Abstract:The common corn starch was applied as raw material to prepare the slowly digestible starch (SDS) by using β-amylase and transglucosidase, and the physicochemical properties of the SDS were also investigated. The content of SDS was up to 16.37% with addition of 20 mL β-amylase and 20 mL transglucosidase by stirring for 4 h and 12 h, respectively. The position of maximum absorption peak of starch samples binding iodine shifted obviously with increasing SDS content. Analysis by differential scanning calorimeter showed that the onset melting temperatures, the peak temperatures, terminated temperatures and the temperature differences between beginning and ending of SDS were improved significantly and its thermal stabilities were enhanced, resulting in more difficulty for starches to gelatinize. Compared to the native corn starch displayed “A” typical diffraction pattern, no crystal structure was found for all samples modified by enzymes which represented sharp diffraction peaks at 2?=19.8° and diffuse diffraction peaks at 2?=13.1?. Scanning electron micrographs revealed that all enzyme-treated samples had more irregular fragments without granular structures as native starch.
