NITROGENOUS CONSTITUENTS OF BREWING MATERIALS XII. FOAM-STABILIZING SUBSTANCES IN BEER

Abstract

Material of comparatively high molecular weight was recovered from whole beer by means of a previously employed modification of the Cohn method. This fraction, which contained the bulk of the foam-stabilizing capacity of the original beer, was sub-fractionated by means of gel filtration. Five distinct components were thus obtained of which one, amounting to approximately 10% of the original material, had the greatest foam-stabilizing activity. Whereas this active fraction contained, in addition to protein, some 50% carbohydrate, including all the pentose material of the original, the inactive fractions contained little or no carbohydrate. However, further fractionation led to the removal of 60% of this carbohydrate but without removal of foam-stabilizing activity. All those fractions which could produce foams either contained protein or were substantially of protein nature.