Effect of Hydrogen Peroxide on Whey Protein Nitrogen Value of Heated Skimmilk

The effect on the whey protein nitrogen value of skimmilk treated with different concentrations of hydrogen peroxide in the skimmilk 10 rain before it was heated at 85 C for 30 rain was determined.Hydrogen peroxide decreased denaturation of skimnfilk.Disc eleetrophoresis patterns were tonipared for normal, heated, hydrogen peroxide-heated and hydrogen peroxideheated-eatalase-treated samples of a-laetalbumin, bovine serum albumin (BSA), fl-lactoglohulin, and acid whey.The alactalbumin band was lighter % the hydrogen peroxide-treated sample than in the normal or heated sample.Bovine sermn albmuin was denatured by heat treatment.Hydrogen peroxide prevented total denaturation of BSA.fi-laetoglobulin was denatured by heat treatment and extensively modified by hydrogen peroxide.The eleetrophoretie pattern of hydrog'en peroxide-heated acid whey had a darker baud in the position normally occupied by alactalbmuin.Hydrogen peroxide modified fl-laetoglobulin to form a band in the same position.A component not found hi hydrogen peroxide-heated acid whey was in the eIeetrophoretie pattern of acid wbey from hydrogen peroxide-heated skimmilk, possibly from a reaction of hydrogen peroxide with a casein protein to form a product not precipitated with the casein.Hydrogen peroxide has been used as a bactericidal agent to preserve and to treat milk used in manufacturing Swiss or Cheddar cheese (3, 8, 10).Previous experiments at this laboratory by Patel (9), with modified nonfat dD" milk for baking, indicated that treating skimmilk with hydrogen peroxide before forewarming at.89 C for 30 rain, then drying it, apparently decreased heat denaturation of whey proteins as determined by the tIarland-Ashworth method (4, 7).Received for publieation t~ebruary 2, 1967.Contribution no.651, Kansas Agricultural Experiment Station, Manhattan.This study was to determine whieh whey proteins, if any, were modified by hydrogen peroxide and were responsible for the decreased denaturation.