Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-23T06:51:14.787Z Has data issue: false hasContentIssue false

Chemical changes in ultra-heat-treated milk during storage: I. Hydrolysis of casein by incubation with pronase and a peptidase mixture

Published online by Cambridge University Press:  01 June 2009

A. B. Möller
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading, RG2 9AT
A. T. Andrews
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading, RG2 9AT
G. C. Cheeseman
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading, RG2 9AT

Summary

Casein samples from untreated milk and stored ultra-heat-treated (UHT) milk were hydrolysed with pronase (protease ex Streptomyces griseus K-1) and subsequently with a mixture of peptidases prepared from the microsomal fraction of hog kidneys. Incubation of casein from unheated milk with pronase alone hydrolysed 70–80% of peptide bonds involving Ile, Leu, Tyr, Phe and His residues; other amino acids were released less well and proline hardly at all. The pronase/peptidase treatment resulted in 90–100% hydrolysis of peptide bonds involving all amino acids, including proline.

Caseins from stored UHT milks were more resistant to proteolysis than casein from unheated milk. Reduced release of all amino acids was observed from samples taken after storage at 37 °C for 12 months or longer and for Lys, Arg and Asn residues from samples taken after storage at 30 °C for 14 months. Resistance to proteolysis was attributed to the Maillard reaction between milk proteins and lactose during storage of UHT milk.

Type
Original Articles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1977

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Andrews, A. T. (1975). Journal of Dairy Research 42, 89.CrossRefGoogle Scholar
Andrews, A. T. & Cheeseman, G. C. (1971). Journal of Dairy Research 38, 193.Google Scholar
Andrews, A. T. & Cheeseman, G. C. (1972). Journal of Dairy Research 39, 395.CrossRefGoogle Scholar
Bensusan, H. B., Dixit, S. N. & McKnight, S. D. (1971). Biochimica et Biophysica Acta 251, 100.CrossRefGoogle Scholar
Birkeland, A. J. & Christensen, T. B. (1975). Journal of Carbohydrates, Nucleosides and Nucleotides 2, 83.Google Scholar
Carpenter, K. J., & Booth, V. H. (1973). Nutrition Abstracts and Reviews 43, 424.Google Scholar
Finot, P. A. (1973). In Proteins in Human Nutrition, p. 501. (Eds Porter, J. W. G. and Rolls, B. A..) New York: Academic Press.Google Scholar
Folch, J., Lees, M. & Sloane Stanley, G. H. (1957). Journal of Biological Chemistry 226, 497.Google Scholar
Goldstone, A. & Koenig, H. (1974). Biochemical Journal 141, 527.Google Scholar
Greenstein, J. P. & Winitz, M. (1961). Chemistry of the Amino Acids, vol. 3, p. 1932. New York: Wiley.Google Scholar
Henry, K. M., Kon, S. K., Lea, C. H. & White, J. C. D. (1948). Journal of Dairy Research 15, 292.CrossRefGoogle Scholar
Hill, R. L. & Schmidt, W. R. (1962). Journal of Biological Chemistry 237, 389.Google Scholar
Lyster, R. L. J. (1972). Journal of Dairy Reserach 39, 279.Google Scholar
Matsumura, Y., Nakanishi, T., Iizuka, M. & Yamamoto, T. (1975). Agricultural and Biological Chemistry 39, 379.Google Scholar
Möller, A. B., Andrews, A. T. & Cheeseman, G. C. (1977 a). Journal of Dairy Research 44, 267.CrossRefGoogle Scholar
Möller, A. B., Andrews, A. T. & Cheeseman, G. C. (1977 b). Journal of Dairy Research 44, 277.Google Scholar
Narahashi, Y. (1970). Methods in Enzymology 19, 651.Google Scholar
Reynolds, T. M. (1969). Symposium on Foods. Carbohydrates and their Roles p. 219. (Ed. Schultz, H. W..) Westport, Conn.: AVI Publishing Co.Google Scholar
Rosen, H. (1957). Archives of Biochemistry and Biophysics 67, 10.Google Scholar
Sato, T. & Iijima, T. (1974). Journal of Biochemistry 75, 1173.Google Scholar