Structural Studies on Retrograded Normal and Waxy Corn Starches

Abstract

To determine the structure of retrograded starch, 10% solutions of normal-and waxy corn starches were treated by repeated freeze-thaw cycles to obtain extremely retrograded starch samples . These starch samples were examined for the determination of the degree of gelatinization, iodine binding, acid and enzyme hydrolysis etc. The residual carbohydrates after acid and enzyme treatment were completely different from each other in molecular weight and shape, determined by the gel filtration of Toyopearl HW-50. We proposed three different domains (A, B and C) existing in retrograded starch, which are schematically illustrated in the text .