Milk proteins: An overview

Proteins represent one of milk's macroconstituents (along with water, lipids, and carbohydrates), accounting for ~. 3.0%-3.5% of the total composition. In bovine milk, there are two main protein families, namely, casein and whey protein. Caseins are milk-specific proteins that exist as colloidal aggregates dispersed in milk serum. The bovine milk protein system is casein dominant, which enables large quantities of calcium to be delivered to the neonate. The natural function of milk is to supply the neonate of the species with its complete nutritional requirements for a period of time postpartum. Milk proteins (and their peptides) provide essential amino acids and amino groups for the biosynthesis of nonessential amino acids and, when in excess, also supply energy. They also provide many of milk's physiological functions, performed by immunoglobulins, enzymes, enzyme inhibitors, growth factors, hormones, and antibacterial agents. The development of advanced fractionation and processing techniques has led to the production of many milk-derived ingredients that have different functional properties and applications.