Influence of glass transition temperature on rate of rice starch retrogradation during low-temperature storage

Abstract

An increasing amount of research suggests a relationship between the glass-transition temperature (T g) and the optimum storage temperature for a frozen food. In addition, the T g for a frozen food is related to the cooling rate through the temperature range of phase transition for water. The objectives of this study were to investigate the influence of T g on the rate of starch retro-gradation during low-temperature storage. Rice starch with 65% w/w water content was heated to obtain starch gel as a model food. The influences of cooling rate, storage temperature and time on rate of retrogradation were evaluated. Differential scanning calorimetry was used to measure the T g and the enthalpy during retrogradation. Results indicated that the retrogradation rate during storage was reduced at a slower cooling rate. The retrogradation rates at storage temperatures above T g were higher than at storage temperatures below T g. © Copyright 2005, Blackwell Publishing All Rights Reserved.