Effect of Different Extrusion Treatments and Particle Size Distribution on the Physicochemical Properties of Rice Flour

Rice flour is an interesting alternative for developing gluten free products, but its features do not always meet the process requirements. The objective of this study was to modify the functional properties of rice flour by combining extrusion and size fractionation. Different extrusion conditions (barrel temperature, feed moisture content and feed rate) were applied to vary the severity of the treatment on the flour constituents. Extrusion and mechanical fractionation of the rice flours modified their behavior affecting hydration, thermal and pasting features, besides their susceptibility to enzymatic hydrolysis. Specifically, onset and peak temperature increased and gelatinization enthalpy decreased when increasing barrel temperature of the extrusion. Fine flours with stronger extrusion (high temperature barrel) showed the highest susceptibility to enzymatic hydrolysis. Overall, the combination of both physical treatments maybe an attractive alternative for obtaining clean label rice flours with modified features.