Preparation of porous starch by α-amylase-catalyzed hydrolysis under a moderate electric field

Abstract

Enzymatically-catalytic conversion of starch-based industrial waste into porous materials was enhanced by a moderate electric field (MEF). Changes in the hydrolysis rate, α-amylase activity and starch structure during MEF treatment (0–20 V, 0–400 Hz, room temperature and 0–2 h) were monitored and the hydrolyzed products were characterized by scanning electron microscopy, X-ray diffraction and water/oil adsorption analyses. The results showed that MEF enhanced enzymatic hydrolysis mainly by destroying starch structure, rather than by altering α-amylase activity. The average number of pores of hydrolyzed starch increased when voltage increased from 2 to 15 V, but a further increase of voltage caused the gelatinization of starch, thus making it unfavorable for the preparation of porous materials. The crystallinity of electrically-treated porous starches was decreased by 2.87–5.06%. The water and oil adsorption capacity of the porous starches was much higher than that of their native counterpart. Overall, this study extends the applications of electric field-based techniques in an enzymatic modification of biomaterials.