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Heat stability of milk: pH-dependent dissociation of micellar κ-casein on heating milk at ultra high temperatures

Published online by Cambridge University Press:  01 June 2009

Harjinder Singh  and
Partick F. Fox
Harjinder Singh
Affiliation:
Department of Dairy and Food Chemistry, University College, Cork, Irish Republic,
Partick F. Fox
Affiliation:
Department of Dairy and Food Chemistry, University College, Cork, Irish Republic,
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Summary

Preheating milk at 140 °C for 1 min at pH 6·6, 6·8, 7·0 or 7·2 shifted the heat coagulation time (HCT)/pH profile to acidic values without significantly affecting the maximum stability. Whey proteins (both β-lactoglobulin and α-lactalbumin) co-sedimented with the casein micelles after heating milk at pH < 6·9 and the whey protein-coated micelles, dispersed in milk ultrafiltrate, showed characteristic maxima–minima in their HCT/pH profile. Heating milk at higher pH values (> 6·9) resulted in the dissociation of whey proteins and κ-casein-rich protein from the micelles and the residual micelles were unstable, without a maximum–minimum in the HCT/pH profile. Preformed whey protein–casein micelle complexes formed by preheating (140 °C for 1 min) milk at pH 6·7 dissociated from the micelles on reheating (140 °C for 1 min) at pH > 6·9. The dissociation of micellar-κ-casein, perhaps complexed with whey proteins, may reduce the micellar zeta potential at pH ≃ 6·9 sufficiently to cause a minimum in the HCT/pH profile of milk.

Type
Original Articles
Information
Journal of Dairy Research , Volume 52 , Issue 4 , November 1985 , pp. 529 - 538
Copyright
Copyright © Proprietors of Journal of Dairy Research 1985

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References

REFERENCES

Association of Official Analytical Chemists 1970 Official Methods of Analysis of the AOAC 12th edn p. 248. Washington DC: AOACGoogle Scholar
Aoki, T. & Kako, Y. 1983 Relation between micelle size and formation of soluble casein on heating concentrated milk. Journal of Dairy Research 50 207–213CrossRefGoogle Scholar
Aoki, T., Suzuki, H. & Imamura, T. 1974 Formation of soluble casein in whey protein-free milk heated at high temperatures. Milchiwissenschaft 29 589–594Google Scholar
Aoki, T., Suzuki, H. & Imamura, T. 1975 Some properties of soluble casein in heated concentrated whey protein-free milk. Milchwissenschaft 30 30–35Google Scholar
Burton, H. 1969 Ultra-high-temperature processed milk. Dairy Science Abstracts 31 287–297Google Scholar
Clarke, R. & Nakai, S. 1971 Investigation of κ-αsl-casein interaction by fluorescence polarization. Biochemistry 10 3353–3357CrossRefGoogle ScholarPubMed
Creamer, L. K. & Matheson, A. R. 1980 Effect of heat treatment on the proteins of pasteurized skim milk. New Zealand Journal of Dairy Science and Technology 15 37–49Google Scholar
Davies, D. T. & White, J. C. D. 1966 The stability of milk protein to heat. 1. Subjective measurement of heat stability of milk. Journal of Dairy Research 33 67–81CrossRefGoogle Scholar
Davies, J. M. 1959 Decrease in the heat stability of milk on forewarming. 15th International Dairy Congress London 3 1859–1863Google Scholar
Dunnill, P. & Green, D. W. 1966 Sulphydryl groups and N ⇋ R conformational change in β-lactoglobulin. Journal of Molecular Biology 15 147–151CrossRefGoogle Scholar
Fox, K. K., Harper, M. K., Holsinger, V. H. & Pallansch, M. I. 1967 Effect of high-heat treatment on stability of calcium-caseinate aggregates in milk. Journal of Dairy Science 50 443–450CrossRefGoogle Scholar
Fox, P. F. 1981 Heat stability of milk significance of heat-induced acid formation in coagulation. Irish Journal of Food Science & Technology 5 1–11Google Scholar
Fox, P. F. & Hearn, C. M. 1978 Heat stability of milk: influence of denaturable proteins and detergents on pH sensitivity. Journal of Dairy Research 45 159–172CrossRefGoogle Scholar
Fox, P. F. & Hoynes, M. C. T. 1975 Heat stability of milk: influence of colloidal calcium phosphate and β-lactoglobulin. Journal of Dairy Research 42 427–435CrossRefGoogle Scholar
Fox, P. F. & Hoynes, M. C. T. 1976 Heat stability characteristics of ovine, caprine and equine milks. Journal of Dairy Research 43 433–442CrossRefGoogle Scholar
Garnier, J. 1967 Extension of the continuous variation method to protein interactions: αsl- and β-caseins association with κ-casein. Biopolymers 5 473–475CrossRefGoogle Scholar
Jenness, R. & Koops, J. 1962 Preparation and properties of salt solutions which simulate milk ultrafiltrate. Netherlands Milk & Dairy Journal 16 153–164Google Scholar
Kiddy, C. A. 1975 Methods of gel electrophoresis in vertical polyacrylamide beds. In Methods of Gel Electrophoresis of Milk pp. 14–15 (Ed. Swaisgood, H. E.). American Dairy Science AssociationGoogle Scholar
Kudo, S. 1980 The heat stability of milk: formation of soluble proteins and protein depleted micelles at elevated temperatures. New Zealand Journal of Dairy Science & Technology 15 255–263Google Scholar
Mckenzie, H. A. 1971 β-Lactoglobulins. In Milk Proteins. Chemistry & Molecular Biology vol. II pp. 257–330 (Ed. McKenzie, H. A.). New York: Academic PressCrossRefGoogle Scholar
Morr, C. V. 1969 Protein aggregation in conventional and ultra-high temperature heated skim milk. Journal of Dairy Science 52 1174–1180CrossRefGoogle Scholar
Morrissey, P. A. 1969 a The heat stability of milk as affected by variations in pH and milk salts. Journal of Dairy Research 36 343–351CrossRefGoogle Scholar
Morrissey, P. A. 1969 b Influence of preheating on heat stability of milk and similar systems. Irish Journal of Agricultural Research 8 201–205Google Scholar
Morrissey, P. A. & O'mahony, F. 1976 Heat stability of forewarmed milks: influence of κ-casein, serum proteins and divalent cations. Journal of Dairy Research 43 267–274CrossRefGoogle Scholar
Mozhaev, V. V. & Martinek, K. 1984 Review: Structure-stability relationship in proteins: new approaches to stabilizing enzymes. Enzymes and Microbial Technology 6 50–59CrossRefGoogle Scholar
Newstead, D. F. 1977 Heat stability of evaporated milk. New Zealand Journal of Dairy Science & Technology 50th Jubilee Conference Special Issue 89–93Google Scholar
Newstead, D. F., Sanderson, W. B. & Baucke, A. G. 1975 The effects of heat treatment and pH on the heat stability of recombined evaporated milk. New Zealand Journal of Dairy Science & Technology 10 113–118Google Scholar
Pepper, L., Hip, N. J. & Gordon, W. G. 1970 Effects of modification of e-amino groups on the interaction of κ- and αsl-caseins. Biochimica el Biophysica Acta 207 340–346CrossRefGoogle Scholar
Pyne, G. T. & Mchenry, K. A. 1955 The heat coagulation of milk. Journal of Dairy Research 22 60–68CrossRefGoogle Scholar
Rose, D. 1961 a Variations in the heat stability and composition of milk from individual cows during lactation. Journal of Dairy Science 44 430–441CrossRefGoogle Scholar
Rose, D. 1961 b Factors affecting the pH-sensitivity of the heat stability of milk from individual cows. Journal of Dairy Science 44 1405–1413CrossRefGoogle Scholar
Rose, D. 1962 Factors affecting the heat stability of milk. Journal of Dairy Science 45 1305–1311CrossRefGoogle Scholar
Sawyer, W. H. 1969 Complex between β-lactoglobulin and κ-casein. A review. Journal of Dairy Science 52 1347–1353CrossRefGoogle ScholarPubMed
Singh, H. & Fox, P. F. 1985 Heat stability of milk: the mechanism of stabilization by formaldehyde. Journal of Dairy Research 52 65–76CrossRefGoogle Scholar
Shalabi, S. I. & Fox, P. F. 1982 Heat stability of milk: influence of modification of lysine and arginine on heat stability-pH profile. Journal of Dairy Research 49 607–617CrossRefGoogle ScholarPubMed
Sweetsur, A. W. M. & Muir, D. D. 1981 Role ofcyanate ions in the urea-induced stabilization of the caseinate complex in skim milk. Journal of Dairy Research 48 163–166CrossRefGoogle Scholar
Sweetsur, A. W. M. & White, J. C. D. 1974 Studies on the heat stability of milk protein. 1. Interconversion of type A and type B milk heat-stability curves. Journal of Dairy Research 41 349–358CrossRefGoogle Scholar
Tessier, H. & Rose, D. 1964 Influence of κ-easein and β-lactoglobulin on the heat stability of skim milk. Journal of Dairy Science 47 1047–1051CrossRefGoogle Scholar
Warren, L. 1959 The thiobarbituric acid assay of sialic acids. Journal of Biological Chemistry 234 1971–1975CrossRefGoogle ScholarPubMed
Webb, B. H. & Bell, R. W. 1942 The effect of high-temperature short-time forewarming of milk upon the heat stability of its evaporated product. Journal of Dairy Science 25 301–311CrossRefGoogle Scholar