FREEZING DAMAGE TO BOVINE CREAM INDICATED BY RELEASE OF ENZYMES

Abstract
When washed cream was frozen slowly and thawed, some breaking of the emulsion occurred and on centrifugation a pellet, mostly membrane material, was obtained. Xanthine oxidase and alkaline phosphatase were present in this pellet, but little enzyme activity was found in the aqueous phase. The main effect of slow freezing was to force the fat globules together so that alteration and redistribution of the membranes could occur, and, on thawing, fat could coalesce. Rapid freezing on the other hand distributed fat globules more evenly so that less coalescence could occur on thawing.