Enzymes of significance to milk and dairy products

When considering the processing and quality of milk and dairy products, a number of enzymes are of significance. These fall broadly into 3 categories: 1. Indigenous enzymes: Fresh raw bovine milk contains a heterogeneous group of enzymes, derived from various sources. While different authors may use different nomenclature to indicate the origin of enzymes, in this chapter, enzymes of bovine origin that are found in milk will be referred to as indigenous. While the complement of milk enzymes has not been completely classified, and gaps in knowledge and understanding clearly occur, the principal classes of enzymes include proteolytic and lipolytic enzymes, phosphatases, antimicrobial enzymes, e.g., lysozyme and lactoperoxidase, and a number of other enzymes, such as xanthine oxidase. Approximately 60 indigenous enzyme activities have been reported in bovine milk, of which ca. 20 have been characterized (1, 2). The milk of mammals other than the cow probably contains similar enzyme profiles, although most have not been studied in detail (2).