Abstract: On the basis of one-factor-at-a-time experiments, response surface methodology was employed for the optimization of process parameters for the twin-screw extrusion of rice bran. Soluble dietary fiber (SDF) content in extruded rice bran was investigated with respect to extrusion temperature, material moisture content and material granularity. The process parameters were ranked in decreasing order of their effect on SDF content in extruded rice bran as follows: extrusion temperature, material moisture content and material granularity. After extrusion at 170 ℃, the SDF content of 80 mesh (0.175 mm) rice bran with a moisture content of 35% was determined to be 20.85%, close to the model-predicted value.

Key words: twin-screw extrusion, rice bran, soluble dietary fiber (SDF)