2.2.2. Milk Proteins

The content of milk protein is an important component of milk, both a source of good nutrition (contains 18 amino acids, including 9 essential amino acids) and a factor in determining the price of milk [23]. The protein in milk ranges from 2.9 to 4%. The proteins in milk can be fractionated into two defined groups: casein and serum protein. The ratio of casein to whey proteins consists is 80:20. Casein is in the form of relatively large colloidal particles-micelles and contains four fractions (αS1, αS2, β, and κ-caseins) and their fragments. Whey proteins are heterogeneous and include globular proteins that differ in structure and properties-β-lactoglobulin, α-lactoglobulin, immunoglobulins, lactoferrin, and serum albumin. The third group can be distinguished, these include proteins of the shells of fat globules, which make up only about 1% of all milk proteins. The milk proteins contain the nine essential amino acids required by humans, making it an important human food [24,25].
