SDS-sulfite increases enzymatic hydrolysis of native sorghum starches

Abstract

The sodium dodecyl sulfate (SDS) starch isolation procedure is often used to remove efficiently the surrounding and surface protein of starch granules in order to obtain a pure starch sample. In this study the changes in enzymatic hydrolysis of sorghum starch granules due to SDS-sulfite solution treatment were investigated. As SDS-sulfite solution soak time increased, enzymatic hydrolysis rate increased and the Michaelis-Menten pattern of enzymatic reaction did not change. The degree of this effect differed among starches from three sorghum cultivars. The effect of SDS-sulfite solution treatment on enzymatic hydrolysis became negligible after the treated starch samples were partially hydrolyzed. The adsorption of α-amylase onto the starch granules also increased with SDS-sulfite solution treatment and was highly correlated with hydrolysis rate. The different effects of SDS-sulfite solution on enzymatic hydrolysis of the three sorghum starches were related to the properties of the amorphous regions in starch granules. © WILEY-VCH Verlag GmbH, 1999.