PROTEIN STANDARDIZATION OF MILK AND DAIRY-PRODUCTS

Protein has become the most valuable constituent of bovine milk, owing to its high nutritional quality and unique physicochemical and functi onal properties, which are exploited to manufacture a diverse range of dairy products. The protein component of milk can be manipulated at t he production stage, by interfering with milk protein biosynthesis; or , more flexibly, by post-production technological means. Technological methods of protein adjustment include ultrafiltration to separate mil k into protein-rich and protein-free streams, which can then be recomb ined at different ratios, or the addition of various dried or liquid m ilk-based ingredients such as lactose, milk protein concentrates, whey protein concentrates, whey protein isolates or whey protein fractions . In contrast to the more general notion of protein adjustment, the te rm protein standardization, as currently envisioned by the Internation al Dairy Federation, refers to relatively minor adjustments of the tot al protein content that are consistent with the variation observed in normal milk production and limited to techniques that do not alter the natural ratio of whey protein to casein. Benefits of protein standard ization include: increased nutritional uniformity of fluid milk, conde nsed milk and milk powder; more accurate valorization of the protein c ontent of milk and other dairy products by the processors; better cont rol of product behaviour during thermal processes such as evaporation; improved consistency, texture, yield and nutritional quality of cultu red dairy products and cheese; and increased opportunities for new pro duct development.