Abstract: Heat processing is necessary to effectively inactivate pathogenic bacteria in raw milk but simultaneously affect milk components. Whey protein denaturation and aggregation, lactose isomerization and degradation, and Maillard reaction occur successively in milk subjected to heat treatment at increasing temperatures. The reduced activity of active components (e.g. enzyme and whey protein) or the formation of reaction products (e.g. lactulose and furosine) indicates the heat load during thermal processing. Heat treatment conditions for milk as well as physiochemical changes and changes in the corresponding sensitive components during the process are discussed in this paper.

Key words: milk components, heat treatment, heat-sensitive components, heat-induced changes