Taste astringency

Features Stem nearly simple, reddish, furrowed, up to two feet high. Leaves radical, palmate, long-stalked, glossy green above, paler underneath, serrate, nearly three inches across. White, sessile flowers, blooming in June and July. Taste astringent, becoming acrid. 

Characters.—Spheroidal, about three quarters of an inch in diameter hard colour reddish-brown taste astringent. 

Polyphenols Sinapicacid Free and esterified phenolic compounds condensed tannins Dark colour Bitter taste Astringent effects React with fimctional groups at protein, similar to isothiocyanates Use of reducing agents to avoid oxidation Pre-extraction with alcohols Membrane processing Adsorption processing... 

The metallic taste (12,19,20) is not ascribed to any special taste buds or mouth area. Along with pungency (the hot taste of peppers), astringency (the puckering taste of alum), and cold taste (the cool effect of menthol), the metallic taste is called a common chemical sense (21). 

The taste of saccharin was further studied, and it was found that (1) the alkaline-earth-metal salts are sweet, whereas the heavy-metal salts are astringent (2) the sweet taste is lost if the sulfimide ring is cleaved, or if... 

The catechins are soluble in water, colorless, and possess an astringent taste. They are easily oxidized and form complexes with many other substances including the methylxanthines.44 Epigallocatechin gallate is the... 

Black tea taste is primarily a function of the polyphenols, caffeine, and aroma components. Astringency, an important characteristic of the organoleptic sensation, has been described as consisting of a tangy and a nontangy component.95... 

The organoleptic properties of black tea depend to a considerable extent on the astringency resulting from the interaction of caffeine with the oxidized galloyl ester of the flavanols. The aroma components of black tea also constitute a unique flavor profile that blends well with the taste of the nonvolatile materials. The caffeine provides a moderate level of stimulation, which adds further to the appeal of the beverage, although tea has been shown to provide relaxation as well as revival of character.119... 

We all drank the ayahuasca. The taste was sharp and astringent, like a sauce of leather and mole, but it faded quickly as the liquid went churning through our guts. Dennis took only one more mushroom to help him hear the tone. The darkness outside was utter and we had no clock it seemed hours since Dave and Vanessa had left us. All was finally in readiness the living mushroom, the harmine brew, and a harmine smoking mixture, "just in case." After we each had about a half-cup of the ayahuasca infusion, we settled down to wait. 

The dihydrate Zn(C2H302) 2H2O is a white lustrous powder faint acetic acid odor astringent taste monoclinic crystals density 1.735 g/cm loses water at 100°C decomposes at 237°C readily dissolves in water, 43g/100 mL at 20°C soluble in alcohol. 

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. 

The astringency of wine tannin fractions appears to be correlated to the content of flavanol units released after thiolysis regardless of their environment in the original mol-ecules. Anthocyanins contributed neither bitterness nor astringency. Whether incorporation of anthocyanin moieties in tannin-derived structures affects their interactions with proteins and taste properties remains to be investigated. 

Valentova, H. et al., Time-intensity studies of astringent taste. Food Chem. 78, 29, 2002. 

Noble, A., Why do wines taste bitter and feel astringent In Wine Flavor (eds A.L. Waterhouse and S. Eberler), American Chemical Society, Washington, DC, 1998, p. 156. 

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. 

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