Retrogradation of waxy cornstarch studied by DSC

摘要

The retrogradation process of the biphasic endotherms Gr and M1 r for waxy cornstarch was systematically investigated using differential scanning calorimetry (DSC). The high temperature endotherm M1 r developed significantly within 2-5 h, while the retrograded endotherm Gr appeared after 5 h storage and increased with time. The single endotherm Gr was separated using an analytical software, and the enthalpy was found to be ~36% of the total enthalpy of the retrograded starch. Compared to normal cornstarch (~77% amylopectin content), the final retrogradation ratio of the waxy cornstarch was higher. Both the waxy and normal cornstarches investigated showed a similar pattern of retrogradation process, which developed quickly in the initial stage (up to1 day) and then gradually came to a near-constant value in the second stage (from 1 to 20 days).