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Preparation of dairy products for scanning electron microscopy: etching of epoxy resin-embedded material

Published online by Cambridge University Press:  01 June 2009

Brian E. Brooker
Affiliation:
*National Institute for Research in Dairying (University of Reading), Shinfield, Reading RG2 9 AT, UK
Karen Wells
Affiliation:
*National Institute for Research in Dairying (University of Reading), Shinfield, Reading RG2 9 AT, UK

Summary

Sections (1–5 μm thick) of epoxy resin-embedded cheese curd, yogurt, whipped cream and cream cheese were etched by treatment with warm alcoholic NaOH. Thin specimens were produced which could be metal coated and examined by scanning electron microscopy using accelerating voltages of at least 30 kV without producing charging problems. The images observed were easy to interpret and could be used to produce quantitative results. Although native milk fat globules did not survive the etching process, homogenized milk fat was not adversely affected. Critical point drying of etched sections produced results superior to those obtained by air drying.

Type
Original Articles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1984

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References

REFERENCES

Beeston, B. E. P. 1973 High voltage microscopy of biological specimens, some practical considerations. Journal of Microscopy 98 402416CrossRefGoogle ScholarPubMed
Berkowitz, L. R., Fiorello, O., Kruoer, L. & Maxwell, D. S. 1968 Selective staining of nervous tissue for light-microscopy following preparation for electron microscopy. Journal of Histochemistry and Cytochemistry 16 808814CrossRefGoogle ScholarPubMed
Davies, F. L., Shankar, P. A., Brooker, B. E. & Hobbs, D. G. 1978 A heat-induced change in the structure of milk and its effect on gel formation in yoghurt. Journal of Dairy Research 45 5358CrossRefGoogle Scholar
Graf, E. & Müller, H. R. 1965 Fine structure and whippability of sterilized cream. Milchwissenschaft 20 302308Google Scholar
Harwalkar, V. R. & Kalab, M. 1981 Effect of acidulants and temperature on microstructure, firmness and susceptibility to syneresis of skim milk gels. In Scanning Electron Microcopy III pp. 503513 (Eds Holcomb, D. N. and Kalab, M.). Illinois: Scanning Electron Microscopy Inc.Google Scholar
Henstra, S. & Schmidt, D. G. 1970 On the structure of the fat-protein complex in homogenized cow's milk. Netherlands Milk and Dairy Journal 24 4551Google Scholar
Kalab, M. 1979 Scanning electron microscopy of dairy products: an overview. In Scanning Electron Microscopy III pp. 261272 (Eds Holcomb, D. N. and Kalab, M.). Illinois: Scanning Electron Microscopy Inc.Google Scholar
Kalab, M. 1981 Electron microscopy of milk products: a review of techniques. In Scanning Electron Microscopy III pp. 453472 (Eds Holcomb, D. N. and Kalab, M.). Illinois: Scanning Electron Microscopy Inc.Google Scholar
Kalab, M., Emmons, D. B. & Saroant, A. G. 1976 Milk gel structure. V. Microstructure of yoghurt as related to the heating of milk. Milchwissenschaft 31 402408Google Scholar
Kimbbr, A. M., Brooker, B. E., Hobbs, D. G. & Prentice, J. H. 1974 Electron microscope studies of the development of structure in Cheddar cheese. Journal of Dairy Research 41 389396CrossRefGoogle Scholar
Lane, B. P. & Europa, D. L. 1965 Differential staining of ultrathin sections of Epon-embedded tissues for light microscopy. Journal of Histochemistry and Cytochemistry 13 579582CrossRefGoogle ScholarPubMed
Lange, R. H. & Kegel, B. 1972 Scanning electron microscopy of animal tissues, after embedding in epoxy resin, and dissolving off the embedding medium. Mikroskopie 28 158184Google Scholar
Mayor, H. D., Hampton, J. C. & Rosario, B. 1961 A simple method for removing the resin from epoxyembedded tissue. Journal of Biophysical and Biochemical Cytology 9 909910CrossRefGoogle ScholarPubMed
Ohashi, T., Haga, S., Yamauohi, K. & Olson, N. F. 1983 Scanning electron microscopy of casein micelle networks in milk rennet curd. Japanese Journal of Zootecknical Science 54 479481Google Scholar
Pachter, B. R., Penha, D., Davidowitz, J. & Brienin, G. M. 1973 Technique for examining uncoated specimens in the SEM with light microscope and TEM correlation. In Scanning Electron Microscopy p. 387 (Ed. Johari, O.). Chicago: I.I.T. ResearchGoogle ScholarPubMed
Steffens, W. L. 1978 A method for the removal of epoxy resins from tissue in preparation for scanning electron microscopy. Journal of Microscopy 113 9599CrossRefGoogle ScholarPubMed
Thurley, K. W. & Mouel, W. C. 1974 The etching of thick Araldite-embedded sections for scanning electron microscopy. Journal of Microscopy 101 215218CrossRefGoogle ScholarPubMed
Weibel, E. R., Kistler, G. S. & Scherle, W. F. 1966 Practical stereological methods for morphometric cytology. Journal of Cell Biology 30 2338CrossRefGoogle ScholarPubMed
Williams, M. A. 1977 Quantitative Methods in Biology, Amsterdam: North HollandGoogle Scholar
Wooding, F. B. P. 1971 The structure of the milk fat globule membrane. Journal of Ultrastructure Research 37 388400CrossRefGoogle ScholarPubMed
Yensen, J. 1968 Removal of epoxy resin from histological sections following halogenation. Stain Technology 43 344346Google ScholarPubMed