Tannins (commonly referred to as tannic acid) are water-soluble polyphenols, molecular weight between 500 and 3 000, which, in addition to displaying the classic reactions of phenols, can precipitate alkaloids, gelatine, and other proteins.” Tannins are a diverse class of compounds and have various effects on health.
They are also used as antiseptics and astringents. Antioxidant activities confer upon the anti-carcinogenic and anti-mutagenic properties of tannins. Antimicrobial properties of tannins are shown against diverse group of bacteria, fungi and viruses.
Tannin with chemical formula C76H52O46 is a polyphenol compound that is colorless to yellowish, which can affect the tea itself taste, color and aroma. Tannins give tea astringency, color, and flavor. Tannins also cause darker colors in tea, which can be perceived as a sign of flavor strength. In fact, the development of tannins is unrelated to that of the aromatic compounds that create variety in tea flavor.
Tannins are mainly found in the cell vacuoles or in the cuticle (here cells don’t interfere with plant processes: only after death and cell breakdown do they become active in metabolic processes)
Tannins in tea
