-associated chromatin regions across jasmonate-responsive and secondary-metabolic loci. Virus-induced gene silencing (VIGS) of CgMYC2 reduced naringin content by ~21% and suppressed biosynthetic gene expression, supporting its positive contribution. Furthermore, heterologous overexpression in tomato activated the flavonoid pathway and elevated 16 flavonoid compounds, consistent with evolutionary conservation of the MYC2-G-box regulatory logic. These findings establish CgMYC2 as a central, JA-responsive activator bridging jasmonate perception and naringin biosynthesis, providing a molecular framework for the targeted improvement of bitter-flavonoid traits in citrus.

Citrus↗
PubMed1978

Effects of oral pH on cigarette smoking.

Permeability of nicotine across the oral mucosa had been shown to be a direct linear function of alkalinity in the oral cavity. Here, oral pH in cigarette smokers was manipulated from pH 5 to 8 by rinses with Sorenson's and McIlvaine's buffers. As a alkalinity increased, cigarette taste was perceived as stronger, more bitter, and, in some cases, more upleasant; and heart-rate accelerated slightly. Nicotine self-administration and blood pressure were not influenced. Differential absorption of nicotine and cross-adaptation of sour to bitter taste are both discussed as explanations for the results.

Blood Pressure↗
PubMed1978

Pituitary-adrenal axis and oral morphine consumption in rats.

Removal of the pituitary gland in rats leads to suppression of oral morphine and quinine intake behavior. Experiments measuring oral intake of solutions containing graded concentrations of morphine or quinine, revealed that the detection acuity for bitter taste is changed in hypophysectomized (hypox) animals. Treatment of these rats with ACTH 1--24 restored oral morphine intake towards that on intact rats. Morphine consumption in hypox rats was not affected by administration of ACTH 4--10 or ACTH 11--24, but was normalized by treatment with corticosterone. Adrenalectomy also diminished oral morphine intake. It is concluded that hypophysectomized animals refuse a morphine solution because their threshold for bitter taste quality is altered, presumably due to a diminished release of corticosteroids.

Adrenalectomy↗
PubMed2026

Predicting food taste with bound-driven optimization.

The prediction of sensory attributes from ingredient-level formulations is an emerging challenge at the intersection of food science and artificial intelligence. We address the fundamental question of whether the taste of a food can be predicted from its ingredients by treating recipes as composite materials. We apply Hashin-Shtrikman (HS) and Reuss-Voigt (RV) bounds, techniques originally developed for elastic moduli, as a null-hypothesis additive baseline for five taste dimensions (sweetness, sourness, bitterness, umami, saltiness) on a curated dataset of 70 recipes decomposed into 115 distinct ingredients scored against a library of 209 ingredient-level taste references with trained-panel ground truth. This baseline systematically under-predicts perceived taste: 77% of actual taste values exceeded the HS upper bound, with the exceedance rate ranging from 26% (bitterness) to 97% (saltiness). We traced this gap to specific processing chemistry (Maillard reactions, caramelization, evaporative concentration, protein hydrolysis, and nucleotide synergy) and introduced a hybrid model that augments the HS baseline with eight chemistry-proxy features encoding these mechanisms. Our results show that our interpretable hybrid model eliminates the systematic bias and reduces mean absolute error by 27%-62% for sweetness, sourness, umami, and saltiness while using only 10 interpretable features, achieving performance comparable to a black-box Lasso regression on 115 per-ingredient features. We further demonstrate constrained inverse design via Differential Evolution, recovering ingredient formulations that match target taste profiles subject to compositional bounds. Our work demonstrates how key chemical processes during food preparation can inform and augment physics-based and machine learning models, providing a quantitative fingerprint of processing chemistry's contribution to taste perception and paving the way for model-driven food formulation with targeted sensory characteristics.

Composite material bounds↗
PubMed2026

Genetics of sensory nutrition.

Sensory nutrition is an emerging research area that examines how chemosensory perception, particularly taste and smell, shapes dietary behaviours, nutritional status, and disease risk. Variation in how individuals perceive the same foods may help explain differences in diet quality and responsiveness to behavioural dietary interventions, yet chemosensory phenotypes are rarely measured at the population level. Genetic variation contributes to this perceptual diversity and provides a framework for investigating sensory determinants of diet using genomic approaches. This review summarises evidence linking chemosensory genetics to perception and dietary behaviours, and discusses applications for causal inference and for precision and personalised nutrition. Twin studies reveal moderate to high heritability for bitter taste traits, with more modest and phenotype-dependent estimates for sweetness, sourness, saltiness, fat-related traits, and olfactory measures. Genome-wide association studies have identified loci in taste and olfactory receptor genes associated with specific chemosensory traits as well as liking and intake of various foods, although the evidence remains concentrated on bitter taste and populations of European ancestry. These genetic variants have been used in Mendelian randomisation, a genetics-based approach that strengthens causal inference, to test whether sensory traits influence dietary behaviour. For precision nutrition, evidence for taste genotype-stratified interventions remains limited and mixed. Realising the promise of sensory nutrition will require scalable and standardised chemosensory phenotyping, Findable, Accessible, Interoperable, and Reusable (FAIR) data infrastructure, expanded research in diverse populations, and integration with broader biological and sociocultural determinants of dietary intake.

Genetics↗
PubMed1978

Altered taste thresholds in lung cancer.

Taste threshold levels for the four basic taste modalities were determined in 30 male lung cancer subjects and 30 male control subjects who had no history of malignant disease. Lung cancer patients demonstrated significant alteration in taste recognition for sour but not for bitter, sweet, or salt. There were, however, quantitative differences between cancer patients and control subjects in recognition thresholds for the sweet taste modality. Some of the lung cancer subjects had demonstrated greater sensitivity to the taste of bitter than the control subjects and others were less sensitive. These alterations may account in part for the reduction of intake and for the aviodance of certain food items by lung cancer subjects. Dietary histories should be taken on all cancer patients in order to individualize dietary management, thereby improving the nutritional intake.

Adult↗
PubMed1978

Enzymatic hydrolysis of soy protein for nutritional fortification of low pH food.

Enzymatic hydrolysis of proteins is an attractive means of obtaining the changes in the functional properties often necessary for incorporating the protein in low pH food, e.g. soft drinks. The main problem associated with protein hydrolysis is the welldel-known formation of bitter-tasting peptides. The bitterness seems to be related to a too high degree of hydrolysis (DH). DH is defined as the percentage of cleaved peptide bonds and serves as the controlling parameter for the hydrolysis process. The choice of hydrolysis parameters is briefly discussed in relation to studies on the hydrolysis kinetics which in many respects can be described by classical enzyme kinetics. Several pilot plant productions of isoelectric soluble soy protein hydrolyzates have been carried out using soy isolate or soy concentrate as the raw material. The preferred enzyme for this type of hydrolysis is Alcalase 0.6 L, a food-grade liquid preparation of subtilism Carlsberg. The chosen hydrolysis parameters are : Substrate conc. : 8 per cent protein (N x 6.25). Enzyme-substrate ratio : 2 per cent. pH : 8.0. Temperature : 50 degrees C. The optimal DH value with regard to taste seems to be 10 per cent, corresponding to about 2 hours' hydrolysis time. The hydrolysis is terminated by the addition of citric or malic acids until pH reaches a value of 4.2. Separation of the supernatant from the unconverted protein is carried out in a continuous, solids-ejecting centrifuge. Preliminary rat trials show a satisfactory nutritional quality of the hydrolyzates. Possible end-uses for soy protein hydrolyzates are briefly discussed.

Food, Fortified↗
PubMed1978

[Verification of the plum pox virus (PPV) using the tray test (author's transl)].

A comparison of 6 host plants reacting by local lesion if infected by the Plum Pox Virus (PPV) demonstrated that beside Chenopodium foetidum Schrad. also Nicandra physaloides (L). Gärtner, Nicardra physaloides violacea Bitter and Verbena officinalis L. are pretty well suitable to verify the PPV serving as locally reacting test plants. Using the tray test, the PPV was verifiable by separated leaves of C. foetidum Schrad., N. physaloides violacea Bitter, N. physaloides (L.) Gärtner and V. officinalis L. Applying experimental conditions precisely defined, an abridgement of the period between infections and development of the symptomes by three days was acquired here, compared with the plant test.

Methods↗
PubMed1978

[Disturbances of taste from oral disinfectants (author's transl)].

Oral disinfectants containing chlorhexidine or hexetidine are able to produce disturbances of taste, as demonstrated by Krarup's electrogustometric method and the gustometric method of Harris and Kalmus. Hypo- and dysgeusia are characterized by dissociated disturbances, the most prominent of which concerns the sweet perception. The bitter taste is least affected, whereas the effects on salty and acidic tastes range between that for sweet and bitter. Taste disturbances which include ageusia for 48 h were observed when the tongue was touched with a 20% solution of chlorhexidine. Not only the disinfectants themselves provoked dysgeusia but also other "taste improving" agents (particularly, the volatile oild). In addition to dysgeusia, the authors found disturbances of the mucous membrane sensitivity caused by the test substances.

Adult↗
PubMed2026

The genome sequence of Cardamine flexuosa With., 1796 (Brassicales: Brassicaceae).

We present a genome assembly of Cardamine flexuosa (Wavy Bitter-cress; Streptophyta; Magnoliopsida; Brassicales; Brassicaceae). The genome sequence has a total length of 204.54 megabases. Most of the assembly (97.53%) is scaffolded into 8 chromosomal pseudomolecules. The mitochondrial sequence has a length of 299.98 kilobases and the plastid genome assembly has a length of 153.92 kilobases. Gene annotation of this assembly on Ensembl identified 24 305 protein-coding genes. This assembly was generated as part of the Darwin Tree of Life project, which produces reference genomes for eukaryotic species found in Britain and Ireland.

Brassicales↗
PubMed1978

The clinical significance of gallstones and their radiological investigation.

The symptoms of 122 patients with gallstones were correlated with the radiological findings. No specific indigestion was present which could be termed 'flatulent dyspepsia'. Sensitivity to fatty foods occurred in 69 per cent, heartburn in 42 per cent, regurgitation of of acidtasting or bitter fluid to the mouth in 31 per cent and increased passage of flatus from the stomach upwards in 38 per cent. If the gallbladder concentrated contrast medium or an oral cholecystogram but did not contract after a fatty meal, the patients suffered less heartburn than if the gall bladder functioned normally. However, since surgeons rarely perform a cholecystectomy for flatulent dyspepsia alone, knowlege of gallbladder function may be unnecessary.

Adult↗
PubMed1977

The physical aspects with respect to water and non-enzymatic browning.

Non-enzymatic browning is one of the major probles that occurs during the processing and storage of dehydrated and semi-moist foods. One type of browning is the Maillard reaction between reducing sugars and proteins or free amines. This leads to a darkening of color, protein insolubility with subsequent possible nutrition loss and a bitter off-flavor. The reaction has been extensively researched since the early 1940's. From a storage standpoint, browning rate increases as water activity (aw) increases up to a maximum where reactant dilution causes a subsequent decrease in rate. Use of liquid humectants in high moisture foods increase phase volume and viscosity, thereby lowering the aw of the rate maximum. These humectants thus act as inhibitors at high aw. Sorbitol also decreases the rate by a viscosity effect. Kinetic studies at normal storage conditions show browning to occur by a zero order reaction although the sugar and amine initial reaction occurs by first order. Studies with Tetrahymena show that the initial Schiff's base and reaction products may be partially biologically available although chemical assays show up to 50% loss of protein value. For dehydrated foods the zero order kinetics can be used to predict shelf life under a variable time-temperature-humidity condition.

Cellulose↗
PubMed1975

Effect of two weeks' treatment with thioridazine, chlorpromazine, sulpiride and bromazepam, alone or in combination with alcohol, on learning and memory in man.

Forty paid healthy male students participated in two subacute experiments of 6 weeks each. In the first trial 20 of them received bromazepam, thioridazine, and placebo double blind cross over for 2 weeks each, and in the second trial the active agents administered to the other 20 participants were chlorpromazine and sulpiride. The tests used were paired associate learning with nonsense syllables and digit memory span. Before testing the subjects took either an alcoholic or a nonalcoholic bitter drink. As in the previous study from this laboratory, alcohol was found to impair learning capacity. Of the drugs used only bromazepam impaired learning significantly, and the combined effect of alcohol and bromazepam on learning capacity was very deleterious. The adrenolytic effect of drugs did not correlate with their effect on learning. Caution is necessary when prescribing bromazepam for active outpatients at least in doses used in this study.

Adult↗
PubMed1978

The attenuation of a specific cue-to-consequence association by antiemetic agents.

Previous research has been shown that rats develop a conditioned taste aversion after a single pairing of a distinct taste and subsequent toxicosis. The experiments reported here test the hypothesis that the expression of a taste aversion may reflect classically conditioned nausea mediated by activation of brainstem emetic centers by taste stimuli. Rats were allowed to drink a saccharin solution (1 g/l) and 10 min later were intubated with LiCl (180 mg/kg) to produce nausea. When control rats were posttested for saccharin preference they consumed less than 50% of their pretest intake. Experimental rats were injected with one of four pharmacologically distinct antiemetic drugs 30 min prior to their posttest with saccharin. Each drug significantly attenuated the aversion to saccharin at one dose level. The antiemetic drugs we used were scopolamine HBr, cyclizine, prochlorperazine dimaleate, and trimethobenzamide. These drugs had no effect on the conditioned fear of a noise that signaled foot shock or on a natural aversion to a bitter fluid (quinine monohydrochloride, 100 mg/l). Our data suggest that pharmacological suppression of the neural mechanisms of emesis selectively disrupts conditioned taste aversions, and that moderate dose levels are critical for obtaining this effect.

Animals↗
PubMed1976

Taste qualities elicited by electric stimulation of single human tongue papillae.

Single human taste papillae in 5 young test subjects were electrically stimulated 84 times each with a silver wire (0.4 mm tip diameter) versus a 5 x 3.5 cm2 reference electrode on the left wrist of the subject. The electrical pulses were positive (54 papillae) or negative (45 papillae) of 0.5 msec duration and had a frequency of 50, 100, 200, 400, 600 or 800 Hertz. For control 45 papillae were merely touched by the electrode without current stimulation. Significant gustatory and tactile results (x2-test, P less than or equal to 0.05) signaled by the subjects were: a) on anodic stimulation 50 +/- 5% of the touched papillae gave overall taste responses, namely 22.2% sour, 3.8% bitter and 1.8% salty; the rest were mixed sensations. Sweet was not reported in these final experiments; b) on cathodic stimulation 42.2 +/- 5% of the papillae responded with taste, which again were reported as 22.2% sour, 2.2% salty, the rest mixed; c) on mere touching there were hardly any gustatory sensations reported. - These results indicate only a relative specifity for each single human taste papilla and its taste fibres.

Adolescent↗