Some physicochemical properties of bovine colostral casein micelles
1988
Lee, C.W. (Cheju National Univ., Cheju (Korea R.). Dept. of Food Science and Nutrition) | Kim, Y.K. (Korea Univ., Seoul (Korea R.). Dept. of Animal Science)
This experiment was carried out to study the properties of casein of casein micelles obtained from colostral skim milk. As lactation progressed from parturition until 240h after calving, the content of total protein decreased while the proportion of casein to whey protein increased. Fractionation according to the size of casein micelle was done by ultracentrifugation at 100,000x g for 10 minutes(pellet 1), 30 minutes(pellet 2) and 60 minutes(pellet 3) and the serum casein was prepared by acid precipitation of final supernatant at pH 4.6. During the lactation period, the relative amount of pellet 1(large size) decreased, that of pellet 2(middle size) maintained nearly constant level except for pellet from parturition, that of pellet 3(small size) increased, and the serum casein showed almost constant level. The relative amounts of alpha s1 -casein and alpha s2 -casein and betta -casein-5P in the pellets decreased and that of K-casein increased markedly with decreasing micelle size, but the relative amounts of betta -casein-1P(f 29-209), (f 106-209) and (f 108-209) showed little change. The composition of the serum casein was different from that of the skim milk casein
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