Abstract: What this text introduced is by means of a new pretreatment technology--Extrusion, dealing with the raw materials of bean dregs, and improving the yield of Soluble Dietary Fiber (SDF). Through the single factor experiment and L9(34)orthogonal experiments, it can be gotten to the optimum processing conditions of bean dregs dietary fiber: the consumption of NaOH was 5% and trypsin was 0.3%, soaking time with alkali was 60 min, soaking temperature was 80℃. The content of Insoluble Dietary Fiber (IDF) in this product was 81.07%, the SDF was 6.94%. Because the physiological function of the SDF was approved and was paid more attention in recent years, the reports about it were more and more too. It was acknowledged that the Extrusion technology can improve content of Soluble in dietary fiber, because the most of the semi-cellulose and a few of the cellulose could be decomposed to the SDF with high temperature, high pressure, high shear strength and friction. Therefore, putting the Extrusion technology in the pretreatment course of producing Dietary Fiber (DF) with bean dregs can obviously improve the yield of the SDF. Through L9(33)orthogonal experiments, got the optimum processing conditions of single screw extrusion: 25% of supplies moisture, push temperature 180℃, rotational speed of screw 175r/min. Under these conditions, the yield of SDF was raised to 19.45% from 6.94%.

Key words: dietary fiber, soluble dietary fiber, bean dregs, pretreatment, extrusion