Enzymatic Hydrolysis Coupled with Autoclaving-cooling Cycles for the Preparation of Resistant Starch

Maize starch was used as raw material to prepare resistant starch by enzyme method coupled with autoclaving–cooling cycles.Hydrolysis and debranching degree of starch,amylose content,resistant starch content and thermodynamic stability were detected in the experiment.The thermodynamic characteristics,particle morphology of resistant starch were analyzed by differential scanning calorimeter(DSC) and scanning electron microscope(SEM),respectively.The results showed that the hydrolysis degree of starch was increased significantly after enzymolysis of thermostable α-amylase.Resistant starch content of coupled thermostable α-amylase with autoclaving-cooling cycles was 10.51% to 12.16%.Debranching degrees,resistant starch and amylose content were declined significantly with autoclaving-cooling cycles increasing before digestion of pullulanase,but thermal stability of the resistant starch was increased.The resistant starch content reached the highest value(17.94%) after digestion of pullulanase before three times processing of autoclaving-cooling cycles.Gelatinization peak temperature of resistant starch was from 119.5 to 121.1 ℃ ℃.The gelatinization enthalpy was increased with resistant starch content increasing,and the granule shape of resistant starch was of irregular gravel type.