Effect Of Extrusion Process On Soluble Dietary Fiber And Physical Properties Of Soybean Residue

Soybean residue is the by-product of soybean milk production process, it is rich in dietary fiber. Besides dietary fiber, soybean residue has high quality of protein. The ratio of essential amino acids to total amino acids in soybean residue was similar to soybean products. On the other hand, fat in soybean residue is as abundant as protein in that. So soybean residue was considered as source of good food additive. In this study, soybean residue was used as materials and treated with extrusion technology. The content of soluble dietary fiber (SDF) in soybean residue and its physical properties was observed as well as blood lipid-lowering function.In extrusion process, water content of raw materials, extrusion temperature and extruder speed was analyzed, while the objective was increment of SDF. The results of single factor experiment and orthogonol test suggested that, as the temperature was160℃, water content of raw materials was25%, revolution speed of extruder was100r/min, the soluble dietary fiber content of soybean residue raised from2.7%to30.1%after extrusion. The physical property experiments showed that the water-solubility, expansion and water hold-bility of extruded soybean residue raised10.4%,15.6%and130%, respectively. Extruded soybean residue remained structural stability below200℃through the analysis of differential scanning calorimetry(DSC). The fiber structure of extruded soybean residue appeared thermal degradation observed using the scanning electron microscopy(SEM).Extruded soybean residue was used as additive source in animal experiments, and effect on blood lipid-lowering was observed. Through the observation of4weeks animal experiments, it was found that the level of TG, TC, HDL-C, LDL-C and AI improved. This meaned extruded soybean residue had great function of blood lipid-lowering.