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RHEOLOGICAL PROPERTIES OF AQUEOUS SOLUTIONS OF THE GUMMY EXUDATE OF ZANTHOXYLUM TESSMANNII
Author(s) -
ORAFIDIYA 'LARA O.
Publication year - 1989
Publication title -
journal of texture studies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.593
H-Index - 54
eISSN - 1745-4603
pISSN - 0022-4901
DOI - 10.1111/j.1745-4603.1989.tb00440.x
Subject(s) - rheology , aqueous solution , viscosity , chemical engineering , adsorption , shear thinning , polyelectrolyte , materials science , chemistry , exudate , chromatography , organic chemistry , polymer , composite material , botany , engineering , biology
Some factors that affect the rheological properties of the aqueous solutions of zanthoxylum gum were studied. The solutions exhibited Newtonian flow at low concentrations, becoming pseudoplastic as concentration increased. It was impossible to obtain a completely wetted mass at concentrations above 25% w/v. The viscosity of the gum solutions reduced irreversibly on storage and when stored at elevated temperature. However, an increase was observed with decrease in storage temperature with the solution turning into a stable gel at 4°C. The gum solutions exhibited characteristics of an acidic polyelectrolyte at dilute concentrations and in the presence of acid and salts. The expected increase in viscosity with added base was not obtained. A thick gel layer formed at interfaces between the gum solution and air, and containers and closures made with polymeric materials. This was attributed to the adsorption and interaction of the gum molecules at these interfaces.