Amylopectin crystal seeds: Characterization and their effect on amylopectin retrogradation

Abstract

Amylopectin retrogradation greatly affects the overall characteristics of starch. It occurs gradually over a long period of time and the results of its measurement are often subtle. In this study, three types of amylopectin crystal seeds (ACS) were prepared and added to rice amylopectin to enhance the detectability of amylopectin retrogradation. Among the ACS, two crystal seeds with B-type structures increased the relative crystallinity of retrograded amylopectin by a maximum of 4.73% and the retrogradation rate constant from 0.035 up to the maximum 0.045 d−1. These results indicated that these two types of ACS with similar crystal structures increased the nuclei formation during amylopectin recrystallization. The remaining crystal seed had an A-type structure and no significant effect on amylopectin retrogradation. Therefore, it was speculated that pure amylopectin retrograded by forming nuclei with a B-type structure, and the nuclei formed subsequently induced adjacent chains to form the eventual starch crystal.