The influence of genetic variants of milk proteins on the compositional and technological properties of milk: 1. Casein micelle size and the content of non-glycosylated kappa-casein
Lodes, A.; Krause, I.; Buchberger, J.; Aumann, J.; Klostermeyer, H.
Milchwissenschaft 51(7): 368-373
1996
ISSN/ISBN: 0026-3788 Accession: 009589922
Milk samples (total = 203) containing different genetic variants of the milk proteins were analyzed for the average casein micelle diameter. In addition, most samples (n = 191) were analyzed for the content of non-glycosylated kappa-casein by IPG-IEF. Special attention was paid to the rare genetic variants (alpha-s1-Cn C, beta-Cn B or C, and kappa-Cn C or E). There were highly significant (p lt 0.001) relationships between the genotypes of the beta-Cn, kappa-Cn and beta-Lg locus and the average diameter of the casein micelles. The kappa-Cn locus had the greatest influence on the average micelle size, which increased from 190 nm to 229 nm in the following order: kappa-Cn BC/BB lt AB lt AC lt BE lt AA lt AE. A highly significant relationship (p lt 0.001) was also observed between the genotypes of the kappa-Cn locus and the content of non-glycosylated kappa-casein, which increased in the following order: AC/AE lt AA lt AB lt BE lt BC lt BB. Milk of the type beta-Lg BB contained significantly more (p lt 0.05) non-glycosylated kappa-casein than the type beta-Lg AB and AA. The allele kappa-Cn B in the genotypes AB, BC and BE induced a significantly greater amount of non-glycosylated kappa-casein than the alleles A, C and E, whereas the A-allele induces significantly less non-glycosylated kappa-casein than the alleles B and E.