SDS-sulfite increases enzymatic hydrolysis of native sorghum starches

The sodium dodecyl sulfate (SDS) starch isolation procedure is often used t o remove efficiently the surrounding and surface protein of starch granules in order to obtain a pure starch sample. In this study the changes in enzy matic hydrolysis of sorghum starch granules due to SDS-sulfite solution tre atment were investigated. As SDS-sulfite solution soak time increased, enzy matic hydrolysis rate increased and the Michaelis-Menten pattern of enzymat ic reaction did not change, The degree of this effect differed among starch es from three sorghum cultivars. The effect of SDS-sulfite solution treatme nt on enzymatic hydrolysis became negligible after the treated starch sampl es were partially hydrolyzed. The adsorption of alpha-amylase onto the star ch granules also increased with SDS-sulfite solution treatment and was high ly correlated with hydrolysis rate. The different effects of SDS-sulfite so lution on enzymatic hydrolysis of the three sorghum starches were related t o the properties of the amorphous regions in starch granules.