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T. A. Dyakina, S. R. Derkatch, S. M. Levachev
Concentrated
Gelatin/Lecithin Emulsions: Rheological Properties
Abstract
Rheological properties of the
concentrated heptane-in-water emulsions (content of dispersed phase j = 0.64 ё 0.80%) have been investigated. The aqueous phase
contains biopolymer (gelatin) and natural phospholipid lecithin. Using the
method of rotational (with controlled shear rate) viscosimetry it has been
shown that the concentrated emulsions reveal the properties of visco-plastic
material under shear deformation. The rheological behavior of emulsions within
the non-linear viscous range is concerned with Hershel-Bulkley model and Casson
model. Addition of phospholipid in the system being accompanied by its
association with gelatin leads to the decrease of yield stress and the increase
of plastic viscosity in comparison with the concentrated emulsions of gelatin.
Values of the rheological parameters change droningly under the increase of
lecithin concentration. Quantitative assessment of the individual contact
strength between the drops covered with the adsorption layers of
gelatin-phospholipid complexes has been carried out.
Copyright (C) Chemistry Dept., Moscow State University, 2002
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