The effect of UHT processing and storage on milk proteins

UHT milk is produced by a high-temperature process and is stored at room temperature, which can be up to 50°C, for several months. Both of these factors cause considerable changes to the milk proteins. Many of the changes have little or no effect on the organoleptic and nutritional attributes of the product. Such changes include whey protein denaturation, lactosylation, deamidation, and polymerization. However, other changes such as proteolysis can cause flavor and textural defects. Defects include bitterness, gelation, sedimentation, and fat separation. This chapter explores the several changes that occur in the proteins in UHT milk during both processing and storage and discusses ways in which the adverse changes can be minimized or prevented.