Hostname: page-component-848d4c4894-xm8r8 Total loading time: 0 Render date: 2024-06-20T00:53:01.706Z Has data issue: false hasContentIssue false

Hydration of casein micelles: kinetics and isotherms of water sorption of micellar casein isolated from fresh and heat-treated milk

Published online by Cambridge University Press:  01 June 2009

Max Rüegg
Affiliation:
Federal Dairy Research Institute, CH-3097 Liebefeld-Berne, Switzerland
Madeleine Lüscher
Affiliation:
Department of Inorganic and Physical Chemistry, University of Berne, GH-3012 Berne, Switzerland

Summary

Water vapour sorption isotherms of casein micelles prepared from raw milk and various heat-treated milks were determined. The equilibrium water contents of the heated preparations were markedly lower than that of the raw-milk casein over the whole range of vapour pressures studied. An analysis of the sorption isotherms in the relative vapour pressure range 0·1–0.45, according to the Brunauer, Emmett & Teller (1938) equation, showed that there were significant differences between preparations in the computed monolayer contents. Differences in the rates of water sorption were also observed between the different preparations.

As judged from the amount of absorbed water, the influence of the heating methods could be ranked in the order: HTST (92 °C) ≃ UHT (direct) <UHT (indirect) < HTST (72 °C).

Type
Section D. Casein Micelles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1979

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

Blanc, B., Baer, A. & Rüegg, M. (1977). Schweizerische Milchwirtschaftliche Forschung 6, 21.Google Scholar
Bolliger, W., Gál, S. & Signer, R. (1972). Helvetica Chimica Acta 55, 2659.Google Scholar
Brunauer, S., Emmett, P. H. & Teller, E. (1938). Journal of the American Chemical Society 60, 309.Google Scholar
Crank, P. & Park, G. S. (1968). Diffusion in Polymers. London: Academic Press.Google Scholar
Elfagm, A. A. & Wheelock, J. V. (1977). Journal of Dairy Research 44, 367.Google Scholar
Gál, S. (1975). In Water Relations of Foods, p. 139. (Ed. Duckworth, R. B..) London: Academic Press.CrossRefGoogle Scholar
Guy, E. J., Vettel, H. E. & Pallansch, M. J. (1967). Journal of Dairy Science 50, 828.Google Scholar
Kuntz, I. D. & Kauzmann, W. (1974). In Advances in Protein Chemistry, p. 239. (Eds Anfinsen, C. B., Edsall, J. T. and Richards, F. A..) London: Academic Press.Google Scholar
Morr, C. V. (1975). Journal of Dairy Science 58, 977.CrossRefGoogle Scholar
Rüegg, M. & Blanc, B. (1976). Journal of Dairy Science 59, 1019.CrossRefGoogle Scholar
Rüegg, M. & HÄni, H. (1975). Biochimica et Biophysica Acta 400, 17.CrossRefGoogle Scholar