The role of alpha-glucosidase of brewing yeast in high gravity brewing.

Fukui, N., Nakatani, K., Kanagawa, K. and Nagami, K.

Abstract
Alpha glucosidase, a yeast enzyme, plays a major part in the fermentation process. The authors studied the influence of sugar assimilation and fermentation conditions on yeast growth and intracellular alpha glucosidase activity during fermentation. Details of equipment and methods used are given. It was found that the specific activity of alpha glucosidase during the stationary stage was related to the yeast's maltose assimilation rate, which accelerated when the activity increased. The alpha glucosidase activity decreased as the amount of glucose assimilated by the yeast rose. The overall fermentation rate was accelerated by increasing the pitching rate and also by increasing the dissolved oxygen content of the wort; both were found to work by increasing the maximum viable yeast population, but the former also prolonged the period of alcohol production at a high rate, which is thought to be related to alpha glucosidase activity. Results are given in the form of graphs.
Keywords : analysis brewers' yeast enzyme fermentation glucose high gravity brewing maltose maltotriose oxygenation pitching rate wort