The Mechanism of Formation of High Concentration Alcohol in Sake Brewing Part I. An EffectiveComponent of Rice and its Function

Abstract

The sake brewing is distinguished from other wine brewings by its formation of high concentration alcohol, usually forming about 20 vol.% of alcohol in final concentration. I. Yamasaki indicated that the presence of the solid part of koji in the medium was essential for the formation of high concentration alcohol. In the present paper the effective component of rice was investigated. The experimental method was simplified by a gradual addition of sucrose instead of the saccharification of rice starch by koji. Inoculum size of Saccharomyces sake was 3×107/ml. The addition of a protein of rice, oryzenin as well as koji and rice, resulted in the formation of such high concentration alcohol as 18~20%. The UV-absorption of tryptophol at 280 mμ which had proved to be most toxic to the yeast among higher alcohols, decreased by adding oryzenin. Consequently oryzenin was shown to have an ability to adsorb tryptophol. © 1967, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.