The high molecular weight and large particle size and high crystallinity of starch increase gelatinization temperature and retrogradation in glutinous rice.

The gelatinization and retrogradation properties of glutinous rice starch are important factors that affect its quality. In this study, the thermal properties, viscosity properties and retrogradation of starch from 152 natural glutinous varieties were investigated, and further explored the effects of starch structure on gelatinization temperature (GT) and retrogradation. The results demonstrated a strong positive linear correlation between thermal properties and retrogradation of glutinous rice. The high molecular weight, high crystallinity and large particle size of starch have significant positive effects on the thermal properties and retrogradation of amylopectin. Varieties of glutinous rice with high molecular weight starch, large starch particle sizes, and high crystallinity exhibited high GT and retrogradation rates (R%). Additionally, there was a significantly negative correlation between the range of gelatinization temperature and gelatinization enthalpy in raw starch, while a larger temperature range in retrograded starch corresponded to greater gelatinization enthalpy. The recrystallization of retrograded starch exhibited higher crystal heterogeneity and a broader range of melting points compared to raw glutinous starch. These findings provide valuable insights for breeding glutinous rice varieties with desirable retrogradation traits, particularly those with low R%.