Abstract:

Four rice cultivars with different amylose content were used to investigate the starch structure and RVA pasting properties in this study. The results showed that differences existed between rice cultivars. Relative crystallinity decreased and setback viscosity increased with increasing amylase content, and there were significant negative and positive correlations between relative crystallinity and amylose content, amylase content and setback viscosity, respectively(r=－0.964*, r=0.997**). Correspondingly, the significant negative correlation of setback viscosity with relative crystallinity was discovered (r=－0.960*). The crystallinity patterns of in four rice starch cultivars showed as typical A type with amylose content ranged from 3.43%–21.65%. Endosperm structure was different between glutinous or low-amylose and non-glutinous or high-amylose rice, and the arrangement and shape were different between the dorsum and abdomen in amyloplast of rice endosperm. The results implied that the shapes and arrangements of starch granule in endosperm might influence the relative crystallinity of rice starch.

Key words: Rice, Amylose content (AC), Paste property, Relative crystallinity