EFFECTS OF PROTEOLYTIC ACTIVITY ON THE CHARACTERISTICS OF AROMATIC RED RICE WINE

Abstract

The quality of rice wine made from uncooked, unpolished aromatic red rice grain was improved by use of a commercial preparation of acid protease from Aspergillus niger during ethanol fermentation. The fermentation rate of the mash which contained the acid protease was much higher than that of mash that did not contain the preparation of acid protease. The rice wine made from uncooked, polished aromatic red rice, which usually had a less acceptable aroma, was improved by use of the preparation of acid protease, and large amounts of isobutyl alcohol, n-propyl alcohol and ethyl acetate were detected in the resultant rice wine. By contrast, the quality of rice wine made from the bran fraction of aromatic red rice was not improved by the preparation of acid protease. The polished rice fraction of aromatic red rice was affected by the acid protease and the aromatic quality of the rice wine was improved. The aromatic characteristics of red rice wine made from cooked, unpolished aromatic red rice grains, which was rather inferior in terms of both aroma and color, were also improved by the addition of the preparation of acid protease during ethanol fermentation. Thus acid protease has beneficial effects on the production of aromatic red rice wine.