Abstract:To investigate starch fine structure changes during rice storage, five rice cultivars collected from different regions were stored at 35℃ under relative humidity 75% for accelerated storage observation. After rice starch extraction, microstructure, particle size distribution, crystal structure, short-range ordered structure and amylopectin chain length distributions of starch were measured. The results showed that the starch fine structure of five rice cultivars changed with storage time (30, 60 and 90 d). Relative crystallinity of rice starch presented an increasing tendency to different degrees, and rice starch displayed typical A-type crystallization without transformation during storage. The short-ranged ordered structure of rice starch became tighter and more ordered. The percentage of short amylopectin chains (DP 6~12) increased, while the medium and long amylopectin chains (DP 25~36 and DP ≥37) decreased over time. The particle size and size distribution of rice starch insignificantly changed during storage.
