Astringency flavonoid

Flavonoids (sensu largo, i.e., including flavanoids) are important components of grapes and essential to wine quality. They are responsible for the color and astringency of red wines as well as for the yellow hue of oxidized white wines, and are also involved in the development of... 

Assessment of taste is achieved by sensory analysis, from very simple experiments such as triangular tests aiming at determining detection thresholds to complex descriptive analysis approaches. A method referred to as time-intensity that consists in recording continuously the intensity of a given sensation over time under standardized conditions has been applied to study flavonoid bitterness and astringency properties. 

Noble, A.C., Astringency and bitterness of flavonoid phenols. In Chemistry of Taste Mechanisms, Behaviors, and Mimics (eds P. Given and D. Paredes), American Chemical Society, Washington, DC, 2002, p. 192. 

Hatano T, Kagawa H, Yasuhara T, Okuda T. Two new flavonoids and other constituents in licorice root their relative astringency and radical scavenging effects. Chemical Pharmaceulical Bulletin. 1988 36(6) 2090-2097. 

Ampelopsis japonica (Thunb.) Mak. A. bodinieri (Levi. Vant.) Rehd. A. contonensis (Hook Arn.) Planch. A. humulifolia Bunge. Bai Lian (Peppervine) (root bark, stem, leaf) Flavonoids, glucosides, amino acids.48-60 Anodyne, astringent anticonvulsive, detoxicant, treat tubercular cervical nodes, hemorrhoidal bleeding. Treat pain of rheumatism. 

Bauhinia championi Bentham . variegata L. Jiu Hua Teng (Orchid tree) (bark, sepal) Kaempferol-3-galactoside, daempferol-3 -rutinoside, protein, flavonoids, carbohydrates, stigmasterol, beta-sitosterol, beta-p glucophyranoside.50-450 Astringent, tonic, treat scrofula, skin ailments, leprosy, ulcers, and diarrhea. 

Salvia plebeia R. Brown Li Zhi Cao (aerial part) Flavonoids, homoplantaginin, hispidulin, eupafolin, essential oils.48 Diuretic, vermifuge, astringent. 

N.A. Flavonoids, santhophylls, volatile oil, acetylenes, sterols, and tannins.99 As an astringent, diuretic, to treat bladder and kidney problems. Staunch blood flow, for uterine hemorrhage. 

N.A. Hydroquinones (arbutin), flavonoids, triterpene, methyl salicylate, tannins." An astringent, tonic, and diuretic. An infusion for urinary tract problems. 

N.A. Silicic acid, silicates, flavonoids, phenolic acid, nicotine, sterols.100 Regeneration of connective tissue, clotting agent, astringent effect on genitourinary system. 

N.A. Limonene, terpineol, linalool, tannins, flavonoids, terpenes." As astringent, for gastrointestinal problems, bleeding hemorrhoids. 

N.A. Hypericin, hyperoside, rutin, quercitin, chlorogenic acid, pseudohypericin, flavonoids.99 100 102 Antidepressant, anti-inflammatory, diuretic, antiseptic and astringent properties. 

N.A. Coumarins, naphthaquinones, lawsone, flavonoids, sterols, tannins.99 As a gargle for sore throats, treat diarrhea, dysentery. An astringent, prevent hemorrhaging. 

N.A. Saponins, flavonoids, vitamin A." Prevent excessive bruising and stimulate tissue repair. An astringent, treats tuberculosis. 

N.A. Tannins, flavonoids, polyphenols, silicic acid, mucilage.99102 With astringent and diuretic properties. Treat diarrhea, hemorrhoids, expel worms. 

N.A. Fraxinus americana L. /. excelsior L. F. omus L. Coumarins, flavonoids, tinnins, volatile oil.99 A tonic, astringent, laxative, diuretic, treat fevers. 

Proanthocyanidins are polymeric flavonoid compounds composed of flavan-3-ol subunits (unitii.3), and are responsible for bitterness and astringency in some foods and beverages. This unit describes methods for extracting and purifying proanthocyanidins, and for determining their subunit composition by HPLC. Based upon HPLC results, the average degree of polymerization and the conversion yield for purified proanthocyanidins can be determined. 

Proanthocyanidins are polymeric flavonoid compounds composed of flavan-3-ol subunits (Fig. II. 4.1), and are widely distributed in the plant kingdom, including plants that are important as a source of food (Santos-Buelga and Scalbert, 2000). They impart bitter and astringent properties. In addition, these compounds may have potential health effects (Santos-Buelga and Scalbert, 2000). 

Flavan-3-ols represent the most common flavonoid consumed in the American and, most probably, the Western diet and are regarded as functional ingredients in various beverages, whole and processed foods, herbal remedies, and supplements. Their presence in food affects quality parameters such as astringency, bitterness, sourness, sweetness, salivary viscosity, aroma, and color formation [Aron and Kennedy, 2007]. Flavan-3-ols are structurally the most complex subclass of flavonoids ranging from the simple monomers ( + )-catechin and its isomer (—)-epicatechin to the oligomeric and polymeric proanthocyanidins (Fig. 1.10), which are also known as condensed tannins [Crozier et al., 2006b]. 

Phenylpropanoids have an aromatic ring with a three-carbon substituent. Caffeic acid (308) and eugenol (309) are known examples of this class of compounds. Phenylpropanoids are formed via the shikimic acid biosynthetic pathway via phenylalanine or tyrosine with cinnamic acid as an important intermediate. Phenylpropanoids are a diverse group of secondary plant compounds and include the flavonoids (plant-derived dyes), lignin, coumarins, and many small phenolic molecules. They are known to act as feeding deterrents, contributing bitter or astringent properties to plants such as lemons and tea. 

Grape phenolics compounds are important to wine colour, flavour, astringency and bitterness, with red wines generally containing 1200-1800 mg gallic acid equiv-alents/L of total phenolics, six- to ninefold more than present in white wines (Kennedy et al. 2006). Hydroxycinnamic acids (non-flavonoid phenolics) are major phenolic compounds of white wines and are responsible for their colour. Other non-flavonoid phenolics contribute flavour, such as vanillin, vinyl phenols and gallic acid. Vinyl and ethyl phenols, which can be present to variable extents, elicit phenolics, medical, Bandaid , barnyard and spicy characters in wine, which are generally... 

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