Effect of Ultrasonic Treatment Combined with Enzymatic Hydrolysis on the Multilevel Structure and Adsorption Properties of Maize Starch

In order to explore an effective method to improve the adsorption property of maize starch granules, ultrasonic pretreatment at different temperatures (0, 25, 45, and 65 ℃) below the gelatinization temperature combined with α-amylase was used to modify maize starch. The results showed that after ultrasonic pretreatment, the surface of starch granules became rough with grooves on it. The molecular mass, relative crystallinity and short-range molecular order of the starch samples were significantly decreased (P < 0.05). Compared with single enzymatic hydrolysis, the combinatorial treatment increased the specific surface area and pore capacity of starch consequently improving its adsorption performance. With an increase in the pretreatment temperature from 0 to 65 ℃, the water- and oil-adsorbing capacities of starch granules subjected to the combinatorial treatment increased from 114.71% and 142.16% to 144.77% and 189.70%, respectively. Therefore, ultrasonic treatment at high temperature below the gelatinization temperature combined with α-amylase could be an effective method to prepare a green and high efficiency starch-based adsorbent. This study will be helpful for better understanding of the mechanism by which ultrasonic treatment promotes the enzymatic hydrolysis of starch and will provide a theoretical basis for the development of high-efficiency starch-based adsorbents.