Optimization of Snailase Modification of Flammulina velutipes Insoluble Dietary Fiber and Its Effects on Physicochemical Properties
In order to increase soluble dietary fiber(SDF)content in Flammulina velutipes,its insoluble dietary fiber(IDF)was modified by snailase.Using SDF yield as the index,the technological parameters of snailase modification were optimized by single factor and orthogonal experiments.The modified dietary fiber samples with different SDF contents were determined for physicochemical properties and analyzed for structure.The results showed that the optimal conditions for IDF sanilase modification were using 2％snailase to hydrolyze under 35 ℃ and pH7.0 for 14 h,and the resultant SDF yield was 14.38％.Compared with unmodified IDF,the SDF content of the modified IDF derived under the optimal conditions increased by 363.87％.There were significant increases of water holding capacity,oil holding capacity,swelling capacity,cation exchange capacity,glucose adsorption capacity,glucose dialysis retardation index,cholesterol adsorption capacity and DPPH free radical scavenging capacity in the snailase modified IDF in a SDF content dependant manner.The Fourier transform near-infrared spectroscopy(FNIR)results showed that there were characteristic peaks 3 400 cm-1,1 739 cm-1 and 1 000-1 300 cm-1 in the IDF samples regardless of modification.However,the transmission of the modified IDF was significantly lower than that of the unmodified IDF.Scanning electron microscopy and particle size distribution analysis showed that the snailase modified IDF had a overall loose structure with a large number of lamella and a small amount of honeycomb structure,and its specific surface area was increased compared with the unmodified IDF.These structural changes were more obvious as the SDF content increased.X-ray diffraction analysis showed that the crystal configuration of F.velutipes IDF remained the same after snailase modification,with a slight decrease in diffraction intensity.These results suggested that snailase partially hydrolyzed glucan and hemicellulose in the insoluble dietary fiber of F.velutipes,thus increasing the content of soluble components and improving the physicochemical properties of F.velutipes dietary fiber.
万方数据
维普
