Indigenous enzymes in milk: Overview and historical aspects - Part 2

Between 1924 and about 1970, many indigenous enzymes were identified in milk. These were important as indicators of the adequate pasteurisation of milk (alkaline phosphatase, γ-glutamyl transferase) or of mastitis (N-acetylglucosaminidase, acid phosphatase) and some were considered to be important for the stability of milk (superoxidase dismutase, sulphydryl oxidase). Human and equine milk both contain a very high level of lysozyme, which is considered to have a significant protective effect on the neonate. Progress on the isolation and characterisation of these seven enzymes first isolated in the period 1925-1970, as well as ribonuclease, aldolase and glutathione peroxidase, from the milk of the cow and other species and their significance in milk and dairy products is reviewed in this article.