Functional characterization of brown rice flour in an extruded noodle system

Abstract

Brown rice flour has been utilized as a health-functional ingredient for extruded gluten-free noodles. Thus, its functional qualities were evaluated. Brown rice flour had greater resistance to dough mixing, whereas the thermo-mechanical values were reduced during heating and cooling. During extrusion, the presence of more non-starch components in brown rice flour led to a lower degree of gelatinization that could be related to the lower cold initial viscosity and expansion ratio of noodles. The structural matrix of the noodles seemed to be weakened by brown rice flour, thereby reducing the breaking strength and tensile properties of the noodles and increasing their cooking loss. However, brown rice noodles exhibited significantly higher 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, ferric reducing powder, and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical-scavenging activity by 21-, 28-, and 21-fold, respectively, than white rice noodles. Thus, extruded noodles with enhanced antioxidant activities were successfully produced with brown rice flour, probably encouraging food industry to develop a variety of brown rice products with health benefits.