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.
Keywords: Autoclaving; Enzymatic modification; Glycaemic index; Physicochemical properties; Rice starch.
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