PRODUCTION OF RICE VINEGAR FROM UNCOOKED RICE BRAN BY A PARALLEL-COMBINED PROCESS CONSISTING OF SACCHARIFICATION, ETHANOL FERMENTATION AND ACETIC-ACID FERMENTATION - STUDIES ON ACETIC-ACID FERMENTATION .4.

An improved method was developed for production of rice vinegar from uncooked rice-bran by a parallel-combined process consisting of enzymatic saccharification, ethanol fermentation with acetic acid tolerant yeast and acetic acid fermentation with acetic acid bacteria. An acid stable glucoamylase from Rhizopus sp. which is able to produce glucose enzymatically from raw starch in the presence of acetic acid was chosen for the purpose. In addition to a common acetic acid bacteria, Saccharomycodes ludwigii which demonstrates a normal ability of ethanol fermentation in 1% acetic acid was selected as an acetic acid tolerant yeast. In the actual process of rice vinegar fermentation, these three independent steps were allowed to act at a time in one mash batch containing 12-14% (w/v) of uncooked rice-bran, and incubation was carried out as static culture through the processs. As a result, the newly developed method was evaluated to be superior to classic conventional methods on the acetic acid yield.