Effect of succinylation on the rheological profile of starch pastes

Rheological properties of native corn and amaranth starches, and the changes therein on succinylation have been evaluated. The degree of substitution (DS) was varied from 0.05 to 0.20 at concentrations up to 5%. A strong shear thinning behavior was observed in all the starch pastes, as described by the power law parameters, i.e. the consistency index, K, and the flow behavior or power law index, n. The effect of concentration and DS on the apparent viscosity is described. Amaranth starch succinates showed a greater shear thinning behavior vis-à-vis corn starch succinates. The bulky hydrophilic succinate group seem to influence the rheological properties.