Kaseïneeiwitten

Kaseïneeiwitten are a group of phosphoproteins found in milk, forming the main protein fraction of bovine milk and many other mammal milks. In dairy science they are typically classified into four major types: alpha_s1-casein, alpha_s2-casein, beta-casein and kappa-casein. Together with colloidal calcium phosphate, these proteins assemble into casein micelles, which give milk its unique functional properties and play a central role in cheese production.

The casein micelle is a submicellar aggregate stabilized by kappa-casein on the surface, which provides steric and electrostatic stability. Inside the micelle, casein molecules associate with calcium phosphate nanoclusters. This arrangement allows casein to be relatively insoluble at certain pH and calcium levels, enabling coagulation when processing conditions change, such as during rennet treatment or acidification.

In processing, coagulation of kaseïneeiwitten forms the curd, while whey proteins remain in the liquid phase. Rennet enzymes cleave kappa-casein, triggering micelle destabilization and gel formation, a principle exploited in cheese making. Acid-induced coagulation is another common method for producing curd, used in various dairy products.

Nutritionally, caseins are a high-quality protein source with essential amino acids and a slower digestion rate compared with whey proteins, leading to a more gradual release of amino acids. They are used widely in food products, including cheese, caseinates, and protein supplements. Some individuals have dairy protein allergies to kaseïneeiwitten, and dairy products may be avoided for other health or dietary reasons.