Modification of rice starch using a combination of autoclaving and triple enzyme treatment: Structural, physicochemical and digestibility properties.

It is highly desirable to improve the physicochemical properties and nutritional functions of rice starch. In this study, the structural, physical and chemical properties and digestibility of autoclaving-modified starch (A-MS), autoclaving/pullulanase-modified starch (A/PUL-MS), autoclaving/sequential three enzymatic (β-amylase → transglucosidase → pullulanase)-modified starch (A/STE-MS) and native rice starch (NRS) were compared. The results showed that compared to NRS, the structure of A/STE-MS granules became dense, and the short-chain ratio (43.17%, DP ≤ 6) was significantly increased. A/PUL-MS and A/STE-MS had significantly higher apparent amylose content (38.39% and 33.78%, respectively) and thermal stability. NRS and A/PUL-MS were A-type and B-type crystalline, respectively, while A-MS and A/STE-MS were V-type crystalline. A/STE-MS had higher swelling and solubility indices and lower apparent viscosity. In addition, A/STE-MS had a lower (62.9) glycaemic index (GI) than native rice starch and other modified starches. This study provides a new perspective for the development of the modified rice starch industry and low GI functional rice starch-based products.