Effect of metal salts on α-amylase-catalyzed hydrolysis of broken rice under a moderate electric field.

This study aimed to evaluate the effects of metal salts on α-amylase-catalyzed hydrolysis of broken rice under a moderate electric field (MEF) by monitoring changes in hydrolysis efficiency, temperature, α-amylase activity, starch-metal ion interaction, and the structural and physicochemical properties of hydrolysates. Results showed that metal salts affected the hydrolysis mainly by altering α-amylase activity rather than by inducing thermal effect or interacting with starch. Reducing sugar content reached 125.0 g/L, while α-amylase activity increased by 18.16% when treated with 0.12 mmol/L Ca. Holes on hydrolysates treated with Ca and Mg were larger than those treated with Mn and Cu. No M-O bond was formed after the hydrolysis. The crystallinity was slightly increased with the hydrolysis and the values for Ca- and Mg-treated samples were larger. The water and oil absorption capacity of the hydrolysate treated with Ca was the highest. This study extended the knowledge of the roles of metal ions on MEF-assisted enzymatic hydrolysis and will contribute to the development of an innovative technology for starch modification.