Effect of extrusion modification on the physicochemical properties of brown rice flour

The effects of extrusion modification on the pasting properties, hydration properties, damaged starch content and the microstructure of brown rice flour were studied. The results showed that the peak viscosity, minimum viscosity and final viscosity of extrusion modified brown rice significantly increased with the increasing of material moisture, the water absorption and swelling power also significantly increased, and the water solubility and damaged starch dramatically reduced. The temperature was significantly negatively related with water absorption index and swelling power (p<0.05) . The screw speed was the same with the peak viscosity and minimum viscosity (p<0.05) . Extrusion modification significantly enhanced the hydration properties, and decreased the pasting properties of brown rice flour. Meanwhile, extrusion modification made the microstructure form the granular into the surface folds irregular flakes, which enhanced the water solubility.