Preparation and structural characterization of resistant starch from rice by dual enzyme method

The paper has taken rice starch as raw material for study on aspects as preparation, digestibility and structural characterization of the resistant starch (RS). Rice RS preparation conditions were researched by single factor experiment; digestibility was studied by anti-enzymatic experiment; the physicochemical of the starches were studied by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and x-ray diffraction (X-RD). Optimum condition is pH 5.5, temperature 80°C, reaction time 40 min and enzyme amount 4 u/g. On the condition, the RS content was 45.2%. The anti-enzymatic of dual enzymatic modified starch has more significant anti-hydrolysis performance than single enzymatic modified starch and heat-moisture modified starch. The hydrolysis rate of dual enzymatic modified starch after 24 h was 8.02%. DSC, SEM and X-RD analysis showed that the dual enzymatic modified RS has high enthalpy, compact structure of space and high crystalline. This indicates that the dual enzyme modified RS has high digestibility.