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Heat stability of milk: influence of dilution and dialysis against water

Published online by Cambridge University Press:  01 June 2009

Patrick F. Fox
Affiliation:
Department of Food Chemistry, University College, Cork, Irish Republic
Catherine M. Hearn
Affiliation:
Department of Food Chemistry, University College, Cork, Irish Republic

Summary

The marked precipitation of Ca phosphate found to occur at ~ pH 6·8 when milk is heated to high temperatures may account for the minimum in the heat coagulation time (HCT)–pH curve at ~ pH 6·8. Dialysis of milk against water for about 3 h converted a normal type A milk to one with type B heat stability characteristics by reducing stability in the region of the HCT maximum while increasing stability in the region of the minimum. Reduction of the concentration of urea, lactose, Na or chloride did not cause these changes and gross micelle structure appeared to be intact following short dialysis as indicated by turbidity and sedimentability. Dilution of milk with water increased stability at the minimum without significantly affecting stability at the maximum. Pre-heating at 80°C for 10 min precluded the effect of dilution but not of dialysis.

Type
Original Articles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1978

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References

REFERENCES

Association of Official Analytical Chemists (1965). Official Methods of Analysis, 10th Edn, p. 15Washington, D.C.: A.O.A.C.Google Scholar
British Standards Institution (1963). B.S. No. 1741.Google Scholar
Davies, D. T. & White, J. C. D. (1966). Journal of Dairy Research 33, 67.CrossRefGoogle Scholar
Fiske, C. H. & Subbarow, Y. (1925). Journal of Biological Chemistry 66, 375.CrossRefGoogle Scholar
Fox, P. F. & Hearn, C. M. (1978). Journal of Dairy Research 45, 159.CrossRefGoogle Scholar
Fox, P. F. & Hoynes, M. C. T. (1975). Journal of Dairy Research 42, 427.CrossRefGoogle Scholar
Herrington, B. L. & Kleyn, D. H. (1960). Journal of Dairy Science 43, 1050.CrossRefGoogle Scholar
Howat, G. R. & Wright, N. C. (1934). Biochemical Journal 28, 1336.CrossRefGoogle Scholar
Kannan, A. & Jenness, R. (1961). Journal of Dairy Science 44, 808.CrossRefGoogle Scholar
McGann, T. C. A. & Pyne, G. T. (1960). Journal of Dairy Research 27, 403.Google Scholar
Morrissey, P. A. (1969). Journal of Dairy Research 36, 343.CrossRefGoogle Scholar
Muir, D. D. & Sweetsur, A. W. M. (1976). Journal of Dairy Research 43, 495.CrossRefGoogle Scholar
Muir, D. D. & Sweetsur, A. W. M (1977). Journal of Dairy Research 44, 249.CrossRefGoogle Scholar
Rose, D. (1961 a). Journal of Dairy Science 44, 430.CrossRefGoogle Scholar
Rose, D. (1961 b). Journal of Dairy Science 44, 1405.CrossRefGoogle Scholar
Rose, D. (1962). Journal of Dairy Science 45, 1305.CrossRefGoogle Scholar
Sweetsur, A. W. M. & White, J. C. D. (1975). Journal of Dairy Research 42, 73.CrossRefGoogle Scholar
Tessier, H. & Rose, D. (1964). Journal of Dairy Science 47, 1047.CrossRefGoogle Scholar