The Effect of Amylose Content from Differing Botanical Sources on the Nonlinear Viscoelastic Properties of Semidilute Solutions of Maize Starches*

The effect of the addition of potato or maize on the shear-thickening behavior of semidilute solutions of maize was examined. The experiments were conducted at 25°C using 90/10 weight–weight dimethyl sulfoxide (DMSO)–water as the solvent. The addition of amylose to maize amylopectin reduced and eventually eliminated the observed shear-thickening behavior of maize amylopectin. When potato amylose was combined with maize amylopectin, the shear-thickening phenomenon was observed up to a total amylose content of 10% by weight. For maize amylose, the shear-thickening behavior was eliminated at an amylose content of 5%. Maize amylose is thus more effective in inhibiting the formation of the structure formed after the shear-thickening region than potato amylose. This result indicates that the amylose obtained from potatoes interacts differently, or entangles differently, with maize amylopectin than does the amylose obtained from maize. © 1999 John Wiley & Sons, Inc.* J Appl Polym Sci 73: 2429–2436, 1999