Effect Of Differential Pressure Explosion Puffing On Structure And Function Of Soybean Residue Fiber

With soybean residue as material, this paper discussed the differential pressure explosion puffing processing. The extraction process of soybean residue SDF was identified and optimized, the physicochemical property, structure and antioxidative activity were been studied.The process parameters of differential pressure explosion puffing processing was that 83%water content of raw materials, treatment temperature of 70℃, process-time of 90 min, and the soluble dietary fiber content of soybean residue raised from 3.9% to 18.2% after explosion. The increased SDF was mainly comprised by the degradation of cellulose and hemicellulose.The physical property experiments showed that the water-solubility, expansion and water holding capability of explosion puffing soybean residue were significantly improved. The explosion puffing soybean residue remained structural stability below 200℃ through the analysis of differential scanning calorimetry (DSC). The fiber structure of explosion puffing soybean residue appeared degradation observed using the scanning electron microscopy (SEM).With soybean residue SDF yield for index, the parameters of extraction process was material-water radio of 1:50, enzyme volume of 2‰, extraction time of 1 h, extraction temperature of 40℃. Under this condition, the puffing soybean residue SDF yield was 14.7%, the raw soybean residue SDF yield was 2.8%.The physicochemical characterization of ESDF was elucidated, and the result showed that the water content was 6.7%, water solubility was 19.2 g, the uronic acid content was 24.2%, and the intrinsic viscosity was 8.14 mL/g.The means of HPLC, IR and GC instrumental analysis were used to identified the SDF. The HPLC result showed that the content of molecular weight above 10000 Da part in RSDF was 96% as 75% in ESDF. The result of IR analysis showed that the characteristic of both RSDF and ESDF were typical infrared spectra of polysaccharide, and there were characteristic absorption peaks of functional groups of polysaccharide. The result of monosaccharide composition showed that the monosaccharide in both of RSDF and ESDF were mostly fucose, ribose, rhamnose, arabinose, xylose, glucose, mannose and galactose, but with different molar ratio.Through the ethanol fractional precipitation method two uniform components RSPP-1 and ESPP-2 were separated from the RSDF and ESDF.The result of vitro antioxidant model experiment including DPPH·, hydroxy free radical and ABTS+ free radicals showed that the soybean residue SDF had certain antioxidant activity. The ESDF antioxidant activity was slightly higher than RSDF, as the antioxidant activity of RSPP and ESPP were below both RSDF and ESDF.