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Persimmon is classified as either pollination-constant non-astringent (PCNA) or non-PCNA on the basis of the loss of astringency in fruit. PCNA trait of persimmon has attracted much research attention owing to its economical merit, as there is no cost in removing astringency. To efficiently develop new PCNA cultivars in crossbreeding, marker-assisted selection plays a crucial role. Here, we describe a cleaved amplified polymorphic sequence (CAPS) marker that can be used to select PCNA persimmon. A sequence-characterized amplified region (SCAR) marker used to screen for PCNA offspring is unsuitable for populations recently derived from two non-PCNA parents ('Yoshidagosho' and 'Toyoichi'), resulting in the selection of non-PCNA offspring as PCNA. To detect specific polymorphisms for these non-PCNA offspring, we analyzed fragment sizes of SCAR marker products by capillary DNA sequencing. A slightly lower-molecular-weight fragment at 353 bp was specifically detected in non-PCNA offspring but not in PCNA offspring. We treated the SCAR marker products with the StuI restriction enzyme and demonstrated that the smaller 353-bp fragment corresponded to allele a353-1, one of four previously identified sequence polymorphisms at the 353-bp peak, and a353-1 is linked to non-PCNA trait. Comprehensive analysis of 130 germplasms by the CAPS marker, detecting the truncated fragment after StuI treatment, indicated the presence of a353-1 in 38 non-PCNA cultivars. Our findings suggest the potential use of the CAPS marker for selecting PCNA offspring derived from these 38 non-PCNA cultivars. [ABSTRACT FROM AUTHOR]

Consumption of plant-based food products having high composition of polyphenols leads to the sensation of astringency. For sliding oral surfaces, friction is an essential property during the oral perception of roughness and dryness which are attributes associated with astringency. Different factors including the chemical composition of interacting layers, structure and operation of interfaces have an effect on the astringency development process. The manner of interactions occurring at oral interfaces suggest there is a system dependence of astringency and highlights the importance of adopting a tribosystems approach. Available measurement techniques have shown an existing relationship between salivary protein-polyphenol interaction and an astringent mouthfeel. Nevertheless, the tribo-chemistry involved in this multifaceted sensation remains largely unexplored in a comprehensive manner. In this review the underlying tribo-chemical processes useful in understanding the mechanism of astringency are highlighted and discussed considering current techniques employed to investigate astringency perception. Loss of lubrication on oral surfaces owing to the tribo-chemical interactions involving saliva and astringent plant proteins requires subsequent deformations of oral tissues which are significant enough to induce strains at mechanoreceptor locations, leading to the sensation of astringency. It is proposed that micro-scale contact modelling on the interaction of food particles/aggregates, boundary layers and oral surfaces shows potential in addressing the knowledge gap between tribo-chemical measurement techniques and panel tests, making it possible to attain a predictor for astringency. [ABSTRACT FROM AUTHOR]

Oat-based milk alternatives (OMAs) are an important alternative to bovine milk, with prevalence of lactose intolerance, as well as soy and nut allergies limiting consumers options. However, OMAs are typically lower in protein content than both bovine milk and soy-based alternatives, with protein quality limited by low lysine levels, which can reduce protein digestibility. Addition of alternative plant proteins may increase the quantity of protein, as well as balancing the amino acid profile. However, plant-based proteins have additional sensory qualities and off-flavours, which may lead to undesirable characteristics when introduced to OMAs. This study aimed to assess the effect of pea and potato protein addition on the sensory profile, volatile profile, colour, and particle size in an OMA control product. Results demonstrated that pea protein contributed to a bitter and metallic taste, astringent aftertaste, and a significantly increased overall aroma correlated with higher levels of key volatiles. Whilst potato protein resulted in less flavour changes, it did lead to increased powdery mouthfeel and mouthcoating supported by a substantially increased particle size. Both protein fortifications led to detectable colour changes and a staler flavour. Fortification of OMA product with the pea protein led to significant sensory, volatile and physical changes, whilst the potato protein led to predominantly physical changes. Further investigation into alternative plant-based proteins is necessary to optimise sensory qualities whilst increasing protein content and the amino acid profile. [ABSTRACT FROM AUTHOR]

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Cyanidin 3-O-glucoside (C3G) is believed to combine with oral mucin, thus impairing oral lubrication and leading to the development of oral astringency. When C3G is oxidized into cyanidin 3-O-glucoside quinone (C3GQ), it might covalently interact with cysteine of mucin to enhance astringency. Herein, their detailed interactions at the molecule level were characterized through spectroscopy, isothermal titration calorimetry and determination of free amino and sulfhydryl groups. The results showed that hydrogen bond and van der Waals force were the predominant non-covalent interactions. Furthermore, C3GQ could additionally bind to mucin by forming C-N and C-S bonds since the amino and sulfhydryl groups of mucin decreased by 0.48 mmol/g and 4.14 µmol/g after reacting with C3GQ. Besides, C3GQ had stronger interaction with mucin as the exothermic value of Muc-C3GQ (2513 KJ/mol) was larger than Muc-C3G (60.4 KJ/mol). These findings may explain the phenomenon of increased astringency of anthocyanins after being oxidized into quinones. [ABSTRACT FROM AUTHOR]

The clear juice fermentation technique for white wines suggests that white grape seeds, rich in flavan-3-ols and proanthocyanidins, are not effectively utilized in the winemaking process. This study incorporated ‘Gewürztraminer’ grape seeds into ‘Cabernet Sauvignon’ must before cold soak to investigate how the resultant red wines' phenolic compound profiles, color, and astringency were affected. The results showed that adding seeds primarily inhibited the leaching of flavan-3-ols from both skins and seeds. A significant increase in the levels of flavan-3-ols, tannins, and phenolic acids, as well as direct and aldehyde-bridged flavan-3-ol-anthocyanin polymers, were observed in the wines with additional seeds. This led to the improvement in the wine’ red hue and its resistance to SO2 bleaching. Furthermore, the wine added with seeds exhibited stronger astringency compared to those without. The findings provide a promising winemaking strategy to improve color stability and intensify the astringency of red wines through the utilization of grape seeds.

Plums (Prunus salicina and Prunus domestica) are prevalent in southwestern China, and have attracted interest owing to their delectable taste and exceptional nutritional properties. Therefore, this study aimed to investigate the nutritional and flavor properties of plum to improve its nutritional utilization. Specifically, we determined the soluble sugars, organic acids, and phenolic components in 86 accessions using high-performance liquid chromatography. Notably, glucose, fructose, malic, and quinic acids were the predominant sweetness and acidity in plums, with sucrose contributing more to the sweetness of the flesh than the peel. Moreover, The peel contains 5.5 fold more phenolics than flesh, epicatechin, gallic acid, and proanthocyanidins C1 and B2 were the primary sources of astringency. Correlation and principal component analyses showed eight core factors for plum flavor rating, and a specific rating criterion was established. Conclusively, these findings provide information on the integrated flavor evaluation criteria and for enhancing optimal breeding of plums.

Dry red wines can be sourced from the Ningxia and Xinjiang regions of China. This study aims to characterize the taste quality, according to the conventional and easily measurable polyphenol series indices. The UV-Vis spectrophotometer was used to detect the conventional polyphenols in wine. A predictive model was constructed to evaluate the astringency and aftertaste of dry red wine using the polyphenol indices. A total of 50 (Cabernet Sauvignon) dry red wines were selected as the research objects (20 from Ningxia and 30 from Xinjiang, each from different small producing areas). The total acidity, volatile acidity, and pH of the wines were tested to evaluate the acidity, according to GB/T 15038-2006. The antioxidant activity of wine was determined by DPPH scavenging activity. Total phenols were determined with the UV-Vis spectrophotometer using the Folin-Ciocalteu method. Flavanol content was determined by p-DMACA hydrochloric acid. The contents of tartrate (A320), flavonol (A360), and total anthocyanins (A520) in the wines were determined at different absorbance levels. The aftertaste and astringent sensation were evaluated using the quantitative sensory description in Panel Check software. Correlation analysis (CA) was used to analyze the interaction between the indices of the wine polyphenol series, and linear discriminant analysis (LDA) was to easily distinguish different regions. The modeling samples were analyzed with the principal component analysis. The taste quality of wine samples was characterized and predicted with partial least squares regression. The CA results indicated that there were significant differences (P<0.05) in the effects of total phenols, anthocyanins, flavanols, and flavonols on the astringency and aftertaste of the dry red wines. However, there was a minimal impact of tartrate on the aftertaste. Furthermore, the total acids and pH had no significant (P>0.05) effect on the astringency of the wine. Taking the Yongning region of Ningxia as an example, LDA easily differentiated dry red wine samples from the Yongning of Ningxia and the Xinjiang region using polyphenol series indices. Two discriminant functions generated by LDA were used to explain 80.8% and 19.2% of the variance, respectively. The accurate discriminant rate of 80.0% was obtained after classification. While there was the correct discriminant rate of 62% after the cross-validation. The sensory evaluation showed that the astringency scores were 6.18 and 5.70, in Ningxia and Xinjiang wine samples, respectively, while the aftertaste scores were 5.37 and 4.85, respectively. Therefore, the total phenols, anthocyanins, flavanols, flavonols, and DPPH contributed significantly to the astringency and aftertaste of wine. Tartrate mostly influenced the wine astringency, whereas the total acids and pH dominated the wine aftertaste. Polyphenol indices with cost-saving UV-Vis spectrophotometers can be expected to better assess the taste quality of dry red wine. The sample size can be increased to promote the taste quality of dry red wine for the accuracy and stability of the model. [ABSTRACT FROM AUTHOR]

Astringency has an important impact on the taste quality of tea infusion, a process which occurs when polyphenols complex with salivary proteins to form an impermeable membrane. (-)-Epigallocatechin gallate (EGCG) is the main astringent compound found in green tea and mucin is the main protein present in saliva. Determining the turbidity of EGCG–mucin mixtures is an effective method to quantify the astringency intensity of EGCG solutions. In this study, the effects of taste-related, substances present during green tea infusion, on the turbidity of EGCG–mucin mixtures was investigated under the reacting conditions of a pH value of 5.0, at 37 °C, and for 30 min. The results showed that epicatechins, caffeic acid, chlorogenic acid, and gallic acid reduced the turbidity of EGCG–mucin mixtures, while rutin increased turbidity. Metal ions increased the turbidity of EGCG–mucin mixtures. These can be arranged by effectiveness as Al3+ > K+ > Mg2+ > Ca2+. Caffeine, theanine, and sodium glutamate all decreased the turbidity values of EGCG–mucin mixtures, but sucrose had a weak effect. Further experiments confirmed that the turbidity of green tea infusion–mucin mixture indicated the astringent intensity of green tea infusion, and that the turbidity was significantly correlated with the contents of tea polyphenols and EGCG. [ABSTRACT FROM AUTHOR]

Long-term intake of procyanidins has been suggested to reduce the risk of cardiovascular disease, dementia, and sensory function decline associated with aging. However, most of the ingested procyanidins are not absorbed and are excreted in the feces, so the mechanism of their beneficial impact is unknown. Procyanidins are the components of astringency in plant foods and their stimulation appears to be directly transmitted to the central nervous system via sensory nerves. Recent attention has been focused on the taste receptors expressed in the extra-oral gastrointestinal tract may regulate homeostasis via the neuroendocrine system. In this paper, we have reviewed recent findings on the relationship between the astringency of procyanidins and their bioregulatory effects. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chinese Institute of Food Science & Technology is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

AbstractThe stability of the all-solid-state electrode (ASSE) is influenced by its fabrication procedure, which has been insufficiently investigated. In this study, we report that by applying direct annealing of solid contact (polypyrrole-carbon black [PPy-CB]), and slow-drying the membrane during fabrication, electrode capacitance is improved which determines the stability of the ASSE-based astringent taste sensor. The deposition of the PPy-CB by direct annealing accelerated the sensor fabrication time and improved the capacitance. The slow-drying method led to a thinner and denser membrane, which consequently reduced bulk and charge-transfer resistance and improved the electrode capacitance. In synergy with the annealed PPy-CB, the proposed sensor exhibited an areal capacitance of 9090 μF/cm2. In addition, the sensor maintained its linear response to the standard astringent substance (tannic acid), selectivity against various interfering taste substances, and retained repeatable measurements for at least 27 d. [ABSTRACT FROM AUTHOR]

The astringency of persimmon fruits is a significant factor for consumers and the nutritional industry. To date, astringents, such as polyphenols, specifically persimmon condensed tannins, have been assessed using polyphenol quantification assays, such as the Folin-Ciocalteu method, based on their reducing power. However, these methods are influenced by the presence of other reducing substances. In this study, we developed a cost-effective liposome turbidity analysis using a portable visible spectrophotometer based on the interaction between liposomes and astringents. Authentic astringents, such as catechins and theaflavin-3-O-gallate, were analyzed, and their half-maximal effective concentrations (EC50) were calculated. These results indicated that the affinity to the membrane was similar to that of astringency, as determined by sensory analysis. Additionally, the EC50 values of partially purified tannins from non-astringent and astringent persimmons were calculated. In conclusion, we determined the application methods to assess astringent persimmon fruits with and without the removal of astringency. [ABSTRACT FROM AUTHOR]

Recent studies have demonstrated that the interaction of dietary constituents with taste and olfactory receptors and nociceptors expressed in the oral cavity, nasal cavity and gastrointestinal tract regulate homeostasis through activation of the neuroendocrine system. Polyphenols, of which 8000 have been identified to date, represent the greatest diversity of secondary metabolites in plants, most of which are bitter and some of them astringent. Epidemiological studies have shown that polyphenol intake contributes to maintaining and improving cardiovascular, cognitive and sensory health. However, because polyphenols have very low bioavailability, the mechanisms of their beneficial effects are unknown. In this review, we focused on the taste of polyphenols from the perspective of sensory nutrition, summarized the results of previous studies on their relationship with bioregulation and discussed their future potential. [ABSTRACT FROM AUTHOR]

Summary: Due to the surplus in the production of 'Rojo Brillante' persimmon in Spain, there is great interest in developing products made from this fruit that can take full advantage of production peaks. However, heat treatment can reverse the astringency, limiting the diversity of products derived from persimmon. The aim of this study was to characterise physicochemically astringent and non‐astringent persimmon cremogenates subjected to pasteurisation and elaborated with different thickeners (guar gum, sodium alginate and pectin). Several aspects were specifically analysed: the evolution during the storage of the soluble solid content, water, total phenols, antioxidant capacity, optical and mechanical properties, as well as the microbiological stability. The sensory acceptability of the selected cremogenates was also evaluated. The results showed that the final colour of the samples depended on the initial level of astringency of the raw material; the non‐astringent persimmons were much darker (L* ≈ 40–50) than astringent persimmons (L* ≈ 65–70), and the type of thickener used had no effect and led to no difference. Furthermore, the cremogenate was harder (F ≈ 20–120 N) when astringent persimmons were used. In astringent cremogenates the thickeners evaluated help in reducing the total phenol content after 3 months of storage in 40% when compared to the control. The heat treatment applied (70 °C, 30 min) did not reverse the astringency, so this type of cremogenate could be a commercial outlet for the waste or surplus of this fruit. In this regard, non‐astringent persimmons with pectin would be recommended for the preparation of cremogenates from this fruit since they were also those that the scored best in the sensory analysis. [ABSTRACT FROM AUTHOR]

The variation of friction coefficient (μ) of model wine and model saliva mixtures with entrainment speed (VR) on simulated oral surfaces was evaluated by oral tribology. Combined with techniques of dynamic light scattering (DLS), atomic force microscopy (AFM), rheometer, and quartz crystal microbalance with dissipation monitoring (QCM‐D), the correlation between characteristics of the model wine and model saliva mixtures (particle size and morphology, suspension viscosity, adsorption film thickness, and viscoelasticity) and the oral lubrication loss was established. The results showed that the higher the concentration of tannin in the model wine, the larger the size of the complexes with the model saliva, and the higher the thickness, viscoelasticity, and roughness of the adsorption film formed, which resulted in the increase of friction coefficient in the boundary lubrication regime. Different from previous results, it is found that the maximum value of the friction coefficient (μmax) in the boundary regime has the best positive correlation with the astringency perception intensity of the model wine accordingly. [ABSTRACT FROM AUTHOR]

The link between salivary composition and sensitivity to astringency as a function of age has still not been established. In this work, we propose the hypothesis that ageing leads to changes in the concentration of salivary proline-rich proteins (PRPs), which alters the astringency perception threshold with age. To test this hypothesis, astringency sensitivity to tannic acid and saliva was assessed in 30 elderly people and 24 young people. Basic PRPs (bPRPs) and glycosylated PRPs (gPRPs) were quantified immunochemically via western blot analysis. The results showed that the amounts of bPRPs and gPRPs were similar between the young and elderly groups. However, a positive correlation between the gPRP amount and astringency threshold was observed only in the young group, while a negative correlation between the bPRP amount and astringency threshold was observed only in the elderly group. This finding suggests differences in the contribution of PRP type to astringency perception as a function of age.

Sensory parameters of food and beverages secured much importance with mounting changes in diet preferences. The taste and flavour of these food groups are largely affected by astringency which in turn influence the sensory experience. Derived from Latin, astringency deals with the sensation of extreme dryness, roughness or puckering involving the secretions of salivary glands. Accountable astringent clusters majorly revolving around the presence of tannins in food trailed by the incidence of salts of multivalent cations like Al, Zn, Cr etc, and dehydrating agents like mineral acids, alcohol etc. To augment the sensory feeling and to broaden the marketing possibilities related to beverages, it is important to accomplish techniques to reduce or control the development of these sensations. De-astringency practices performed in foods can be broadly catalogued into thermal and non-thermal treatments. While the former majorly included hot water, steam and microwave treatment, the latter concentrated mainly on innovative techniques like high hydrostatic pressure, pulsed electric field, thermo-sonication, ultrasonication etc. The effectiveness of these procedures is largely dependent on the mechanisms associated with the development of astringency feelings in foods. Understanding the mechanism underlying astringency sensation is still in a nascent stage and needs more exploration to state the explicit reason behind the process. This review chiefly covers the explanation of astringency, the mechanism involved and the different de-astringency techniques as per the prevailing astringency models.

Persimmon fruits are classified as astringent or non-astringent, depending on the level of astringency the unripe or partially ripe fruit exhibit at the time of harvest. Astringency in persimmon fruit is a sensation caused by tannins present in the flesh that can make the mouth feel dry, cause puckering, numb the tongue, and constrict the throat. Sometimes, it may also impart a bitter taste. The astringency decreases as the fruit ripen until it is no longer present in fully ripe fruit. While consumers typically prefer non-astringent varieties, the cultivation of astringent varieties notably remains common. The purpose of this publication is to introduce consumers, growers, Extension agents, and specialists to postharvest methods for reducing astringency in unripe persimmons, making them more palatable and acceptable for consumption.

This study was performed to explore the differences in the composition of astringent substances in different tissues of fresh lotus seeds and the expression of key enzyme genes involved in the synthesis of astringent compounds. The contents of soluble tannins, insoluble tannins and proanthocyanidins in lotus seed coat, lotus seed pulp without coat and lotus seed plumule were determined. Meanwhile, the activity and gene expression of key enzymes in the tannin synthesis pathway were detected. Sensory evaluation and electronic tongue analysis were performed on lotus seed samples. The data obtained was analyzed by orthogonal partial least squares discriminant analysis (OPLS-DA) and correlation analysis. Results showed that the major substance contributing to the astringency of lotus seeds was soluble tannins. Tannins had a positive effect on its excellent flavor at the waxy ripeness stage. Anthocyanin reductase was a key enzyme affecting the astringency intensity of lotus seeds. SnANR9 played a role in regulating the astringency of different tissues of lotus seeds.

With the wide application of quaternion, the solution of large quaternion structured matrix equations has become an important topic in scientific computing. Based on the new positive definite and skew-self-conjugate splitting iteration(NPSS), two new mixed-parameter splitting iteration schemes were constructed for the quaternion sub-positive definite system AX = B by introducing the two-parameter and relaxation acceleration techniques. That is, asymmetric new positive definite and skew-self-conjugate splitting ( ANPSS), successive over relaxation asymmetric new positive definite and skew-self-conjugate splitting ( SANPSS), and the convergence of these two iterations was proved by using the eigenvalue theory of quaternion matrix, and the range of relevant parameters was given. In addition, the complex representation method of quaternion matrix was used to realize the numerical solution of the system in MATLAB environment. Numerical examples show that the flexible selection of multiple parameters shows that the proposed mixed parameter splitting iteration has higher convergence efficiency than NPSS iteration. [ABSTRACT FROM AUTHOR]

This study aimed to reduce the bitterness and astringency properties of autumn green tea using different yellowing and drying treatments. The results showed that as the yellowing temperature increased, the contents of tea polyphenols, gallated catechins, flavonol glycosides, and bitter amino acids decreased, while the content of soluble sugar and flavonols increased. The tea sample (YEL35 °C) subjected to yellowing treatment at 35 °C exhibited weak bitterness and astringency intensities and a relatively low content of flavonol glycosides. As the drying temperature increased, the content of gallated catechins decreased. In addition, the tea sample (DRY75 °C) subjected to drying treatment at 75 °C exhibited weak bitterness and astringency intensities, the highest contents of umami amino acids and Thea, and a relatively low content of gallated catechins. Multivariate statistical analysis revealed that vitexin-2-O-rhamnoside, pferol-3-O-rutinoside, myricetin-3-O-galactoside, and quercetin-3-O-glucoside played an important role in the astringency property of the tea. In addition, Asn, Thr, Pro, and Met were positively correlated with umami. Hence, the quality of autumn green tea was improved under optimal yellowing and drying temperatures of 35 and 75 °C, respectively. [ABSTRACT FROM AUTHOR]

BACKGROUND: Historically, the effect of wine grape shading on flavonoids has investigated the impact of light incidence on proanthocyanidin (PA), flavonol, or anthocyanin concentration. In addition to concentration, the current experiment was designed to look at changes in PA composition, size and tannin activity through ripening. Tannin activity is a methodology for assessing the impact of structure and size on the affinity of tannin towards a hydrophobic surface and is considered to be a proxy for predicted astringency descriptive quality. In 2016 a shade cloth study was imposed on Cabernet Sauvignon on Mt Veeder, within the larger Napa Valley viticultural area. A control, which was unshaded, and two treatments consisting of 40% and 80% shade were applied at the onset of veraison. RESULTS: Results showed significant differences in the composition and concentration of anthocyanins throughout ripening. Compositional differences in PA were also observed, where shaded treatments had a significantly higher proportion of galloylated subunits. The molecular mass of the extracted tannin was significantly lower in the unshaded control than in the 80% shade treatment. These factors led to a lower measured tannin activity in extracts from exposed fruit. CONCLUSION: This work suggests that manipulation of canopy architecture, such as artificial shading, leads to changes in berry pigmentation, tannin composition and activity. These results show that the astringency and mouthfeel characteristics of a wine may be altered by vineyard management practices. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: Tannin content and postharvest quality characteristics of persimmon fruit are often determined by the destructive analysis that consumes time, does not allow the acquisition of data from the same fruit continuously, and requires expensive high-performance equipment. This research was done to investigate the potential for non-destructive estimation of astringency and quality parameters in persimmon fruit based on visible/near-infrared (VNIR) spectra. Methods: VNIR spectra readings, the reference tannin content, and quality parameters were measured from fruits of “Cheongdo-Bansi” and “Daebong” persimmon cultivars at harvest and throughout the ripening/deastringency period. The spectra readings from half of the total fruit were utilized for the calibration set, while the other half readings were used for the prediction set. To develop models correlating the spectra data to the measured reference parameters data, the partial least square regression (PLSR) method was utilized. Results and discussion: In the case of ‘Daebong’, the coefficients of determination (R2 ) between VNIR spectra and the actual measured values of TSS, firmness, simple sugars, and tannin content were (0.95, 0.94, 0.96, and 0.96) and (0.93, 0.89, 0.96, and 0.93), for the calibration and prediction sets, respectively. Similarly, the R2 -values of (0.86, 0.93, 0.79, and 0.81) and (0.83, 0.91, 0.75, and 0.75) were recorded in ‘Cheongdo-Bansi’ for the calibration and prediction sets, respectively. Additionally, the acquired data were divided into two sets in a 3:1 ratio to develop predictive models and to validate the models in multiple regressions. PLSR models were developed in multiple regression to estimate the tannin content of both cultivars from firmness and simple sugars with R2 -values of 0.83 and 0.79 in ‘CheongdoBansi’ for the calibration and prediction sets, respectively, whereas, R2 -values of 0.80 and 0.84 were recorded in ‘Daebong’ for the calibration and prediction sets, respectively. The overall findings of this study showed the possibility of using VNIR spectra for the prediction of postharvest quality and tannin contents from intact persimmon fruit with quick, chemical-free, and low-cost assessment methods. Also, the multiple regression using physicochemical parameters could fairly predict the tannin content in persimmon fruit though destructively but save time and low-cost. [ABSTRACT FROM AUTHOR]

Abstract The objective of this work was characterizing persimmons of the 'Giombo' and 'Rama Forte' cultivars harvested at different ripening stages in the Brazilian semiarid. Fruits were harvested at three ripening stages – green, semi-ripe and ripe – then evaluated for the following characteristics: fruit weight and diameter, skin and pulp color, fruit firmness, pulp pH, soluble solids content, titratable acidity, SSC/TA ratio, total soluble sugars, reducing sugars, astringency index, and the contents of tannin, vitamin C, carotenoid, β-carotene, and total extractable polyphenols. Also, total antioxidant activity by the DPPH and ABTS methods and pectin methylesterase, and polygalacturonase enzyme activities were evaluated. Two experiments were carried out in a completely randomized design, one for each cultivar, with treatments consisting of different stages of maturation, with five replications of three fruits each. Data were submitted to analysis of variance and the differences between the means were compared using the Tukey test at 5% probability. Fruit firmness and soluble solids content did not vary between maturation stages for any of the cultivars. However, the skin color index increased with advancing maturation for both 'Giombo' and 'Rama Forte'. The astringency index, the content of total extractable polyphenols, soluble tannins and the antioxidant capacity were lower in fruits harvested at the ripe stage, for both cultivars. It can be concluded that persimmons of the 'Giombo' and 'Rama Forte' cultivars present better physicochemical quality characteristics when harvested when ripe, with a totally yellow skin.

Astringency is not considered one of the modern gustatory tastes. The understanding of astringency perception has evolved considerably over the past eighty years, but the exact mechanism is still undefined. This review aims to identify the current theory of astringency perception in the context of red wine. While astringency perception is a complicated mechanism that is not yet well understood, much research has focused on it. The studies discussed up to now have been done using red wine or wine-derived polyphenols. In a red wine context, astringency is driven by polyphenol concentration, galloylation and degree of polymerisation. Compounds that do not bind protein but are still strong astringent agonists are present in red wine. Among them, the role of polysaccharides and oligosaccharides is not clear, as these compounds are difficult to purify in quantities large enough for use in sensory studies. The literature strongly points to astringency being a compound perception. There is a stage of early protein binding, possibly as a “neutralising” effect for small amounts of dietary tannins with little actual perception, building into a more pronounced effect as tannin concentrations increase. A loss of lubrication in the oral cavity might announce the overpowering salivary protein capacity resulting from tannin concentrations, with direct detection of some astringent compounds once protein in the salivary fluid and the salivary pellicle are depleted.

IntroductionTannin content and postharvest quality characteristics of persimmon fruit are often determined by the destructive analysis that consumes time, does not allow the acquisition of data from the same fruit continuously, and requires expensive high-performance equipment. This research was done to investigate the potential for non-destructive estimation of astringency and quality parameters in persimmon fruit based on visible/near-infrared (VNIR) spectra.MethodsVNIR spectra readings, the reference tannin content, and quality parameters were measured from fruits of “Cheongdo-Bansi” and “Daebong” persimmon cultivars at harvest and throughout the ripening/deastringency period. The spectra readings from half of the total fruit were utilized for the calibration set, while the other half readings were used for the prediction set. To develop models correlating the spectra data to the measured reference parameters data, the partial least square regression (PLSR) method was utilized.Results and discussionIn the case of ‘Daebong’, the coefficients of determination (R2) between VNIR spectra and the actual measured values of TSS, firmness, simple sugars, and tannin content were (0.95, 0.94, 0.96, and 0.96) and (0.93, 0.89, 0.96, and 0.93), for the calibration and prediction sets, respectively. Similarly, the R2-values of (0.86, 0.93, 0.79, and 0.81) and (0.83, 0.91, 0.75, and 0.75) were recorded in ‘Cheongdo-Bansi’ for the calibration and prediction sets, respectively. Additionally, the acquired data were divided into two sets in a 3:1 ratio to develop predictive models and to validate the models in multiple regressions. PLSR models were developed in multiple regression to estimate the tannin content of both cultivars from firmness and simple sugars with R2-values of 0.83 and 0.79 in ‘Cheongdo-Bansi’ for the calibration and prediction sets, respectively, whereas, R2-values of 0.80 and 0.84 were recorded in ‘Daebong’ for the calibration and prediction sets, respectively. The overall findings of this study showed the possibility of using VNIR spectra for the prediction of postharvest quality and tannin contents from intact persimmon fruit with quick, chemical-free, and low-cost assessment methods. Also, the multiple regression using physicochemical parameters could fairly predict the tannin content in persimmon fruit though destructively but save time and low-cost.

The commercial persimmon fruit (Diospyros kaki) is a seasonal fruit and it contains various nutrients such ascarbohydrates,vitamins, fiber, minerals, phenolic compounds (ferulic acid, p-Coumaric acid, and gallic acid) and carotenoids (β-cryptoxanthin, lycopene, β-carotene, zeaxanthin, and lutein). This current review is an effort to sum up information regarding persimmon fruit's nutrient profile, bioactive potential, pharmacological potential, and its utilization in industry. Accordingly, the bioactive components such as p-Coumaric acid, epigallocatechin gallate, proanthocyanins, flavonoids, etc. and their extraction techniques such as high hydrostatic pressure (HHP), microwave-assisted extraction, and ultrasonic-assisted extraction are also highlighted. Further this review also describe the evidence based various pharmacological application of fruit and its bioactive components which have scavenging effect on active oxygen free radicals (flavonoids), prevents oxidative stress-related illnesses (p-Coumaric), promote neural degeneration and karyopyknosis in cells (tannin), may assist with hyperlipidemia and diabetes (proanthocyanidins). Overall persimmon and its components application in multiple products in various forms in the food sector can open up new avenues for its utilization, enhancing the natural flavour and bioactive components while also improving health.

Proanthocyanidins (PAs) are specialized metabolites that influence persimmon fruit quality. Normal astringent (A)‐type and non‐astringent (NA)‐type mutants show significant variation in PA accumulation, but the influencing mechanism remains unclear. In this study, among the six identified DTXs/MATEs proteins associated with PA accumulation, we observed that allelic variation and preferential transport by DkDTX5/MATE5 induced variation in PA accumulation for A‐type and NA‐type fruit. The expression pattern of DkDTX5/MATE5 was correlated with PA accumulation in NA‐type fruit. Upregulation and downregulation of DkDTX5/MATE5 promoted and inhibited PA accumulation, respectively, in the NA‐type fruit. Interestingly, transporter assays of Xenopus laevis oocytes indicated that DkDTX5/MATE5 preferentially transported the PA precursors catechin, epicatechin, and epicatechin gallate, resulting in their increased ratios relative to the total PAs, which was the main source of variation in PA accumulation between the A‐type and NA‐type. The allele lacking Ser‐84 in DkDTX5/MATE5 was identified as a dominantly expressed gene in the A‐type and lost its transport function. Site‐directed mutagenesis revealed that DkDTX5/MATE5 binds to PA precursors via Ser‐84. These findings clarify the association between the transporter function of DkDTX5/MATE5 and PA variation, and can contribute to the breeding of new cultivars with improved fruit quality. [ABSTRACT FROM AUTHOR]

Wine astringency is a very complex sensation whose complete mechanism has not been entirely described. Not only salivary proline-rich proteins (PRPs) are involved in its development; salivary mucins can also play an important role. On the other hand, it has been described that anthocyanins can interact with PRPs, but there is no information about their potential role on the interactions with mucins. In this work, the molecular interactions between salivary mucins (M) and different wine phenolic compounds, such as catechin (C), epicatechin (E) and quercetin 3-β-glucopyranoside (QG), as well as the effect of the anthocyanin malvidin 3-O-glucoside (Mv) on the interactions with mucins, were assessed by isothermal titration calorimetry (ITC). Results showed that the interaction between anthocyanin and mucins is stronger than that of both flavanols analyzed, since the affinity constant values were 10 times higher for anthocyanin than for catechin, the only flavanol showing interaction in binary assay. Moreover, at the concentration at which polyphenols are usually found in wine, flavonols seem not to be involved in the interactions with mucins. These results showed, for the first time, the importance of wine anthocyanins in the mechanisms of astringency involving high-molecular-weight salivary proteins like mucins. [ABSTRACT FROM AUTHOR]

Frequent polyploidization events in plants have led to the establishment of many lineage-specific traits representing each species. Little is known about the genetic bases for these specific traits in polyploids, presumably due to plant genomic complexity and their difficulties in applying genetic approaches. Hexaploid Oriental persimmon (Diospyros kaki) has evolved specific fruit characteristics, including wide variations in fruit shapes and astringency. In this study, using whole-genome diploidized/quantitative genotypes from ddRAD-Seq data of 173 persimmon cultivars, we examined their population structures and potential correlations between their structural transitions and variations in nine fruit traits. The population structures of persimmon cultivars were highly randomized and not substantially correlated with the representative fruit traits focused on in this study, except for fruit astringency. With genome-wide association analytic tools considering polyploid alleles, we identified the loci associated with the nine fruit traits; we mainly focused on fruit-shape variations, which have been numerically characterized by principal component analysis of elliptic Fourier descriptors. The genomic regions that putatively underwent selective sweep exhibited no overlap with the loci associated with these persimmon-specific fruit traits. These insights will contribute to understanding the genetic mechanisms by which fruit traits are independently established, possibly due to polyploidization events. [ABSTRACT FROM AUTHOR]

[Display omitted] Texture and mouthfeel are central to the sensory enjoyment of food and beverages. Yet our incomplete understanding of how food boluses are transformed in the mouth limits our texture prediction ability. As well as thin film tribology, the interaction of food colloids with the oral tissue and salivary biofilms plays a key role in texture perception via mechanoreceptors in the papillae. In this study we describe the development of an oral microscope capable of quantitative characterization of the inactions of food colloids with papillae and their concurrent saliva biofilm. We also highlight how the oral microscope revealed key microstructural drivers of several topical phenomena (oral residue formation, coalescence in-mouth, grittiness of protein aggregates and finally microstructural origin of polyphenol astringency) in the domain of texture creation. The coupling of a fluorescent food grade dye with image analysis enabled specific and quantitative determination of the microstructural changes in mouth. Emulsions either underwent no aggregation, small aggregation, or extensive aggregation depending on whether their surface charge facilitated complexation with the saliva biofilm. Quite surprisingly cationic gelatin emulsions that were already aggregated with saliva in mouth underwent coalescence if subsequently exposed to tea polyphenols (EGCG). Large protein aggregates were found to aggregate with the saliva coated papillae, increasing their size tenfold and possibly explaining why there are perceived as gritty. An exciting observation was the oral microstructural changes that occurred upon exposure to tea polyphenols (EGCG). Filiform papillae shrunk, and the saliva biofilm was seen to precipitate/collapse, exposing a very rough tissue surface. These tentative early steps are the first in vivo microstructural insights into the different food oral transformations that are drivers of key texture sensation. [ABSTRACT FROM AUTHOR]

Excessive galloylated flavanols not only cause instability in the wine but also lead to unbalanced astringency. Although clarification agents are always used to precipitate unstable tannins in wine, the non-specific adsorption of tannins results in the failure to precisely regulate the tannin composition of the wine. In this work, molecularly imprinted polymers (MIPs) with template molecules of galloylated flavanols were designed to specifically adsorb gallotannins to reduce wine astringency. The results showed that the "pores" on the surface of the MIPs are the structural basis for the specific adsorption of the target substances, and the adsorption process is a chemically driven single-molecule layer adsorption. Moreover, in the mono/oligomeric gallotannin-rich model solution, the adsorption of gallotannins by I-MIPs prepared as single template molecules reached 71.0%, and the adsorption capacity of MIPs for monomeric gallotannins was about 6.0 times higher than polymeric gallotannins. Given the lack of technology for the targeted adsorption of tannins from wine, this work explored the targeted modulation of wine astringency by using molecular imprinting techniques. [ABSTRACT FROM AUTHOR]

Wine tastes better with age because of a complex chemical reaction among sugars, acids, and phenolic compounds. This study investigates if applying ultrasonic waves to wine would significantly reduce its perceived astringency levels. Ultrasonic (US) waves were applied to samples of a young Cabernet Sauvignon using a 24 kHz ultrasonic processor and sonotrode probe by varying time,, and amplitude at three levels. To objectively assess the relationship between the US waves and astringency, physical and chemical analysis was carried out that confirmed the underlying assumptions. While the pH of the treated samples decreased slightly, there was no change in color (Hunter CIE Color L*a*b*). Total Phenolic Content (TPC), Total Anthocyanin Content (TAC), and Tannin Concentration (TC) were significantly different (p ≤.05) among all samples, indicating the impact of sonication on astringency causing components. Additionally, Fourier Transform Near Infrared (FT-NIR) spectroscopy confirmed that there were notable changes in the spectra, attributed to tannins, of wine after the application of sonication in comparison to untreated wine samples. The perception of astringent flavor was evaluated by (i) expert wine tasters and (ii) untrained panelists (n = 60) who were able to clearly distinguish between treated and untreated samples (p ≤.05) and preferred sonicated samples (180 sec, 100% amplitude) over the control samples, supporting the hypothesis that sonication reduces the astringency of red wine. [ABSTRACT FROM AUTHOR]

Astringency has an important impact on the taste quality of tea infusion, a process which occurs when polyphenols complex with salivary proteins to form an impermeable membrane. (-)-Epigallocatechin gallate (EGCG) is the main astringent compound found in green tea and mucin is the main protein present in saliva. Determining the turbidity of EGCG–mucin mixtures is an effective method to quantify the astringency intensity of EGCG solutions. In this study, the effects of taste-related, substances present during green tea infusion, on the turbidity of EGCG–mucin mixtures was investigated under the reacting conditions of a pH value of 5.0, at 37 °C, and for 30 min. The results showed that epicatechins, caffeic acid, chlorogenic acid, and gallic acid reduced the turbidity of EGCG–mucin mixtures, while rutin increased turbidity. Metal ions increased the turbidity of EGCG–mucin mixtures. These can be arranged by effectiveness as Al3+ > K+ > Mg2+ > Ca2+. Caffeine, theanine, and sodium glutamate all decreased the turbidity values of EGCG–mucin mixtures, but sucrose had a weak effect. Further experiments confirmed that the turbidity of green tea infusion–mucin mixture indicated the astringent intensity of green tea infusion, and that the turbidity was significantly correlated with the contents of tea polyphenols and EGCG.

Recent studies have demonstrated that the interaction of dietary constituents with taste and olfactory receptors and nociceptors expressed in the oral cavity, nasal cavity and gastrointestinal tract regulate homeostasis through activation of the neuroendocrine system. Polyphenols, of which 8000 have been identified to date, represent the greatest diversity of secondary metabolites in plants, most of which are bitter and some of them astringent. Epidemiological studies have shown that polyphenol intake contributes to maintaining and improving cardiovascular, cognitive and sensory health. However, because polyphenols have very low bioavailability, the mechanisms of their beneficial effects are unknown. In this review, we focused on the taste of polyphenols from the perspective of sensory nutrition, summarized the results of previous studies on their relationship with bioregulation and discussed their future potential.

• Oral astringent stimulations activated the insula of human brains. • The cerebellum, frontal and temporal cortices might play a role in taste recognition. • Brain responses to "taste" stimulations were relatively stable over time. Taste and oral somatosensation are intimately related to each other from peripheral receptors to the central nervous system. Oral astringent sensation is thought to contain both gustatory and somatosensory components. In the present study, we compared the cerebral response to an astringent stimulus (tannin), with the response to one typical taste stimulus (sweet – sucrose) and one typical somatosensory stimulus (pungent – capsaicin) using functional magnetic resonance imaging (fMRI) of 24 healthy subjects. Three distributed brain sub-regions responded significantly different to the three types of oral stimulations: lobule IX of the cerebellar hemisphere, right dorsolateral superior frontal gyrus, and left middle temporal gyrus. This suggests that these regions play a major role in the discrimination of astringency, taste, and pungency. [ABSTRACT FROM AUTHOR]

Grenache wines from the Central Coast of California were subjected to different alcoholic fermentation temperature regimes (Cold, Cold/Hot, Hot) and cap management protocols, namely, punch down (PD), or no punch down (No PD), to determine the effect of these practices on the color, aroma, and the retronasal and mouthfeel sensory characteristics of the resulting wines. Descriptive analysis (n = 8, line scale rating 0–15) results indicated that the combination of a hot fermentation temperature and no punch downs led to a significantly higher intensity in perceived color saturation (7.89) and purple hue (8.62). A two-way analysis of variance (ANOVA) showed that cap management was significantly more impactful on the perception of orthonasal aromas than fermentation temperature. The reduction aroma was significantly higher in No PD wines (5.02) compared to PD wines (3.50), while rose and hot aromas had significantly higher intensity perception for PD wines (5.18, 6.80) than for No PD wines (6.80, 6.14). Conversely, analysis of selected volatile compounds indicated that fermentation temperature was more impactful than cap management regime. Cold/Hot wines had higher concentrations of important esters such as ethyl hexanoate (650 µg/L) and isoamyl acetate (992 µg/L). Cold wines had a higher concentration of β-damascenone (0.719 µg/L). TCATA evaluation (n = 8) indicated that Cold/Hot PD wines had a significantly higher citation proportion of fruit flavor (1.0) and velvet astringency perception (0.80) without significant reduction flavors. Finally, the present study represents a contribution with the main volatile compounds (e.g., β-damascenone and esters in the Cold and Cold/Hot fermented wines, respectively; hexanol in PD wines, which may be potentially responsible for a hot mouthfeel), and sensory characteristics (red fruit, tropical fruit, white pepper, and rose) of Grenache wines grown in the Mediterranean climate of the Central Coast of California. [ABSTRACT FROM AUTHOR]

Objective: To review the efficacy and safety of tannin albuminate and ethacridine lactate monohydrate in the treatment and prevention of diarrhea. Design: Narrative review. Data sources: A systematic literature search was conducted in MEDLINE and Embase from inception to September 2022. The search was restricted to English and German language publications. Eligibility criteria for selecting studies: Randomized controlled trials, non-interventional studies, and meta-analyses assessing tannin and/or ethacridine for the treatment or prevention of diarrhea. Results: Of 366 titles identified, a total of 13 studies were included in this review. Five randomized controlled trials and four noninterventional trials demonstrate the efficacy and safety of the fixed combination of tannin albuminate and ethacridine lactate monohydrate in treating acute diarrhea and preventing traveler's diarrhea. The fixed combination reduced acute diarrhea duration by improving stool frequency, consistency, and weight and reduced the risk of traveler's diarrhea. Two pilot studies indicate efficacy in chronic diarrhea. Safety and tolerability were very good in all included studies. Two meta-analyses investigated the efficacy of gelatin tannate in children with acute gastroenteritis. Conclusion: The efficacy and safety of tannin albuminate and ethacridine lactate monohydrate for the treatment of acute diarrhea and the prevention of traveler's diarrhea are proven in randomized controlled trials. Several noninterventional studies substantiate the real-world effectiveness and tolerability of the fixed combination. Both active ingredients combine antidiarrheal, antimicrobial, mucosal protection, and spasmolytic properties. However, existing clinical data should be updated with larger, well-designed, placebo-controlled trials in adult and pediatric patient populations. [ABSTRACT FROM AUTHOR]

Despite the many advantages of pulses, they are characterised by off-flavours that limit their consumption. Off-notes, bitterness and astringency contribute to negative perceptions of pulses. Several hypotheses have assumed that non-volatile compounds, including saponins, phenolic compounds, and alkaloids, are responsible for pulse bitterness and astringency. This review aims to provide an overview highlighting the non-volatile compounds identified in pulses and their bitter and/or astringent characteristics to suggest their potential involvement in pulse off-flavours. Sensorial analyses are mainly used to describe the bitterness and astringency of molecules. However, in vitro cellular assays have shown the activation of bitter taste receptors by many phenolic compounds, suggesting their potential involvement in pulse bitterness. A better knowledge of the non-volatile compounds involved in the off-flavours should enable the creation of efficient strategies to limit their impact on overall perception and increase consumer acceptability. [ABSTRACT FROM AUTHOR]

Beer is one of the most consumed beverages worldwide with unique organoleptic properties. Bitterness and astringency are well-known key features and, when perceived with high intensity, could lead to beer rejection. Most studies on beer astringency and bitterness use sensory assays and fail to study the molecular events that occur inside the oral cavity responsible for those perceptions. This work focused on deepening this knowledge based on the interaction of salivary proteins (SP) and beer phenolic compounds (PCs) and their effect toward these two sensory attributes. The astringency and bitterness of four different beers were assessed by a sensory panel and were coupled to the study of the SP changes and PC profile characterization of beers. The human SP content was measured before (basal) and after each beer intake using HPLC analysis. The beers' PC content and profile were determined using Folin–Ciocalteu and LC-MS spectrometry, respectively. The results revealed a positive correlation between PCs and astringency and bitterness and a negative correlation between SP changes and these taste modalities. Overall, the results revealed that beers with higher PC content (AAL and IPA) are more astringent and bitter than beers with a lower PC content (HL and SBO). The correlation results suggested that an increase in whole SP content, under stimulation, should decrease astringency and bitterness perception. No correlation was found between the changes in specific families of SP and astringency and bitterness perception. [ABSTRACT FROM AUTHOR]

BACKGROUND: Oenological tannins are commercial natural products extracted from different botanical sources, which were widely reported as prominent contributors to wine quality. Research on wine quality affected by tannins extracts promoted the development of new oenological products with low cost and high accessibility. In the present study, the structure and concentration of tannin in polyphenol extracts, as well as their correlation with astringency and the color of model wine, was investigated by UV spectrophotometer, HPLC, fluorescence quenching, sodium dodecylsulfate-polyacrylamide gel electrophoresis, colorimeter and sensory evaluation. RESULTS: Resource extracts from 16 of 44 plants were screened as wine oenological tannins, according to the total polyphenol and total flavanol, as well as the intensity of astringency and bitterness. Polyphenols extracted from grape seeds and green tea were more effective in increasing the wine astringency compared to other plant tannins. CONCLUSION: Total flavanol content and tannin activity showed a strong correlation with wine astringency. Condensed tannins with mean degree of polymerization also exhibited strong color stability, and the concentrations of (-)-epigallocatechin were associated with the a* value, a negative qualitative factor for wine color. The present study provides new clues regarding the development of low-cost and highly accessible sources of polyphenol extracts and lays a theoretical foundation for the development of the oenological product. [ABSTRACT FROM AUTHOR]

Taste dysfunctions may occur, for example, after viral infection, surgery, medications, or with age. In clinical practice, it is important to assess patients' taste function with rapidity and reliability. This study aimed to develop a test that assesses human gustatory sensitivity together with somatosensory functions of astringency and spiciness. A total of 154 healthy subjects and 51 patients with chemosensory dysfunction rated their gustatory sensitivity. They underwent a whole-mouth identification test of 12 filter-paper strips impregnated with low and high concentrations of sweet, sour, salty, bitter (sucrose, citric acid, NaCl, quinine), astringency (tannin), and spiciness (capsaicin). The percentage of correct identifications for high-concentrated sweet and sour, and for low-concentrated salty, bitter and spicy was lower in patients as compared with healthy participants. Interestingly, a lower identification in patients for both astringent concentrations was found. Based on the results, we proposed the Seven-iTT to assess chemo/somatosensory function, with a cut-off of 6 out of 7. The test score discriminated patients from healthy controls and showed gender differences among healthy controls. This quantitative test seems to be suitable for routine clinical assessment of gustatory and trigeminal function. It also provides new evidence on the mutual interaction between the two sensory systems. [ABSTRACT FROM AUTHOR]

The chemical mechanism of the acid cleavage of proanthocyanidins (PAs) has been known for decades but has yet to be optimized. Therefore, we optimized this process in Byrsonima crassifolia, Euterpe oleracea and Inga edulis extracts using the response surface methodology and assessed the effect of hydrochloric acid concentration (0.3–3.7 N), time (39–291 min), and temperature (56–98 °C) on the following response variables: PAs reduction, astringency reduction, antioxidant capacity/total polyphenols (TEAC/TP) ratio, and cyanidin content. The response variables were maximized when cleavage was performed with 3 N HCl at 88 °C for 165 min. Under these conditions, the mean PAs value and astringency in the three extracts decreased by 91% and 75%, respectively, the TEAC/TP ratio remained unchanged after treatment (p > 0.05), and the increase in cyanidin confirmed the occurrence of cleavage. Thus, the results suggest that acid cleavage efficiently minimizes undesirable technological PAs characteristics, expanding the industrial applications. [ABSTRACT FROM AUTHOR]

The Italian wine appellations system is organized in hundreds of origin wines, with unique characteristics that are protected with many denominations of origin. The aim of this work was to analyze and compare the proanthocyanin profile of 12 single-cultivar and single-vintage Italian red wine groups (Aglianico from Campania, Cannonau from Sardinia, Corvina from Veneto, Montepulciano from Abruzzo, Nebbiolo from Piedmont, Nerello Mascalese from Sicily, Primitivo from Apulia, Raboso Piave from Veneto, Sagrantino from Umbria, Sangiovese from Tuscany and Romagna, and Teroldego from Trentino), each one produced in their terroirs under ad hoc legal frameworks to guarantee their quality and origin. All wines were analyzed with a protocol that combined the phloroglucinolysis reaction with an LC-MS/MS instrument. The results underlined Sagrantino wines as the richest in proanthocyanins. Sangiovese, Montepulciano, Nerello, and Teroldego were the richest in B-ring trihydroxylated flavan-3-ols, and especially Nerello was the richest in prodelphinidins. Cannonau, Raboso Piave, Nerello, and Corvina were characterized by C-ring trans conformation flavan-3-ols. Nebbiolo and Corvina had high percentages of galloylated flavan-3-ols. Aglianico and Primitivo had the lowest percentages of B-ring trihydroxylated and C-ring trans conformation flavan-3-ols. This information should be useful in better understanding the Italian red wines and valorize them. [ABSTRACT FROM AUTHOR]

The astringency of wine has always been a hot topic in wine research, and a variety of research methods have evolved from it. In the astringency research system, there are various qualitative and quantitative methods related to the astringency substances in wine, but the lack of discussion on the applicability of the method has caused researchers to misuse the method when using the method. In addition, the literature on the sense of astringency mostly introduces the research results of the sense of astringency, and lacks the interpretation of the system. On the basis of summarizing the polyphenols in wine, this article clarifies the analysis method of astringency, and further summaries the research system of astringency, and discusses the future research direction of astringency in wine.

Assessment of taste and somatosensory perception in clinical practice lacks fast tests that are validated and reliable. Recently, a 12-item identification test for taste and oral trigeminal perception, and its shorter version, the Seven-iTT, was developed. The objectives of this study were to evaluate its test-retest reliability and establish normative data. Two-hundred participants (120 women, 80 men) with a good sense of taste performed a whole-mouth identification test using 12 filter-paper strips impregnated with low and high concentrations of sweet, sour, salty, bitter, astringency, and spiciness. Fifty of them repeated the task, with a median interval of 122 days from the first visit. Test-retest reliability was determined using Spearman correlation and the Bland–Altman plot method. There was a significant correlation in identification score between the first and the second session for both versions of the test (r ≥ 0.28; p ≤ 0.048). The Bland–Altman plot reflected a good congruence between the results of the two sessions. Additionally, frequencies of correct identification were consistent between sessions, with women outperforming men (p = 0.005). Hypogeusia was established at Seven-iTT score of 3 of less. The identification test combines taste and somatosensory perception, thus creating a more detailed diagnosis tool. Scores were correlated with self-rated taste perception. The present results confirmed the applicability of Seven-iTT for a reliable, fast evaluation of taste and somatosensory perception in the general population, that can be extended to clinical practice. • We examined the test-retest reliability of the Seven-iTT and its extended version. • Normative values are presented for this test; a cut-off is set at 3. • The test confirmed gender and age differences in taste identification. • The identification test is a useful and detailed diagnostic tool. [ABSTRACT FROM AUTHOR]

Drying persimmon pulp causes an increase in astringency, which is a great concern for persimmon manufacturers. This research investigates the increment in astringency observed during three drying technologies, freeze, vacuum and hot air drying, respectively, and proposes two mitigation pretreatments. The phenols in persimmon samples were correlated with their astringent level measured by tannin content, mean degree of polymerization (mDP) and degree of galloylation (DG). The astringency of fresh persimmon pulp increased four times after freeze drying, which is the least compared to hot air and vacuum drying. However, pH adjustment and pectinase hydrolysis can effectively mitigate the astringent taste. The best pre-treatment was pectinase hydrolysis since it decreased the mDP to 4.7 and DG to 13 %, similar to the level of fresh pulp. The acidic pH treatment (pH=2) can also significantly decrease the astringent level, however, the taste perception also changed dramatically. An HPLC-MS-DAD analysis has identified and quantified the phenol profile of dried persimmon, and the concentration of small molecular weight phenols was negatively correlated to the tannin content, thus astringent level. A further multivariate analysis including tannin concentration, phenols quantification and taste simulation by e-tongue confirmed that pectinase pretreatment has the least increment in astringency and similar taste perception. [Display omitted] • The re-astringency of persimmon pulp during drying was observed and characterized. • The efficiency of pH and enzyme treatments to mitigate re-astringency was evaluated. • Gallic acid and its derivatives were the most important compounds in persimmon. • A high correlation was observed between tannin content and oral perception. • Pretreatment with pectinase is able to mitigate re-astringency significantly. [ABSTRACT FROM AUTHOR]