Study on in vitro digestion and structure change of resistant starch

To prepare corn resistant starch by pullulanase, and establish digestion kinetic model compared with corn starch.Digestion of resistant starch through different time was investigated by X- ray diffraction, differential scanning calorimetry, Fourier transform infrared.The results showed that corn starch was almost hydrolyzed in 2h, hydrolysis rate constant was 2.32h - 1 , higher than resistant starch ( 1.13h - 1 ) .Both crystallinity and enthalpy were increased, which showed that proceed mainly was hydrolysis kinetic.After 2h, crystallinity decreased but showed a disordered change process, amylose was rearrangement and linked by hydrogen bond, the formed polymer can resist amylase hydrolysis.The digestion showed a competition between the kinetics of enzyme hydrolysis and the kinetics of amylose retrogradation.