Effect of heat and homogenization on riboflavin photolysis in milk

Abstract

The influence of milk heat treatment and homogenization on photolytic degradation of riboflavin in milk was examined. Milk samples heated at 80, 100 and 120 °C were used for light exposure experiments and determinations of whey protein denaturation, casein micelle size and browning. Heat treatment of skim milk increased riboflavin photostability. The large decrease in rate constants in heated as compared to unheated milks could be due mainly to denaturation of whey proteins. Further decrease in rate constants with prolonged heat treatments could be due to an increase in casein micelle size and browning. Homogenization of whole milk slightly increased riboflavin photostability, but differences in pressure had no significant effect on photodegradation.