Abstract:

In order to optimize the extrusion technology of rice bran, the effects of rice bran granule size, water content and extrusion temperature on the yield of soluble dietary fiber from rice bran were explored by response surface methodology on the basis of single factor experiments. The optimal extrusion conditions were determined to be: rice bran granular size, 0.175 mm; water content, 33%; and extrusion temperature 164 ℃. The yield of soluble dietary fiber from rice bran was 19.23% under these extrusion conditions, which was close to the theoretical value. The importance of the above three process conditions affecting the extraction rate of soluble dietary fiber from strong to weak was in an order of water content, extrusion temperature and rice bran size. The extruded rice bran exhibited a significant improvement in expansion power, water-holding capacity, water-binding capability and oil-absorbing capacity. Comprehensive material property value of extruded rice bran exhibited a 2.12-fold improvement. Therefore, the extrusion technology can greatly improve the content of soluble dietary fiber in rice bran and comprehensive material properties, which will provide theoretical references for the utilization of rice bran in food industry.

Key words: rice bran, extrusion, dietary fiber, response surface methodology