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• Acidification can occur during storage of Congou black tea. • Aroma enhancement process (AEP) accelerates acidification of black tea during storage. • AEP promotes conversion of Phenylalanine and glucose to oxalic acid, quinic acid, etc. • AEP also changes tea soup composition and increases acidification during storage. Acidification of aroma-enhanced black tea during storage was studied. UPLC-Q-TOF/MS (Ultra Performance Liquid Chromatography and Quadrupole-Time of Flight Mass Spectrometer) and HPLC (High-Performance Liquid Chromatography) analysis of non-volatile substances and organic acids revealed a decrease of soluble sugars and amino acids in aroma-enhanced black tea, while an increase in organic acids such as oxalic acid, malic acid and quinic acid. Further in vitro experiments indicated that the acidification of aroma-enhanced tea during storage can be attributed to decomposition of sugars and amino acids by heating, oxidation of aromatic aldehydes. Meanwhile, the amino acids, catechins, soluble sugars and flavonoids that constitute the taste of black tea are further reduced, changing the taste composition of tea infusion and further increasing its acidity. This study revealed the reasons for black tea acidification during aroma enhancement and storage and provided a theoretical basis for improving black tea quality. [ABSTRACT FROM AUTHOR]

[Display omitted] • Barriers to vegetable food acceptance were investigated with a multidimensional approach. • Heightened perception of warning sensations reduced the acceptance of vegetable food. • High expression of anxiety related traits associated to low preference for vegetable foods. • Adoption of food models varying in target sensations improved food behaviors interpretation. The innate aversion to warning sensations is an important barrier to the acceptance of vegetable food often characterized by bitter and sour tastes, and astringency. Large individual variations exist in preference for this food category. The present study aimed at exploring differences in demographics, anthropometrics, taste responsiveness, personality traits and attitudes in consumers differing in their preference for vegetable food with varied levels of warning sensations. A panel of Italian consumers (n = 718; 53.6% women, age 18–74 years) self-reported familiarity with, preference for and choice of vegetables with high and low levels of warning sensations. Two clusters were identified: High Warning-Vegetable Consumers (HWVC, n = 464) and Low-Warning Vegetable Consumers (LWVC, n = 254). HWVC showed higher familiarity with and preference for vegetables as a whole and higher choice of vegetables characterized by warning sensations than LWVC. HWVC were more represented by older and normal weight individuals as compared to LWVC. Differences among clusters in liking for and perception of a phenol-enriched plant-based food model specifically developed to induce different levels of bitterness, sourness and astringency were found. HWVC rated bitterness, sourness, and astringency lower and liking higher than LWVC. Scores in anxiety-related psychological traits were lower while attitudes to healthy and high-quality food choice were higher in HWVC than in LWVC. The results of the present study depicted a coherent interplay among several person-related dimensions in modulating preference for vegetable foods. Higher responsiveness to warning sensations, higher level of anxiety-related traits, lower importance assigned to food healthy/quality aspects and younger age all acted as barriers to exposure and acceptance of vegetable food and call for a multidimensional approach to promote the consumption of this food category. [ABSTRACT FROM AUTHOR]

Abstract: Decreasing the sodium content in food products without changing consumer acceptability has become an important challenge for the food industry, and several strategies are currently under investigation to reach this goal. This study investigated the effectiveness of saltiness enhancement by an odour to maintain the perception of saltiness in reduced salt content solutions. In the first experiment, we tested the hypothesis that odour intensity drives the level of saltiness enhancement. The results showed that odour can increase the salty intensity by 25%, while no clear influence of odour intensity either in tasteless solutions or in low-salt content solutions. In a second experiment, we examined whether odour could enhance saltiness in salty solutions containing potassium chloride alone or mixed with sodium chloride and in salty-sour solutions. The results showed that a higher Odour-Induced Saltiness Enhancement occurred when the salty taste relied on potassium chloride as compared to sodium chloride. However, the highest enhancement was observed in the ternary odour–sour-salty solution. These findings suggest that cross-modal odour(s)–taste(s) interactions may be an efficient strategy, in combination with the use of salt replacers, to compensate for sodium reduction in complex food systems. [Copyright &y& Elsevier]

Abstract: Samples of dilute HCl intended to result in mixtures with saliva with pH levels below, near and above the level of maximum protein–polyphenol interaction were presented to panelists. Significant differences in astringency were seen, but no evidence of a decline in astringency with stronger acid. Panelists abstained from tea drinking for some time, then drank two or more cups of green tea per day for some days, and finally omitted tea drinking for a period. Salivary polyphenol levels were determined throughout the experiment. Drinking green tea resulted in a highly significant (p <0.01) increase in salivary polyphenol levels that persisted for some days. Very dilute HCl solutions (0, 0.005, 0.006 and 0.007N) were presented to panelists before, during and after the period of tea drinking and rated for astringency and sourness. Astringency and sourness intensity ratings increased significantly (p <0.01) during the period of tea drinking. It appears that there is a metabolic pool of polyphenol that is influenced by dietary habits. It appears likely that the salivary polyphenol level influences perception of astringency caused by acids. [ABSTRACT FROM AUTHOR]

Abstract: Our objective was to assess six palate cleansers and two cleansing protocols for their ability to limit buildup and enhance discrimination of tannin-containing and acidic astringent solutions. Palate cleansers included water, carboxymethylcellulose, crackers, milk, chewing wax, or nothing. Twenty-nine panelists, randomly divided into two groups, participated in a 12-session series in which they rated the astringency of either six tannin or hydrochloric acid solutions. Panelists used a single palate cleanser at each session according to one of two cleansing protocols. The palate cleansers did not differ in their ability to prevent astringency buildup from occurring. Panelists were best able to discriminate among the astringency of the tannin solutions when water or nothing was used as a palate cleanser. Water or nothing also improved discrimination among the acid samples, but only at low levels of astringency. Astringency discrimination and buildup were not affected by the cleansing protocol. Our results indicate that using water or nothing as a palate cleanser will facilitate detection of sensory differences of astringency. [Copyright &y& Elsevier]

Abstract: The purpose of this study was to evaluate the palatability of 15 bottled nutritive drinks, all commercially available in the Japanese market, using data from artificial taste and odor sensors. In gustatory sensation tests, well-trained healthy volunteers were asked to score the drinks in terms of palatability and of the four basic tastes. The results suggest that overall palatability is positively correlated with sourness intensity and fruitiness (R =0.82 and 0.86, respectively) and negatively correlated with bitterness intensity and the tasting of medicinal plants (R =−0.85 and −0.80, respectively). The sourness and bitterness intensity could be predicted by taste sensor and fruitiness could be predicted by odor sensor, respectively. By performing principal component analysis of the taste sensor data, the 15 drinks could be classified into four groups. The group classified as being predominantly sour had the highest palatability score, 3.8. By principal component analysis of odor sensor data, the drinks could also be classified into four groups and this time the group with a fruity flavor (smell) showed the highest palatability score, 3.4. In the combined analysis of both taste and odor data, products containing medicinal plants showed the lowest palatability. Finally, the combined usage of the taste and odor sensors gave rise to a three-group classification. Thus, not only the taste sensor but also the odor sensor may be useful in evaluating the palatability of bottled nutritive drinks. [Copyright &y& Elsevier]

The purpose of this study was to evaluate the taste of 20 bottled nutritive drinks, all commercially available on the Japanese market, both in human gustatory sensation tests and using a multi-channel taste sensor. In the gustatory sensation tests, seven trained healthy volunteers were asked to score the drinks in terms of the intensities of four basic tastes (sweetness, saltiness, sourness, and bitterness), for overall palatability (ease of drinking), and for nine components of palatability (astringency, pungency, fruitiness, tasting of a medicinal plant, refreshing, irritating to the throat, seeming beneficial, good aftertaste, and the desire to drink again). The data were analysed to determine the critical factors for overall palatability.There was a positive linear correlation between overall palatability and ‘sourness’, ‘fruitiness’, ‘refreshing’, and ‘good aftertaste’ scores (r = 0.79, 0.85, 0.74, and 0.70, respectively). There was a negative correlation between overall palatability and ‘bitterness intensity’, ‘tasting of a medicinal plant’, ‘seeming beneficial’, and ‘pungency’ scores (r = -0.76, -0.64, -0.62, and -0.50, respectively).When evaluated using a multi-channel taste sensor, there was a positive linear correlation between the intensities of sourness and bitterness determined by the human volunteers and those predicted by the taste sensor (r = 0.85 and 0.71, respectively). The pungency intensity, as evidenced in gustatory sensation tests, could be also predicted by sensor output (r = 0.84). The taste sensor seems therefore to be a potentially useful tool in evaluating the palatability of bottled nutritive drinks. [Copyright &y& Elsevier]

• A strategy was outlined for the exploitation of high-quality unripe grapes. • The food composition affected both the phenol recovered and antioxidant activity. • The highest recovery of phenols was from the starch/neutral pH food model. • The highest antioxidant activity was from the carbohydrates/acidic pH food model. • The models' sensory properties are modulated by phenol content and food composition. Unripe grapes (UGs) from thinning are an unexploited source of phenols useful as functional ingredient. However, phenols may negative affect sensory quality of food. Chemical and sensory properties of UG phenols in plant-based foods were not investigated before. With this aim, an extract from UGs, obtained by a green extraction technique, was used to fortify three plant-based food models: carbohydrates/acidic pH/sweet – beetroot purée, proteins/neutral pH/sweet – pea purée and starch/neutral pH – potato purée. Functional and sensory properties of phenol-enriched foods varied as a function of their composition and original taste. The amount of UG phenols recovered from potato purée was higher than that recovered from beetroot and pea purée, while the antioxidant activity detected in beetroot purée was higher than that in potato and pea purée. Significant variations of sourness, saltiness, bitterness and astringency were induced by UG phenols added to food models. Beetroot purée resulted more appropriate to counteract the negative sensations induced by UG phenols. [ABSTRACT FROM AUTHOR]

Summary The decision to consume or reject a food based on the degree of acidity is critical for animal survival. However, the gustatory receptors that detect sour compounds and influence feeding behavior have been elusive. Here, using the fly, Drosophila melanogaster , we reveal that a member of the ionotropic receptor family, IR7a, is essential for rejecting foods laced with high levels of acetic acid. IR7a is dispensable for repulsion of other acidic compounds, indicating that the gustatory sensation of acids occurs through a repertoire rather than a single receptor. The fly's main taste organ, the labellum, is decorated with bristles that house dendrites of gustatory receptor neurons (GRNs). IR7a is expressed in a subset of bitter GRNs rather than GRNs dedicated to sour taste. Our findings indicate that flies taste acids through a repertoire of receptors, enabling them to discriminate foods on the basis of acid composition rather than just pH. Graphical Abstract Highlights • Drosophila exhibit distinct attraction and repulsion to different carboxylic acids • A variant ionotropic receptor (IR7a) is narrowly tuned for rejecting acetic acid • IR7a is required in bitter gustatory receptor neurons for avoiding acetic acid • Acetic-acid-induced action potentials depend on IR7a The receptors required for the gustatory responses to sour compounds have been elusive. Rimal et al. discover a Drosophila taste receptor, IR7a, which is required for rejecting a sour chemical. Surprisingly, IR7a is narrowly tuned to acetic acid, suggesting that carboxylic acids are detected by a repertoire of receptors. [ABSTRACT FROM AUTHOR]