Study On The Ingredients Rich In Oligosaccharide Manufactured By Blasting Extrusion Cooperated With Enzymolysis From Wheat Bran

In this paper,wheat bran was used as materials to study the optimum process parameters of improving the soluble dietary fiber(SDF)content by blasting extrusion and the enzymolysis of cellulase.Here the molecular weight,monosaccharide composition,structure and in vitro functional properties of the wheat bran SDF were considered.And then the optimum parameters of β-mannanase hydrolysis in riching the oligosaccharides content of wheat bran SDF were determined.The oligosaccharides were also crude extracted and studied.The optimum parameters of blasting extrusion were:temperature 190℃,screw speed 125 r/min,diameter of mold hole 3 mm.In this condition,the wheat bran SDF content was 10.33%.The improvement of wheat bran SDF on water retention capacity,water solubolity and swelling capacity was largely due to the blasting extrusion.Observing from the X-ray diffraction spectrogram(XRD)and scanning electron microscope(SEM),the wheat bran’s fiber structure becomes porous granular after extrusion.And the differential scanning calorimetry(DSC)showed a good thermal stability of wheat bran whether treated or not.The optimum parameters of further improved the SDF content of extruded wheat bran with cellulase enzymatic method were:enzymatic temperature 50℃,enzymatic time 1.5 h,enzyme amount 1:50.In this condition,the SDF content of enzymolysis wheat bran was 14.62%.The extracted wheat bran SDF was canary yellow powder,soluble in water,insoluble in ethanol or other organic solvents.Its water solubility was 18.02 g/100g,total sugar content 60.66%,protein content 3.28%,uronic acid content 21.07%,with 3%reducing sugar and no starch.The high-pressure liquid chromatography(HPLC)results showed that the molecular weight of the main polysaccharides in SDF were 1.44×106Da and 3.17×104 Da,the two contents altogether occupied 88.91%.Seven types of monosaccharides(ribose,rhamnose,arabinose,xylose,mannose,glucose,galactose)in the SDF were identified by gas chromatography(GC),with the glucose at a higher level.The fourier infrared spectrometer(FT-IR)results showed that the blasting extrusion didn’t change the structure of the main functional group in SDF,however some vibration peaks had a little change.The optimum parameters of preparation of high oligosaccharides content SDF according to β-mannanase enzymatic method were:enzymatic temperature 55℃,enzymatic time 3.5 h,enzyme amount 1:5.After enzymatic hydrolysis,the mixture was subjected to ultrafiltration by hollow fiber ultrafiltration membrane.The filtrate was concentrated and lyophilized,the yield of crude oligosaccharide was 36%.HPLC results indicated the large proportion component in the rough oligosaccharide mixture was glucose with molecular weight of 1.35×103 Da,about 22.52%.The in vitro functional experiments pointed out that the rough oligosaccharide mixture had certain antioxidative activities.