The Morphological Characteristics and Physical Properties of Porous Corn Starch Hydrolyzed by Mixture of α-Amylase and Glucoamylase

This research was conducted to evaluate the effect of $\alpha$-amylase and glucoamylase mixture at various hydrolysis time (0,4,6,8 and 12 hours) to morphological characteristics and physical properties of porous corn starch granules. Scanning Electron Microscopy (SEM) showed the number and size of holes on the surface of starch granules increased with hydrolysis time; moreover, starch granule structure was broken at 8 and 12 hours. The hydrolyzed level of starch granules was increased gradually with reaction time; the highest hydrolysis value was 63.534% in 12 hours of reaction. The results indicated that porous starch had higher adsorption capacity than native starch which was showed in higher oil and water holding ability. Additionally, swelling and solubility of porous corn starch were increased with the prolonging of hydrolysis time and higher than that of native starch samples. Color value tended to increase with increasing hydrolysis time; however, the difference was very small. The results also indicated that viscosity and transmittance of the hydrolyzed starch sample decreased as the hydrolysis time increased as well as lower than native starch. Thus, porous corn starch could be a potential ingredient in the food field.