Stability of Sterile Model Systems of Milk Proteins

Sterilized solutions of casein, of casein and fl-lact0globulin, of a-casein, and of K-casein were stored at 35, 50, 65, and 80 C to determine the effect of temperature on the stability of the protein to Ca ++. Results are related to gelation of sterile concentrated nfilk.Sterile casein solution containing 0.13 M Ca gelled and lost 40 to 70% of its stability to Ca ++.Sterile solutions of casein and fl-lactoglobulin containing the same amount of calcium gelled more rapidly with loss of stability of from 20 to 30%.fl-Lactoglobulin promoted gelation of casein, a-Casein solutions containing 0.075 ~ Ca gelled with loss of stability of from 40 to 70%.K-Casein also lost its ability to stabilize a~-casein following sterilization and storage.Nonprotein N increased in solutions of casein, of casein and fl-lactoglobulin, of a-casein, and of K-casein during storage, and increased more at the higher storage temperatures.