酵素処理による各種澱粉粒の特性改変（第２報） 酵素処理による３種起源の澱粉粒の特性改変

Abstract

Corn, wheat, and potato starches were treated with three enzymes, and features of the degradation including changes in physicochemical properties were studied. The rate of degradation by α-amylase was approximately equal for corn and wheat starches, and less for potato starch. The amount of enzyme adsorbed on the starches was 10-1 to 1.0IU/g. Scanning electron microscopy showed that the number and size of the holes formed on corn starch granules increased during degradation by α-amylase, and that linear erosions and cracks also formed. Narrow, deep hollows were found on the surface of corn starch granules treated by glucoamylase. Corn starch granules treated with β-amylase were degraded less than by α-amylase or glucoamylase, although fine holes formed. Wheat and potato starch granules treated with α-amylase showed collapses, cracks, and erosions. Physicochemical properties were studied by microviscometry. The values for the physicochemical properties tested decreased to different extents in all three kinds of starch during treatment with α-amylase. These values decrease for corn and potato starches treated by α-amylase until about 2% had degraded. These decreases seemed to be caused by the partial degradation of the starch granules and by enzyme adsorption. In corn starch, in particular, partial degradation seemed to have a larger effect in changing the physicochemical properties than enzyme adsorption did. Glucoamylase and β-amylase did not change the physicochemical properties of corn starch.