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Electroacoustic determination of size and zeta potential of casein micelles in skim milk

Published online by Cambridge University Press:  01 June 2009

Theresa Wade
Affiliation:
School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia
James K. Beattie
Affiliation:
School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia
William N. Rowlands
Affiliation:
School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia
Mary-Ann Augustin
Affiliation:
CSIRO Division of Food Science and Technology, Melbourne Laboratory, Highett, VIC 3190, Australia

Summary

Measurements of the zeta potential and particle size of casein micelles in skim milk suspensions at natural and lower pH have been made using the technique of electroacoustics. This technique requires no dilution or change of environment of the casein micelles. The zeta potential obtained at natural pH for a commercial skim milk suspension was −18 mV; it became less negative with decreasing pH. The median particle size observed at natural pH for a commercial skim milk suspension was 0·2 εm, in good agreement with previously reported values. The particle size increased as the pH was decreased.

Type
Original Articles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1996

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