Research On Preparation By Enzymatic Hydrolysis And Physicochemical Characteristics Of Wheat Bran Oligosaccharide

China is a agricultural country with high output of wheat bran. But it is meanly used as fodder without further processing and high economic effectiveness. This paper researches on preparation by enzymatic hydrolysis and physicochemical characteristics of wheat bran oligosaccharide and provides technical parameters for the deep processing of wheat bran.The starch and protein in wheat bran were hydrolyzed by thermostable alpha amylase, glucoamylase and alkaline proteinase.The optimal conditions to remove the impurities were the amount of thermostable alpha amylase 105 U/g wheat bran,95℃, pH6.0, hydrolysis time 10 min.The amount of glucoamylase was 83 U/g wheat bran,60℃, pH 4.5, hydrolysis time 20 min. The amount of alkaline proteinase was 0.0192 AU/g wheat bran, 60℃, pH8.0, hydrolysis time 10 min.The orthogonal experiment method was used to make sure the process of preparing the oligosaccharide by enzyme. The optimal conditions of crushed wheat bran to prepare oligosaccharide were that the amount of cellulose and xylanase were 8 U/g wheat bran and 34 U/g wheat bran respectively,50℃, pH5.5, hydrolysis time 2 h. The optimal conditions of extruded wheat bran to prepare oligosaccharide were that the amount of cellulose and xylanase were 16 U/g wheat bran and 34U/g wheat bran respectively,50℃,pH5.5, hydrolysis time 2 h. The optimal conditions of ultrafine grinding-extruded wheat bran to prepare oligosaccharide were that the amount of cellulose and xylanase were 8 U/g wheat bran and 34 U/g wheat bran respectively,50℃, pH 5.5, hydrolysis time 1 h.The study on the oligosaccharide by GC, SEM, DSC and DLS shows that this three kind of oligosaccharide were composed by oligosaccharide, xylose, mannose, galactose and glucose. Their surfaces were anomalous under SEM. There were no significant differences of thermodynamic and physico-chemical property between three kinds of oligosaccharide. Extrusion and Superfine processing can reduce the size of oligosaccharide. Prepare with the oligosaccharide of the crushed wheat bran, the average size of oligosaccharide of the extruded and the ultrafine grinding-extruded wheat bran were decreased by 11.6% and 40.6%respectively, and the effective size were decreased by 1.5% and 28.1% respectively.The influence of oligosaccharides on starch cooking process was studied by RVA. The result showed that oligosaccharides reduced the viscosity of starch on the process of cooking.Texture analyzer confirmed the effect of oligosaccharide on the quality of noodles. The oligosaccharides had significant effect on the hardness and chewiness of the noodles. While it had no significant effect on the springiness and cohesiveness.