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1996 Fiscal Year Final Research Report Summary

Analysis of calcium phosphate cross-linkage in casein micelles by radioactive isotope Professor

Research Project

Project/Area Number 07660362
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Zootechnical science/Grassland science
Research InstitutionKagoshima University

Principal Investigator

AOKI Takayoshi  Faculty of Agriculture, Department of Biochemical Science & Technology Kagoshima University, 農学部, 教授 (70034460)

Project Period (FY) 1995 – 1996
Keywordscasein micelle / artificial casein micelle / micellar calcium phosphate / colloidal calcium phosphate / radioactive isotope
Research Abstract

Although calcium and inorganic phosphate (Pi) in bovine casein micelles were at equilibrium with those in soluble form, their properties have not yet been elucidated sufficiently. In this study, the behavior of calcium and Pi in casein micelles was studied using ^<45>Ca and ^<32>P by ultrafiltration, equilibrium dialysis and gel permeation HPLC in the presence of 6M urea. Approximately 30-40% of the calcium and Pi in bovine casein micelles were estimated to be hard to exchanged with those in soluble phase. Then, artificial casein micelles were prepared at a casein concentration of 2.5% with 30-40 mM calcium, 22-27 mM Pi and 10mM citrate using ^<45>Ca and ^<32>P.About 75 and 65% of micellar calcium and Pi in artificial casein micelles were exchanged after dialysis of artificial casein micelles against a simulated milk ultrafiltrate at 4゚C for 72h.The percentage of ^<45>Ca and ^<32>P in the fraction of casein aggregates cross-linked by micellar calcium phosphate were 26.9 and 27.6%, which decreased to about 10% after equilibrium dialysis against a simulated milk ultrafiltrate at 4゚C for 72h. The proportion of exchanged calcium and Pi in artificial casein micelles during dialysis for 72h were higher at 25゚C than at 4゚C,suggesting that the exchange of calcium and Pi between diffusible and micellar phases depended on temperature. The effects of calcium and Pi on the formation and properties of casein micelles were also examined using response surface analyzes. The results suggest that the exchange of calcium and phosphate between diffusible and micellar phases proceeds slowly, and a proportion of calcium and Pi in casein micelles is difficult to exchage.

  • Research Products

    (6 results)

All Other

All Publications (6 results)

  • [Publications] Z.P.Zhang and T.Aoki: "Behaviour of calcium and phosphate in Bovine casein micelles." International Dairy Journal,. 6. 769-780 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Z.P.Zhang,M.Fjii and T.Aoki: "Behavior of calcium and phosphate in Bovine casein micelles." Journal Dairy Science,. 79. 1722-1727 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.Aoki,T.Uehara,A.Yonemasu and M.Zin El-Din: "Response surface analysis of the effects of calcium and phosphate on the formation and properties of casein micelles." Journal of Agricultural and Food Chemistry.44. 1230-1234 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Zhu Ping Zhang and Takayoshi Aoki: "Behavior of calcium and phosphate in Bovine casein micelles." International Dairy Journal. 6. 769-780 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Zhu Ping Zhang, Makoto Fjii and Takayoshi Aoki: "Behavior of calcium and phosphate in Bovine casein micelles." Journal Dairy Science. 79. 1722-1727 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Takayoshi Aoki, Toshihiko Uehara, Akihisa Yonemasu, Mohamed Zin El-Din: "Response surface analysis of the effects of calcium and phosphate on the formation and properties of casein micelles." Journal of Agricultural and Food Chemistry. 44. 1230-1234 (1996)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-03-09  

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