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Foods (Basel, Switzerland) Sep 2023Tea is the most popular and widely consumed beverage worldwide, especially black tea. Summer tea has a bitter and astringent taste and low aroma compared to spring tea...
Tea is the most popular and widely consumed beverage worldwide, especially black tea. Summer tea has a bitter and astringent taste and low aroma compared to spring tea due to the higher content of polyphenols and lower content of amino acids. Microbial fermentation is routinely used to improve the flavor of various foods. This study analyzed the relationship between the quality of black tea, metabolic characteristics, and microbial communities after microbial stuck fermentation in summer black tea. Stuck fermentation decreased the bitterness, astringency sourness, and freshness, and increased the sweetness, mellowness, and smoothness of summer black tea. The aroma also changed from sweet and floral to fungal, with a significant improvement in overall quality. Metabolomics analysis revealed significant changes in 551 non-volatile and 345 volatile metabolites after fermentation. The contents of compounds with bitter and astringent taste were decreased. Sweet flavor saccharides and aromatic lipids, and acetophenone and isophorone that impart fungal aroma showed a marked increase. These changes are the result of microbial activities, especially the secretion of extracellular enzymes. , , and contribute to the reduction of bitterness and astringency in summer black teas after stuck fermentation, and Paenibacillus and contribute positively to sweetness. In addition, Aspergillus was associated with the formation of fungal aroma. In summary, our research will provide a suitable method for the improvement of tea quality and utilization of summer tea, as well as provide a reference for innovation and improvement in the food industry.
PubMed: 37761123
DOI: 10.3390/foods12183414 -
Foods (Basel, Switzerland) Sep 2023Wine 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...
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--glucopyranoside (QG), as well as the effect of the anthocyanin malvidin 3--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.
PubMed: 37835279
DOI: 10.3390/foods12193623 -
BMC Complementary and Alternative... Sep 2019Natural products play a significant role in human health in relation to the prevention and treatment of inflammatory conditions. One of the plants with great medicinal...
BACKGROUND
Natural products play a significant role in human health in relation to the prevention and treatment of inflammatory conditions. One of the plants with great medicinal potentials is Diospyros kaki which is mainly cultivated in Asian countries including Korea, Japan, and China. Astringent D. kaki is a wild species with an astringent taste until they are Ripened. kaki calyx is a traditional Korean medicine (TKM) made from the stalks of astringent D. kaki and is used in treating bed-wetting, vomiting, and hiccupping. The present study was designed to investigate the potential anti-inflammatory activities of astringent D. kaki stalks based on cultivar types and stages of maturity.
METHODS
The anti-inflammatory effects of the stalk extracts of local astringent D. kaki cultivar species were evaluated on RAW 264.7 cells. Cell viability was measured using a Cell Counting Kit-8 (CCK8) method. The anti-inflammatory effects were determined by measuring the nitric oxide (NO) concentration of the supernatant. Cellular signaling pathways were determined by quantitative polymerase chain reactions of inducible nitric oxide synthase (iNOS). Protein expression of iNOS and phospho-p65 was determined using western blot, and the nuclear localization of p65 was determined using confocal imaging in RAW 264.7 cells.
RESULTS
We found that the stage 1 (8-9 month) samples all showed a high percentage of tannic acid content and Gojongsi (Hamyang) stalks had the highest content. The stage 1 samples also showed the highest inhibition of NO production. Decreases in the expression of iNOS and phosphorylated p65, and in the nuclear localization of p65, were dose-dependent. All the extracts were nontoxic under 100 μg/ml concentration.
CONCLUSION
This study provides insight into the changes in tannic acid content in astringent D. kaki and their anti-inflammatory effects, in relation to their stage of maturity. These results are expected to be useful in the verification of the efficacy of oriental medicine and the timing of proper harvest for medical use.
Topics: Animals; Anti-Inflammatory Agents; Diospyros; Humans; Macrophages; Mice; Nitric Oxide; Nitric Oxide Synthase Type II; Plant Extracts; Plant Stems; RAW 264.7 Cells; Republic of Korea
PubMed: 31547810
DOI: 10.1186/s12906-019-2659-5 -
The Journal of Clinical and Aesthetic... Jul 2021Tannins are considered an important phytochemical used in cosmetics and cosmeceuticals and are well-known for their astringent and antioxidant properties. is a plant...
BACKGROUND
Tannins are considered an important phytochemical used in cosmetics and cosmeceuticals and are well-known for their astringent and antioxidant properties. is a plant that grows in the Southern part of Thailand. Its fruits have an astringent taste, which might correlate with the presence of tannins.
OBJECTIVE
We sought to evaluate the efficacy of a hydrogel containing extract for controlling sebum.
METHODS
First, the extract of fruit was evaluated for its tannin content and astringent activity . Then it was formulated into a hydrogel in different concentrations. After, the safety and sebum-control efficacy of this hydrogel was tested in 10 healthy volunteers. The safety of this hydrogel was evaluated in volunteers using a closed patch test.
RESULTS
The results of the first part of the study indicated that extract contained 0.0359±0.0003mg of tannic acid equivalent per gram of extract, and its astringent activity was 87.45%±1.76%. When formulated into hydrogels of different concentrations, the results showed that the hydrogel containing 0.1% w/w had the highest stability profile. No irritation or allergy was observed. Separately, after usage twice per day for 28 consecutive days, the sebum content of the volunteers was decreased by -54.36%±13.71% relative to baseline.
CONCLUSION
The results from this study suggest that fruit extract might be an effective active ingredient for use by the cosmetic and cosmeceutical industry.
PubMed: 34840650
DOI: No ID Found -
Molecules (Basel, Switzerland) Jul 2021In the production of red wines, the pressing of marcs and extended maceration techniques can increase the extraction of phenolic compounds, often imparting high...
In the production of red wines, the pressing of marcs and extended maceration techniques can increase the extraction of phenolic compounds, often imparting high bitterness and astringency to finished wines. Among various oenological products, mannoproteins have been shown to improve the mouthfeel of red wines. In this work, extended maceration (E), marc-pressed (P), and free-run (F) Sangiovese wines were aged for six months in contact with three different commercial mannoprotein-rich yeast extracts (MP, MS, and MF) at a concentration of 20 g/hL. Phenolic compounds were measured in treated and control wines, and sensory characteristics related to the astringency, aroma, and colour of the wines were studied. A multivariate analysis revealed that mannoproteins had a different effect depending on the anthocyanin/tannin (A/T) ratio of the wine. When tannins are strongly present (extended maceration wines with A/T = 0.2), the MP conferred mouthcoating and soft and velvety sensations, as well as colour stability to the wine. At A/T = 0.3, as in marc-pressed wines, both MF and MP improved the mouthfeel and colour of Sangiovese. However, in free-run wine, where the A/T ratio is 0.5, the formation of polymeric pigments was allowed by all treatments and correlated with silk, velvet, and mouthcoat subqualities. A decrease in bitterness was also obtained. Commercial mannoproteins may represent a way to improve the mouthfeel and colour of very tannic wines.
Topics: Color; Humans; Membrane Glycoproteins; Odorants; Sensation; Tannins; Taste; Wine
PubMed: 34299408
DOI: 10.3390/molecules26144133 -
Journal of Evidence-based Complementary... Oct 2017Many of scientific evidences suggest that regular consumption of fruits and vegetables can prevent chronic diseases. In Northern Thailand, there are many vegetables that...
Health Promotion Potential of Vegetables Cultivated in Northern Thailand: A Preliminary Screening of Tannin and Flavonoid Contents, 5α-Reductase Inhibition, Astringent Activity, and Antioxidant Activities.
Many of scientific evidences suggest that regular consumption of fruits and vegetables can prevent chronic diseases. In Northern Thailand, there are many vegetables that are usually consumed by local people. In this study, 17 local vegetables were selected and extracted with 95% ethanol. The extracts were screened for 5α-reductase inhibitory activity, total tannin and flavonoid contents, astringent and antioxidant activities. The results showed that Spondias pinnata and Ocimum americanum had the highest tannin and flavonoid content, respectively. Neptunia oleracea was the most potent 5α-reductase inhibitor. For antioxidant activities, S pinnata was the most potent ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) radical scavenger and the most potent ferric reducer. Polygonatum odoratum was the most potent hydrogen peroxide scavenger and Leucaena leucocephala was the most potent DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenger among the tested samples. This suggests that local vegetables in Northern Thailand have a health promotion potential, which can be further developed as nutritional supplements, preventive medicines, and topical products for cosmetic purposes.
Topics: 5-alpha Reductase Inhibitors; Animals; Antioxidants; Astringents; Flavonoids; Health Promotion; Humans; Male; Plant Extracts; Rats; Rats, Sprague-Dawley; Tannins; Thailand; Vegetables
PubMed: 29228787
DOI: 10.1177/2156587216686689 -
Journal of Agricultural and Food... Dec 2006The objective of the present investigation was to examine the oral astringency and protein-binding activity of four structurally well-defined tannins, namely,...
The objective of the present investigation was to examine the oral astringency and protein-binding activity of four structurally well-defined tannins, namely, procyanidin [epicatechin16(4-->8)catechin], pentagalloyl glucose (1,2,3,4,6-penta-O-galloyl-beta-D-glucopyranose), castalagin, and grandinin, representing the three main structural categories of tannins, the proanthocyanidins, the gallotannins, and the ellagitannins. Astringency threshold and dos/response were determined by the half-tongue test using a trained human panel. Protein-binding stoichiometry and relative affinity were determined using radioiodinated bovine serum albumin in precipitation or competitive binding assays. Procyanidin and pentagalloyl glucose were perceived as highly astringent compounds and had relatively steep dose/response curves, but castalagin and grandinin had a lower mass threshold for detection. In vitro, procyanidin was the most effective protein-precipitating agent and grandinin the least. Increasing the temperature increased protein precipitation by the hydrolyzable tannins, especially grandinin. All four polyphenols had higher relative affinities for proline-rich proteins than for bovine serum albumin.
Topics: Adult; Biflavonoids; Biphenyl Compounds; Catechin; Catechols; Chemical Precipitation; Dose-Response Relationship, Drug; Female; Glycosides; Heterocyclic Compounds, 4 or More Rings; Humans; Hydrolyzable Tannins; Iodine Radioisotopes; Male; Proanthocyanidins; Protein Binding; Serum Albumin, Bovine; Taste
PubMed: 17147439
DOI: 10.1021/jf062272c -
Frontiers in Plant Science 2023The fruit of the persimmon (.) has high economic and nutritional value and is rich in flavonoids. Flavonoids are essential secondary metabolisms in plants. The...
The fruit of the persimmon (.) has high economic and nutritional value and is rich in flavonoids. Flavonoids are essential secondary metabolisms in plants. The association between persimmon astringency and changes in the proanthocyanidins (a flavonoid subclass) content is well-known. However, information on the relationships between different astringency types and other flavonoid subclasses and biosynthetic genes is more limited. In this study, an initial correlation analysis between total flavonoids and fruit astringency type, and KEGG analysis of metabolites showed that flavonoid-related pathways were linked to differences between mature pollination-constant non-astringent (PCNA) varieties ('Jiro' and 'Yohou') and pollination-constant astringent (PCA) fruit varieties ('Zhongshi5' and 'Huojing'). Based on these findings, variations in the expression of genes and metabolites associated with flavonoid biosynthesis were investigated between typical PCNA ('Jiro') and PCA ('Huojing') persimmons during fruit development. The flavonoid concentration in 'Huojing' fruit was significantly higher than that of 'Jiro' fruit, especially, in levels of proanthocyanin precursor epicatechin and anthocyanin cyanidin derivatives. Combined WGCNA and KEGG analyses showed that genes such as , , , , , , , , , , and in the phenylpropanoid and flavonoid biosynthesis pathways may be significant factors impacting the proanthocyanin precursor and anthocyanin contents. Moreover, interactions between the () and () transcription factors were found to be associated with the above structural genes. These findings provide essential information on flavonoid biosynthesis and its regulation in the persimmon and lay a foundation for further investigation into how astringency types affect flavor components in PCNA and PCA persimmons.
PubMed: 36923131
DOI: 10.3389/fpls.2023.1130047 -
Molecules (Basel, Switzerland) Jun 2020Astringency and bitterness are organoleptic properties widely linked to tannin compounds. Due to their significance to food chemistry, the food industry, and to human... (Review)
Review
Astringency and bitterness are organoleptic properties widely linked to tannin compounds. Due to their significance to food chemistry, the food industry, and to human nutrition and health, these tannins' taste properties have been a line of worldwide research. In recent years, significant advances have been made in understanding the molecular perception of astringency pointing to the contribution of different oral key players. Regarding bitterness, several polyphenols have been identified has new agonists of these receptors. This review summarizes the last data about the knowledge of these taste properties perceived by tannins. Ultimately, tannins' astringency and bitterness are hand-in-hand taste properties, and future studies should be adapted to understand how the proper perception of one taste could affect the perception of the other one.
Topics: Astringents; Food Analysis; Food Industry; Humans; Polyphenols; Tannins; Taste
PubMed: 32498458
DOI: 10.3390/molecules25112590 -
Foods (Basel, Switzerland) Oct 2022Because of the nutritional need of patients with celiac disease, producing quality gluten-free diet food is important. This study evaluated the use of persimmon flour on...
Because of the nutritional need of patients with celiac disease, producing quality gluten-free diet food is important. This study evaluated the use of persimmon flour on the properties of muffins. Persimmon flour obtained from the astringent variety 'Rojo Brillante', which is often discarded due to its characteristic astringency, was added to muffins replacing corn flour (10%, 20%, and 30%). Despite the height differences between the control muffin and the muffins with persimmon flour, similar mechanical parameters were obtained. As the percentage of persimmon flour increased, the muffin color was darker, turning toward a more reddish hue, mainly because of the intensification of nonenzymatic browning reactions. The sensory results showed high scores for taste attributes, the texture attributes were similar to the control, and astringency was hardly detected when persimmon flour was used. The content of tannins and carotenoids and their antioxidant activity increased significantly with an increasing amount of persimmon flour. After in vitro digestion, high recovery index values of soluble tannins and carotenoids were obtained in muffins with added persimmon flour. This study shows that the use of persimmon flour as a functional ingredient offers an opportunity to develop quality gluten-free muffins that reduce agricultural losses. Astringent varieties can be used, without applying a de-astringency treatment, as the astringency is removed during muffin baking due to tannins' insolubilization.
PubMed: 36359969
DOI: 10.3390/foods11213357