Differences in Retrogradation Characteristics of Pregelatinized Rice Starch Prepared Using Different Water Content

Abstract Pregelatinized starch improves the properties of natural starch. In this study, differences in retrogradation characteristics of pregelatinized rice starch prepared using different water content are investigated based on their thermal properties, recrystallization, and short‐range ordered structure. The results show that the difference in water content during gelatinization is one of the factors that affects the retrogradation rate of pregelatinized starch. With a decrease in water content during the preparation of pregelatinized starch, the enthalpy, relative crystallinity, and the 1047 cm−1/1022 cm−1 ratio of retrogradation starch shows an upward trend. This is mainly because the different water content affects the amylose content of insoluble starch in pregelatinized starch. For pregelatinized starch, the higher amylose content in precipitate (insoluble pregelatinized starch) is more likely to cause intermolecular aggregation to promote recrystallization and the formation of an ordered structure. The findings also indicate that soluble starch and leached amylose could participate in starch retrogradation with the migration of water. Therefore, the high amylose content of the insoluble component and the existence of leached amylose in pregelatinized rice starch are found to have positive effects on starch retrogradation.