Physicochemical modification of native and extruded wheat flours by enzymatic amylolysis

Abstract

Enzymatic hydrolysis could be an alternative way to modify flour functionality. The effect of two different enzymes, α-amylase and amyloglucosidase, and their combination on microstructure, oligosaccharide content, crystalline order, pasting, gel hydration, and colour properties of native and extruded wheat flours was investigated. Micrographs showed different mechanisms of actuation of the different enzymes on native and extruded flours, achieving greater than 300% and 500% increases of glucose and maltose contents, respectively, in extruded flours compared with their native counterparts. Native flours displayed higher values of water absorption capacity and swelling power than extruded flours. Flours treated by a combination of amylase and amyloglucosidase showed low swelling power. Regarding colour, native flours were darker and more reddish than extruded flours, whereas flours treated by amyloglucosidase, and therefore had a higher glucose content, were darker and more reddish.

Keywords: Amylase; Amyloglucosidase; Hydrolysis; Oligosaccharide; Wheat flour.