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Heat stability of milk: influence of modifying sulphydryl-disulphide interactions on the heat coagulation time–pH profile

Published online by Cambridge University Press:  01 June 2009

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

Addition of reducing agents such as 2-mercaptoethanol (2-ME), dithio-threitol and Na sulphite to milk markedly reduced its heat stability at pH values below 7·1. 2-ME reversibly destabilized milk or serum protein-free casein micelle dispersions and promoted the release of κ-casein-rich protein from the micelles. Reduction of either casein micelles or β-lactoglobulin (β-lg) with 2-ME and subsequent blocking of the newly formed –SH groups with N-ethylmaleimide irreversibly reduced the maximum to minimum ratio in the heat stability profile. 2-ME disrupted κ-casein/β-lg complexes and stripped κ-casein from the micelles on heating. The milk or caseinate systems were thus destabilized. Addition of KBrO4 or iodosobenzoate to milk at 5 HIM eliminated the minimum but destabilized milk in the region of the maximum. However, KIO3 at 5 mm had a strong stabilizing effect throughout the pH range 6·5–7·3.

Type
Original Articles
Information
Journal of Dairy Research , Volume 54 , Issue 3 , August 1987 , pp. 347 - 359
Copyright
Copyright © Proprietors of Journal of Dairy Research 1987

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References

REFERENCES

Aoki, T. & Kako, Y. 1984 Influence of 2-mercaptoethanol on heat stability of concentrated whey-protein-free milk and formation of soluble casein. Journal of Dairy Research 51 439–445CrossRefGoogle Scholar
Aoki, T., Suzuki, H. & Imamura, T. 1974 Formation of soluble casein in whey protein-free milk heated at high temperature. Milchwissenschaft 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
Da Vies, 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
Fiat, A. M., Alais, C. & JollèS, P. 1972 The amino-acid and carbohydrate sequences of a short glycopeptide isolated from bovine κ-casein. European Journal of Biochemistry 27 408–412CrossRefGoogle 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
Horwitz, W. (Ed.) 1975 Official Methods of Analysis of the AOAC 12th edn, p. 248. Washington, DC: Association of Official Analytical ChemistsGoogle Scholar
Janolino, V. G. & Swaisgood, H. E. 1975 Isolation and characterization of sulfhydryl oxidase from bovine milk. Journal of Biological Chemistry 250 2532–2538CrossRefGoogle ScholarPubMed
Jenness, R. & Koops, J. 1962 Preparation and properties of a salt solution which simulates milk ultrafiltrate. Netherlands Milk and Dairy Journal 16 153–164Google Scholar
Jue, R., Lambert, J. M., Pierce, L. R. & Traut, R. R. 1978 Addition of sulfhydryl groups to Escherichia coli ribosomes by protein modification with 2-iminothiolane (methyl 4-mercaptobutyrimidate). Biochemistry 17 5399–5406Google Scholar
Kiddy, C. A. 1973 Methods of gel electrophoresis in vertical polyacrylamide beds. In Methods of Gel Electrophoresis of Milk Proteins pp. 14–15 (Ed. Swaisgood, H. E.), Champaign, IL: American Dairy Science AssociationGoogle Scholar
Pepper, L. & Farrell, H. M. 1982 Interactions leading to formation of casein submicelles. Journal of Dairy Science 65 2259–2266CrossRefGoogle Scholar
Rose, D. 1962 Factors affecting the heat stability of milk. Journal of Dairy Science 45 1305–1311CrossRefGoogle Scholar
Singh, H. & Fox, P. F. 1985 a Heat stability of milk: the mechanism of stabilization by formaldehyde. Journal of Dairy Research 52 65–76CrossRefGoogle Scholar
Singh, H. & Fox, P. F. 1985 b Heat stability of milk:pH-dependent dissociation of micellar κ-casein on heating milk at ultra high temperatures. Journal of Dairy Research 52 529–538CrossRefGoogle Scholar
Singh, H. & Fox, P. F. 1987 Heat stability of milk: role of β-lactoglobulin in the pH-dependent dissociation of micellar κ-casein. Journal of Dairy Research 54 In the PressGoogle 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-casein and β-actoglobulin on the heat stability of skimmilk. Journal of Dairy Science 47 1047–1051CrossRefGoogle Scholar
Tran, V. D. & Baker, B. E. 1970 Casein. IX. Carbohydrate moiety of κ-casein. Journal of Dairy Science 53 1009–1012CrossRefGoogle Scholar
Traut, R. R., Bollen, A., Sun, T. T., Hershey, J. W. B., Sundberg, J. & Pierce, L. R. 1973 Methyl 4- mercaptobutyrimidate as a cleavable cross-linking reagent and its application to the Escherichia coli 30S ribosome. Biochemistry 12 3266–3273Google Scholar
Warren, L. 1959 The thiobarbituric acid assay of sialic acid. Journal of Biological Chemistry 234 1971–1975Google Scholar