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pH-Induced dissociation of bovine casein micelles. I. Analysis of liberated caseins

Published online by Cambridge University Press:  01 June 2009

Douglas G. Dalgleish  and
Andrew J. R. Law
Douglas G. Dalgleish
Affiliation:
Hannah Research Institute, Ayr KA6 5HL, UK
Andrew J. R. Law
Affiliation:
Hannah Research Institute, Ayr KA6 5HL, UK
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Summary

The dissociation of caseins of different types from casein micelles in milk, acidified to different pH values in the range 4·9–6·7, and at temperatures of 4, 20 and 30 °C, has been studied. In contrast to a number of previous findings, it was shown that caseins of all types were dissociated from the micelles, although in all cases β-casein was in highest concentration. The amounts and proportions of all of the caseins were found to be pH- and temperature-dependent, especially the former. Studies of the proportions of the different caseins liberated suggested that, at a defined temperature, the proportions of κ;- and αs2-caseins were independent of pH, while the proportions of β- and αsl-caseins were variable, changes in one being compensated by changes in the other. The manner in which the proportions of the αsl-casein and β-caseins changes with pH was found to be temperature-dependent.

Type
Original articles
Information
Journal of Dairy Research , Volume 55 , Issue 4 , November 1988 , pp. 529 - 538
Copyright
Copyright © Proprietors of Journal of Dairy Research 1988

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References

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