Effect of protein concentration on rates of thermal denaturation of whey proteins in milk.

摘要

The effects of varying the concentrations of total protein (25-200% of the initial concentration in skim milk), whey protein (123, 146, 178 and 259%) and casein (150 and 200%) on levels of thermal denaturation of 4 main whey protein fractions in skim milk, namely immunoglobulins, serum albumin/lactoferrin, beta-lactoglobulin and alpha-lactalbumin, were examined by gel permeation fast protein liquid chromatography. On heating at 80deg C, the rates of denaturation of the individual whey proteins in skimmilk increased with total protein concentration and, to a lesser extent, with increasing whey protein concentration. The levels of denaturation of the whey proteins were not affected by increasing micellar casein concentration but decreased markedly when the casein concentration was reduced below that in skim milk. In milks from different cows, rates of denaturation of individual whey proteins were not affected by beta-lactoglobulin phenotype but were higher in milk from cows in late-lactation.