Cereal Chem 68:300-304   |  VIEW ARTICLE

Influence of Poly (Ethylene-co-Acrylic Acid) on the Paste Viscosity and Gel Rheology of Cornstarch Dispersions.

G. F. Fanta and D. D. Christianson. Copyright 1991 by the American Association of Cereal Chemists, Inc. 

The rise in viscosity of aqueous starch suspensions during gelatinization was measured with a Brabender amylograph with and without poly (ethylene-co-acrylic acid) (EAA). Increases in paste viscosity were observed with as little EAA as 0.25-0.50 g/30 g of starch. EAA was added as a 5-10% solution in aqueous ammonium hydroxide, thus producing an alkaline pH during pasting. A similar but smaller increase in viscosity was also observed under near-neutral conditions, brought about by the removal of excess ammonia by evaporation. Gelatinization of starch in the presence of either poly (acrylic acid) or stearic acid caused no increase in viscosity; this is consistent with the theory that EAA increases viscosity by pseudocross- linking starch through formation of helical inclusion complexes with more than one starch macromolecule. Although EAA increases the paste viscosity of aqueous starch dispersions, it reduces the strength of gels formed from starch pastes. Scanning electron micrographs and Fourier transform infrared analyses for EAA suggest that EAA does not promote disruption of starch granules but complexes with starch that has already been solubilized by heating in water.