关键词: 酸, 苦, 咸, 甜, 鲜, 结构化学

Abstract:

Gustation is an animal sense of feeling the urge of internal metabolism in response to its environmental food messages. It is one of the instincts formed through the selective process in nature for survival struggles. Umami, saltiness and sweetness are signal of food attractart while bitterness, astringency and pungency are those of food repellent. Sourness can be either one contingent upon the time and place of the subject and/or the object. Feature structures of basic tastants are as follows: First of all they must be polarized 2such that they can be attracted by the corresponding receptors of opposite polarity. As these interactions are a chemical phenomenon, Lewis'generalized idea of acid A and base B may be employed to epitomize the structure high lights of different tastant molecules. Sour molecules are acidic ionizable compounds represented as HA and bitter molecules are basic ones often of a covalent nature readily polarizable, assigned here as B. Salty molecules are neutral salts A⁺ B^- of high ionic character and the sweet tastants arc amphoterie compounds with covalent character A-B or AH-B. These formulae stand for the essential sapophoric groups with whicha hydrophobic part C may be attached and may serves as an auxosapophorie moiety. Umami molecules may te regarded as a structural combination of the latter two essences A⁺B^--(C_1-9)AH-B to form an entirely new tastant. The structrual chemistry of salty and umami molecules are then especially introduced in this paper.

Key words: Sourness, Bitterness, Saltinnss, Sweetness, Umami, Structure-chemistry