Changes in Milk Proteins Treated with Hydrogen Peroxide

The effect of hydrogen peroxide on ~kimmilk and the individual proteins therefrom was studied, using eleetrophoretic mobility on polyacrylainide gel (P3_G) with and without m'e~ and 2-mercaptoetliano] (3IE).Also measured were whey protein and nonprotein nitrogen as a function of concentration and time of exposure to tt._,O~.A beatinduced K-casein and fi lactoglobnlin eoniplex was cxaniine-I ~m P.\(I with and without urea-)lE.?~ollowing hydrogen peroxide treatment of individual proteins, the migration rates on PAG eleetrophoresis were reduced for a~casein and fi-laetoglobulin, were increase:l for ¢7-casein and bovine serum albumin, and did not change for s-casein or a-lactalbundn.In skimmilk,/7-casein migration was slowed.When the samples and the gel both contained urea-)IE, a~-and fl-caseiu migration rates were redueed~ those of /?-laetoglobulin and BSA were increased, aiid those of s-casein and a-laetalbmnin were unchanged.Whey protein nitrogen decreased and nonlJroteb~ nitrogen increased as a function of tI~()., concentration and time.Hydrogen peroxide did not induce complex formation betweeu J-laetoglobulin and ~-easein.The beatinduced complex of these two proteins was ruptured by use of urea-)fE.