Influence of minor β-CN genotypes on coagulation properties and proteolytic pathways of bovine milk
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Published Version
Supplementary Data
Date
2025-07-14
Authors
Gai, Nan
Uniacke-Lowe, Therese
Goulding, David A.
O'Regan, Jonathan
Affolter, Michael
Kelly, Alan L.
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier Ltd
Published Version
Abstract
Numerous studies have examined the effects of the two most common β-casein (β-CN) genetic variants, A1 and A2, on the physicochemical and functional properties of bovine milk. However, relatively minor variants of this protein such as B and I remain under-researched. This study collected milk with four β-CN genotypes, A1B, A2B, A1I, and A2I, across three collection occasions to investigate their functional and proteolytic properties. Milk of the B variant exhibited similar behaviour to A1 regarding rennet and acid coagulation properties, while I was similar to A2. Furthermore, the Glu121-Arg122 and Arg122-Gln123 bonds in the β-CN B variant were more sensitive to plasmin-derived proteolysis than Ser122 in other variants, leading to more peptides from cleavage at Arg122-related sites. These findings support grouping genotypes based on the amino acid (AA) at position 67, as variants sharing the same AA at this position exhibit similar processability, while also highlighting the significant impact of AA at position 122 for proteolysis in milk or dairy products.
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Keywords
Aspartame , Mammals , Physicochemical properties , Proteolysis , Amino-acids , Bovine milk , Coagulation properties , Functional properties , Functionals , Genetic variants , Physicochemical property , Processability , Property , Coagulation
Citation
Gai, N., Uniacke-Lowe, T., Goulding, D. A., O’Regan, J., Affolter, M. and Kelly, A. L. (2025) 'Influence of minor β-CN genotypes on coagulation properties and proteolytic pathways of bovine milk', International Dairy Journal, 169, 106352 (8pp). https://doi.org/10.1016/j.idairyj.2025.106352