NEET BIOLOGY

Detailed explanation-1: -Tannins are complex chemical substances derived from phenolic acids (sometimes called tannic acid). They are classified as phenolic compounds, which are found in many species of plants, from all climates and all parts of the globe.

Detailed explanation-2: -Principal human dietary sources of tannins are tea and coffee. Most wines aged in charred oak barrels possess tannins absorbed from the wood. Soils high in clay also contribute to tannins in wine grapes. This concentration gives wine its signature astringency.

Detailed explanation-3: -Tannins are, after lignins, the most abundant source of natural aromatic biomolecules and can be an alternative feedstock for the elaboration of chemicals, building blocks to develop polymers and materials. Tannins are present in all vascular and some non-vascular plants.

Detailed explanation-4: -There are two types of tannins, hydrolyzable tannins and condensed tannins. At the center of a hydrolyzable tannin, there is a carbohydrate such as d-glucose. The hydroxyl groups of the carbohydrate are partially or totally esterified with phenolic acids such as gallic acid (in gallotannins).