Tannins are a diverse class of naturally occurring polyphenolic biomolecules found in plants, particularly in bark, leaves, seeds, and fruit skins. They are characterized by their ability to bind and precipitate proteins, leading to astringency in foods and beverages like wine, tea, and unripe fruits. Tannic acid, a common hydrolysable tannin, consists of glucose esterified with gallic acid units. In food science, tannins contribute antioxidant properties, color stabilization, and antimicrobial effects but can inhibit nutrient absorption if consumed excessively. They are widely used in leather tanning, winemaking for clarification, and as food additives. Chemically, they exhibit variable structures ranging from condensed to hydrolysable forms, with molecular weights typically 500-3000 Da.