In cattle, at least 39 variants of four casein proteins (αS1-, β-, αS2- and κ-casein) have been described to date, some of which are breed specific. It is known that a large number of these variants have an influence on milk-production traits and cheese making properties. In addition, milk protein variants are used for breed characterization and biodiversity investigations. Furthermore, they are involved in various aspects of human nutrition. First is the occurrence of alleles associated with a reduced content of different caseins which might be exploited for the production of milk with particular nutritional qualities; that is, hypoallergenic milk. On the other hand, the frequency of these alleles can be decreased by selection using simple DNA tests, thereby increasing the casein content in milk used for cheese making. Last but not least, the biological activity of peptides released from milk protein digestion can be affected by amino acid exchanges or deletions resulting from gene mutations. In my B. Sc. Thesis, I concentrated on the bovine milk proteins, aiming both to emphasize the pioneer work and exhaustive reviews that have already been carried out on the subject and to elucidate some of the main aspects affecting animal breeding and human nutrition.
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