Astringents: Agents, usually topical, that cause the contraction of tissues for the control of bleeding or secretions.Nontherapeutic Human Experimentation: Human experimentation that is not intended to benefit the subjects on whom it is performed. Phase I drug studies (CLINICAL TRIALS, PHASE I AS TOPIC) and research involving healthy volunteers are examples of nontherapeutic human experimentation.Hydrolyzable Tannins: Polymeric derivatives of GALLIC ACID that are esters of a sugar.Taste Perception: The process by which the nature and meaning of gustatory stimuli are recognized and interpreted by the brain. The four basic classes of taste perception are salty, sweet, bitter, and sour.Grape Seed Extract: Exudate from seeds of the grape plant Vitis vinifera, composed of oils and secondary plant metabolites (BIOFLAVONOIDS and polyphenols) credited with important medicinal properties.Alum Compounds: Aluminum metal sulfate compounds used medically as astringents and for many industrial purposes. They are used in veterinary medicine for the treatment of ulcerative stomatitis, leukorrhea, conjunctivitis, pharyngitis, metritis, and minor wounds.Tannins: Polyphenolic compounds with molecular weights of around 500-3000 daltons and containing enough hydroxyl groups (1-2 per 100 MW) for effective cross linking of other compounds (ASTRINGENTS). The two main types are HYDROLYZABLE TANNINS and CONDENSED TANNINS. Historically, the term has applied to many compounds and plant extracts able to render skin COLLAGEN impervious to degradation. The word tannin derives from the Celtic word for OAK TREE which was used for leather processing.Diospyros: A plant genus of the family EBENACEAE, order Ebenales, subclass Dilleniidae, class Magnoliopsida best known for the edible fruit and the antibacterial activity and compounds of the wood.Aluminum Compounds: Inorganic compounds that contain aluminum as an integral part of the molecule.Drinking Water: Water that is intended to be ingested.Taste: The ability to detect chemicals through gustatory receptors in the mouth, including those on the TONGUE; the PALATE; the PHARYNX; and the EPIGLOTTIS.Meat Products: Articles of food which are derived by a process of manufacture from any portion of carcasses of any animal used for food (e.g., head cheese, sausage, scrapple).Catechin: An antioxidant flavonoid, occurring especially in woody plants as both (+)-catechin and (-)-epicatechin (cis) forms.