Maltose fermentation and leavening ability of baker's yeast

Abstract

Baker's yeasts with completely differenta-glucoside permease,a-glucosidase and maltose fermentation activities may still be almost equivalent in their leavening ability. A repression of the maltose uptake system of yeast occurs in a medium that besides maltose contains glucose or fructose. Hardly any maltose is utilized until the concentration of monosaccharide falls below 0.2% and a derepression of the maltose uptake system starts. It is almost conceivable that the repression also takes place in dough, as the hexose content of wheat flour is high enough to repress the maltose uptake system. The activities of the maltose fermenting system do not influence the leavening ability of the yeast as measured for the first hour of proofing, although maltose is the predominant sugar present.