Some Physicochemical Properties of Bovine Colostral Casein Micelles

젖소 초유 Casein Micelle의 이화학적 성질에 관한 연구

  • Lee, Chul-Won (Department of Food Science and Nutrition, Cheju National University) ;
  • Kim, Young-Kyo (Department of Animal Science, Korea University)
  • 이철원 (제주대학교 식품영양학과) ;
  • 김영교 (고려대학교 축산학과)
  • Published : 1988.04.01

Abstract

This experiment was carried out to study the properties of casein micelles obtained from colostral skim milk. As lactation was progressed from parturition until 240h after calving, the content of total protein decreased while the proportion of casein to whey protein increased. Fractionaltion according to the site of casein micelle was done by ultracentrifugation at 100,000 x g for 10 minutes(pellet 1), 30 minutes(pellet 2) and 60 mintes(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 pllet from parturition, that of pellet 3(small size) increased, and the serum casein showed almost constant level. The relative amounts of ${\alpha}_{s1}-casein\;and\;{\alpha}_{s2}-casein\;and\;{\beta}-casein-5P$ in the pellets decreased and that of x-casein increased markedly with decreasing micelle size, but the relative amounts of ${\beta}-casein-1P$(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.

Keywords

colostral milk;casein micelle;physicochemical properties of milk