Heat Denaturation of the Specific Serum Proteins in Milk

Abstract

Milk was heat-treated at eight temperatures between 56° and 96° C. for 30 minutes, and the proteins in the serum obtained after removal of the denatured serum proteins with the casein at pH 4.6 were examined by a quantitative electrophoretic procedure. The denaturation curves obtained for each of the milk serum proteins indicated that the immune globulins are the least, and α-lactalbumin the most, heat resistant, with β-lactoglobulin and serum albumin showing an intermediate sensitivity. With the identification of three components in the electrophoretic patterns of the “proteose-peptone” fraction which were apparently present in the unheated milk, more of the electrophoretic entities of the milk serum proteins have now been elucidated. © 1955, American Dairy Science Association. All rights reserved.