Impact of Enzyme Modification on Physicochemical Properties of Oat Flake and Starch

Abstract

Oat flakes are modified with alpha (alpha)-amylase and a combination of alpha-amylase and cellulase (alpha-amylase/cellulase) to determine the effect of enzyme modification on the quality of oat flakes and physicochemical properties of oat starch. Enzyme modification using alpha-amylase and cellulase increases the water absorption capacity and decreases the hardness and adhesiveness of oat flakes by degrading long polysaccharide chains. The molecular weight of oat starch modified with alpha-amylase and alpha-amylase/cellulose is lower than that of native oat starch. Moreover, the depolymerization of starch molecules is more notable in starch modified with alpha-amylase/cellulase than in starch modified with alpha-amylase alone. alpha-Amylase treatment during oat flake processing causes the loss of peak viscosity, while alpha-amylase/cellulase treatment results in the loss of both peak and final viscosity of oat starch. In addition, enzyme modification with alpha-amylase/cellulase reduces the content of amylose-lipid complex. Solubility and swelling power are also significantly increased in alpha-amylase/cellulase-modified oat starch. These results indicate that the modification of oat flakes with alpha-amylase and cellulase induces changes in starch structure, thereby affecting physicochemical properties of oat starch and quality of flakes.