Modification of starch using Cyclomaltodextrinase from alkalophillic Bacillus sp.I-5

Abstract

A Cyclomaltodextrinase (CDase I-5) was isolated from alkalophillic Bacillus sp. I-5. CDase has been known to have a specific activity to degrade amylose in starch. The proportion of amylose and amylopectin in starch can be altered by enzymatic modification to produce low-amylose starch products. CDase was reacted with starch and the reaction products were analyzed with size exclusion chromatography and thin layer chromatography. In order to analyze the specificity of CDase to various substrates, the CDase was reacted with amylose and amylopectin and compared. The results indicated that it had specific hydrolysis activity to amylose but hardly affected amylopectin. The side chain length distributions of amylopectin were also analyzed with anion exchange chromatography. The enzyme was employed to produce low amylose rice and potato starch. The retrogradation of the enzyme-treated starch was measured by DSC after stored at 4 oC for 7days. The enzyme-treated starch show significantly slower retrograde compared to control samples