Proteins are polypeptide chains of amino acid residues. Amino acids are the building blocks of protein.


Amino acids, when absorbed from the proteins contained in food, are involved in the building of tissues and in the synthesis of sugars and lipids.

Milk proteins play an important role in neonate nutrition and health: the amino acid types and concentrations in cow's milk protein are similar to the amino acid requirements of humans.

Caseins, beta-lactoglobulin, alpha-lactalbumin, serum albumin and immuoglobulins are the major proteins in cow's milk.

The primary group of milk proteins are the caseins (3/4 of totally proteins). Caseins have an amino acid composition which is important for growth and development of the nursing young and they are fairly easily digestible in the intestine.

Other proteins present in milk preparation are whey proteins. There are many whey proteins in milk and the specific set of whey proteins found in mammary secretions varies with the species.

The major whey proteins in cow's milk are beta-lactoglobulin and alpha-lactalbumin. Beta-lactoglobulin's function is not known; alpha-lactalbumin is an important protein in the synthesis of lactose and its presence is central to the process of milk synthesis.Other whey proteins are the immunoglobulins and serum albumin, enzymes, hormones, growth factors, nutrient transporters, disease resistance factors and others.

The combined intake of caseins and whey proteins results in an optimal balance of amino acids.

Most whey proteins are relatively less digestible in the intestine, although all of them are digested to some degree. When whey protein is not digested fully in the intestine, some of the intact protein may stimulate a localized intestinal or a systemic immune response. This is sometimes referred to as milk protein allergy and is most often thought to be caused by beta-lactoglobulin.