Research On Preparation And Modification Of Soluble Dietary Fiber From Wheat Bran

The amount of dietary fiber in wheat bran can be around 60%.Wheat bran dietary fiber has a sufficient source and beneficial human body functional properties,as the basis for processing raw materials there is great potential in the food processing and related fields also has broad prospects.But because some functional properties are less effective,wheat bran dietary fiber can not meet the needs of food and processing development and application,and wheat bran dietary fiber in the field of deep processing and application of food is limited.In order to improve the development and utilization of wheat bran soluble dietary fiber resources,this experiment adopts the xylanase and cellulase and xylanase and cellulase compound enzyme three methods were use to modify the glucose adsorption capacity of wheat bran soluble dietary fiber,and research the effect of enzymatic modification on its functional properties and structural properties.The results are as follows:wheat bran was defatted by hexane,removal of starch and protein by enzymatic hydrolysis ofα-amylase and alkaline protease for extraction of wheat bran dietary fiber.The extraction rate of wheat bran dietary fiber was taken as the index,and the optimum extraction conditions were determined by single factor test:a-amylase addition 3%,pH 6,70℃ hydrolysis 3 h;alkaline protease addition 3%,pH 11,50℃ hydrolysis 3h,Under the condition of the purity of wheat bran dietary fiber was 58.45%.With xylanase enzyme modified wheat bran dietary fiber,the optimal conditions for:enzyme addition 0.60%,pH 5.0,50℃ hydrolysis 3.0 h.Under the condition,the glucose adsorption capacity of X-SDF actual value was for 9.78mmol/g,the relative error was 0.72%.With cellulase enzyme modified wheat bran dietary fiber,the optimal conditions for:enzyme addition 0.32%,pH 4.5,50℃ hydrolysis 4.9 h.Under the condition,the glucose adsorption capacity of C-SDF actual value was for 9.70mmol/g,the relative error was 0.31%.Using xylanase and cellulase compound enzyme modification,the optimal conditions of wheat bran SDF for:the ratio of enzyme addition was 1:1.7,pH 4.75,51℃ hydrolysis 4.1 h.Under the condition,the glucose adsorption capacity of D-SDF actual value was for 9.85mmol/g,the relative error was 0.51%.The water holding capacity of X-SDF,C-SDF and D-SDF obtained by enzymolysis was 4.74g/g,4.82g/g,5.13g/g,compared with the unmodified SDF can improve the 17.9%,19.9%,27.6%respectively;holding oil force were 1.04g/g,1.07g/g,1.12g/g,compared with the unmodified SDF can improve the 25.3%,28.9%,34.9%;Enzymic modification after the expansion of the dietary fiber strength reduced.Analysis of SDF found in wheat bran before and after enzymatic hydrolysis,the SDF glucose adsorption capacity obtained by enzymatic modification was significantly higher than that of unmodified SDF,the adsorption capacity of D-SDF was the highest;SDF yield were significantly increased,D-SDF yield the-highest.Analysis of the physical and chemical properties of SDF before and after enzymic modification found:electron microscopy showed that X-SDF surface appear a few pieces of cracking and appear larger hole,C-SDF surface structure loose,the formation of more holes,D-SDF appear a large number of pieces of cracking,surface structure is loose,and appear dense holes,which significantly increase the specific surface area;Infrared spectrum showed that D-SDF appear O-H,C-H,C-O polysaccharide characteristic absorption peak,and phenolic compounds benzene ring characteristic absorption peak.