Characterization and Prebiotic Effect of the Resistant Starch from Purple Sweet Potato

Purple sweet potato starch is a potential resource for resistant starch production. The effectsof heat-moisture treatment (HMT) and enzyme debranching combined heat-moisture treatment(EHMT) on the morphological, crystallinity and thermal properties of PSP starches were investigated.The results indicated that, after HMT or EHMT treatments, native starch granules with smoothsurface was destroyed to form a more compact, irregular and sheet-like structure. The crystallinepattern was transformed from C-type to B-type with decreasing relative crystallinity. Due to strongercrystallites formed in modified starches, the swelling power and solubility of HMT and EHMT starchwere decreased, while the transition temperatures and gelatinization enthalpy were significantlyincreased. In addition, HMT and EHMT exhibited greater effects on the proliferation of bifidobacteriacompared with either glucose or high amylose maize starch.