Hostname: page-component-cd9895bd7-dzt6s Total loading time: 0 Render date: 2024-12-26T06:59:03.314Z Has data issue: false hasContentIssue false
  • English
  • Français

Intermicellar relationships in rennet-treated separated milk: I. Preparation of representative electron micrographs

Published online by Cambridge University Press:  01 June 2009

Margaret L. Green ,
David G. Hobbs  and
Steven V. Morant
Margaret L. Green
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading, RG2 9AT
David G. Hobbs
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading, RG2 9AT
Steven V. Morant
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading, RG2 9AT
Get access Rights & Permissions [Opens in a new window]

Summary

Separated milk was treated with rennet at 30 °C for known proportions of the visually-determined clotting time. Samples were fixed with glutaraldehyde, which inhibited aggregation of casein micelles, mixed with agar, and stained sections examined. Bias in the preparation of the electron micrographs was minimized by replication, particularly in the early stages of sample preparation, and, for thin (60–90 nm) sections, by systematic selection of the areas examined.

Whole casein micelles, viewed in stereo micrographs of thick (about 1 μm) sections, had open, diffuse structures and their appearance did not change on treatment with rennet. Micrographs of thick sections taken at 90° to each other showed that casein micelles form a network-type of gel, with the same structure in all dimensions. Counts of micelles larger than about 20 nm diam. in fields of thin sections showed that each of 3 sets of fields was similar and representative for each sample. The number of micelles/μm2 appeared to increase between 60 and 130 % of the clotting time, but this change was not statistically significant.

Type
Original Articles
Information
Journal of Dairy Research , Volume 45 , Issue 3 , October 1978 , pp. 405 - 411
Copyright
Copyright © Proprietors of Journal of Dairy Research 1978

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

Baud, C.-A.Morard, J.-C. & Pernoux, E. (1951). Comptes Rendus Hebdomadaires des Séances de I' Acádemie des Sciences 233, 276.Google Scholar
Buchheim, W. & Welsch, U. (1973). Netherlands Milk and Dairy Journal 27, 163.Google Scholar
Calapaj, G. G. (1968). Journal of Dairy Research 35, 1.CrossRefGoogle Scholar
Carroll, R. J., Thompson, M. P. & Melnychyn, P. (1971). Journal of Dairy Science 54, 1245.CrossRefGoogle Scholar
Carroll, R. J., Thompson, M. P. & Nutting, G. C. (1968). Journal of Dairy Science 51, 1903.CrossRefGoogle Scholar
Favakd, P. & Carasso, N. (1973). Journal of Microscopy 97, 59.Google Scholar
Ferry, J. D. (1948). Advances in Protein Chemistry 4, 1.CrossRefGoogle Scholar
Green, M. L., Hobbs, D. G., Morant, S. V. & Hill, V. A. (1978). Journal of Dairy Research 45, 413.CrossRefGoogle Scholar
Henstra, S. & Schmidt, D. G. (1970). Proceedings of 8th International Congress on Electron Microscopy, Grenoble 1, 389.Google Scholar
Hostettler, H. & Imhof, K. (1952). Landwirtschaftliches Jahrbuch der Schweiz 66, 307.Google Scholar
Kalab, M., Emmons, D. B. & Sargant, A. G. (1976). Milchwissenschaft 31, 402.Google Scholar
Kalab, M. & Harwalkar, V. R. (1973). Journal of Dairy Science 56, 835.CrossRefGoogle Scholar
Kellenburger, E., Ryter, A. & Séchaud, J. (1958). Journal of Biophysical and Biochemical Cytology 4, 671.CrossRefGoogle Scholar
Kimber, A. M., Brooker, B. E., Hobbs, D. G. & Prentice, J. H. (1974). Journal of Dairy Research 41, 389.CrossRefGoogle Scholar
Knoop, A. M., Knoop, E. & Wiechen, A. (1973). Netherlands Milk and Dairy Journal 27, 121.Google Scholar
Knoop, A. M. & Peters, K. H. (1975). Kieler Milchwirtschaftliche Forschungsberichte 27, 227.Google Scholar
Norrish, K. (1954). Discussions of the Faraday Society 18, 120.CrossRefGoogle Scholar
Peachey, L. D. (1958). Journal of Biophysical and Biochemical Cytology 4, 233.CrossRefGoogle Scholar
Peters, I.I. & Dietrich, J. W. (1954). Texas Journal of Science 6, 442.Google Scholar
Rüegg, M. & Blanc, B. (1972). Schweizerische Milchwirtschaftliche Forschung 1, 1.Google Scholar
Salyaev, R. K. (1968). Pre-Congress Abstracts, 4th European Regional Conference on Electron Microscopy 2, 37.Google Scholar
Schmidt, D. G. & Buchheim, W. (1970). Milchwissenschaft 25, 596.Google Scholar
Schmidt, D. G., Walstra, P. & Buchheim, W. (1973). Netherlands Milk and Dairy Journal 27, 128.Google Scholar
Shimmin, P. D. & Hill, R. D. (1964). Journal of Dairy Research 31, 121.CrossRefGoogle Scholar
Weibel, E. R., Kistler, G. S. & Scherle, W. F. (1966). Journal of Cell Biology 30, 23.CrossRefGoogle Scholar