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

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