Effects of twin-screw extrusion treatment of brown rice flour on the physicochemical properties of gluten-free biscuits

To address issues such as high water absorption, poor extensibility, and difficult shaping of dough during the processing of gluten-free biscuits, modified brown rice flour can be added. To clarify the impact of modified brown rice flour on the physicochemical properties of gluten-free biscuits, brown rice flour was treated under different twin-screw extrusion conditions (temperatures: 135, 145, 155 ℃; moisture contents: 17%, 20%, 23%). The swelling properties, hydration properties, solubility, pasting properties of brown rice flour, as well as the color, texture, and sensory evaluation of biscuits were measured. The brown rice flour was treated under different twin-screw extrusion conditions, and the best extrusion conditions were obtained by variance and correlation analysis, and the highest score of sensory evaluation of biscuits was obtained. The results showed that the swelling ratio of brown rice flour was the highest under the extrusion condition of 17% moisture cotent at 155 ℃, and the swelling potential was the highest under the extrusion condition of 20% moisture content at 135 ℃. There was no significant difference in brown rice flour under different extruding conditions. The maximum solubility was obtained at 145 ℃ and 17% moisture content. The viscosity of brown rice powder was the highest under 135 ℃ and 20% moisture content. When the puffing temperature of brown rice flour was between 135 ℃ and 155 ℃, the L^* value of biscuits first increased and then decreased, the a^* value first decreased and then increased. The hardness of the biscuits with modified brown rice flour increased by 19.9%-132.0%, with the highest hardness observed at 135 ℃ and 17% moisture content. Under the conditions of temperature 155 ℃ and 17% moisture content or 135 ℃ and 23% moisture content, the biscuits made from brown rice flour had the best taste, strong flavor, uniform particles, and no odor, achieving high sensory evaluation scores. Extrusion treatment improved the hydraulic properties and solubility of brown rice flour to a certain extent, reduced the retrogradation value, alleviated the aging of rice products, shortened the baking time, and enhanced their nutritional value.