Relationship between structure and functional properties of normal rice starches with different amylose contents.

The structures (morphology, molecule, and crystallinity) and functional properties (gelatinization, hydrolysis, and in vitro digestion) of normal rice starches with different amylose contents were investigated and their relationships were analyzed. The results showed that the morphology, granule size, and crystalline type did not significantly change among rice starches. The molecular structure (amylose content, amylopectin branch-chain content, and amylopectin branching degree) and crystalline structure (relative crystallinity, IR ratio of 1045/1022 cm(-1), lamellar peak intensity, and lamellar distance) significantly varied among rice starches, which resulted in different functional properties. The gelatinization temperature and water solubility were significantly positively correlated with amylose content but significantly negatively correlated with amylopectin short branch-chain. The swelling power, hydrolysis and in vitro digestion were significantly positively correlated with amylopectin short branch-chain, relative crystallinity, IR ratio of 1045/1022 cm(-1), and lamellar peak intensity but significantly negatively correlated with amylose content and lamellar distance.