Protein (tanpakushitsu)

Protein is an important component of the bodies of animals and plants, and a high-molecular-weight compound essential to life. Rice, the main ingredient of sake, also contains protein, chiefly a type called glutelin (oryzenin). Rice protein also acts as enzymes during fermentation, contributing to alcohol production and the development of flavor. Under the influence of heat, chemical agents, radiation and the like, proteins can lose their physiological function or change their properties. This phenomenon is called "protein denaturation." For example, when heat treatment is applied during sake brewing, certain proteins can be denatured, which may affect the taste and aroma of the sake.