Preparation And Properties Research Of Soluble Dietary Fiber In Wheat Bran

With the increasing refinement of the people’s diet, the dietary fiber is to bevalued. As China has a huge production of wheat bran, it is also an excellent source ofdietary fiber. In this study, bran dietary fiber was dealed with a twin screw extruderfor extrusion processing, aimed at improving its soluble dietary fiber content, andpreliminary study of the properties of the soluble dietary fiber.Using the washing method to remove the starch in the bran. After washingprocess, bran starch content was decreasd from30.90%to5.7%. Single factor andorthogonal experiments of separation of the bran protein by alkaline protease showedthat the optimal conditions for alkaline protease to remove the bran protein wasalkaline protease dosage1.2%; hydrolysis temperature65℃; hydrolysis time1.5h;enzymatic pH7.5, the protein content was decreasd from14.76to4.25%.The preparation of wheat bran was dealed with extrusion progress usingtwin-screw extruder, and selecting three factors-the material moisture content, screwspeed and extrusion temperature for the single factor and orthogonal experiments, theoptimum extrusion conditions was obtained, i.e. the moisture content of wheat bran1.2%, host outlet temperature170℃, the host speed225r/min. After extrusion,soluble dietary fiber content increased from3.22%to10.14%comparing to rawmaterial. Structure and properties of extruded wheat bran were studied and found thatextrusion processing changed the surface structure of wheat bran and improved itsporosity and led to the rise of its water solubility, water holding capacity andexpansion force, water holding capacity increased2.52%and the expansion force was60.0%.Soluble dietary fiber was extracted from extruded wheat bran by waterextraction-alcohol precipitation method, solubility experiments showed that thedissolution rate of soluble dietary fiber in bran was up to100%when the temperaturereaches above70℃. Cation adsorption experiments showed that soluble dietary fiberin bran had a strong cation adsorption capacity. The monosaccharide composition ofsoluble dietary fiber in bran was determined by GC-MS, the result showed that itbelonged to polydextrose. Immune activity tests showed that different concentrationsof SDF could significantly promote the proliferation of splenic T and B cell, and the SDF concentration and proliferative had a dose-dependent effect. experiments thatsimulated bile salts in vitro assay showed that the SDF could significantly absorbsodium cholate in solution, the adsorption amount up to0.34g/L after absorbing2h.Free radical scavenging experiments displayed that the OH and DPPHradical-scavening scavenging activity of SDF was51.0%and16.1%respectively.