Abstract
Corn grain was found to be readily fermented with a reasonable alcohol yield without any process of steaming or sterilizing the grain, if provided that the grain was finely pulverized and incubated as a slurry keeping the pH at 4.5 and the temperature between from 25 to 28°C after the addition of Rhizopus glucoamylase preparation and pressed baker's yeast. For the slurry consisted of one part of pulverized corn grain in two point seven weights of water, the addition of twenty units of glucoamylase and zero point seven mg of pressed baker's yeast per g starch of the slurry was enough for nearly completion of alcohol fermentation in four days under above conditions. Unlike the case of alcohol fermentation of polished rice grain powder by a similar method, no distinct effect of proteinase was observed for alcohol fermentation of corn grain powder. Also, no particular effect of pectin depolymerase in the glucoamylase preparation was observed for production of alcohol from corn grain. However, this enzyme was effective to reduce viscosity of the fermented beer. Buckwheat grain powder was also readily fermented by using the commercial enzyme. However, barley grain was not fermented so readily as corn or buckwheat grains.
