Extraction Of Soluble Soybean Polysaccharide From Soybean Residue And Its Application In Bread

The soybean residue were made in the process of soybean product, which major composition was cell wall polysaccharide and contained 30% soluble polysaccharide. In this paper, the soybean residue was used as study material and the soluble soybean polysaccharide (SSPS) was studied in the following respects: extraction technologies, elementary purification, physical and chemisty quality and its application in bread. The main experiment results were as follows:1. SSPS extraction technique(1) hot-water extraction method: The optimum parameters for hot-water extraction method were ratio of liquid to raw material 30, extraction time 5.5 h, extraction temperature 90℃, extraction time 1. Under this condition, the purity of SSPS was36.04% and its extration rate was7.24%.(2) composite enzyme extraction: The optimum conditions were as follows: Neutral protease and cellulase were selected to mix with 2:3, pH 5.5, temperature 55℃, enzyme dosage 0.3%, ratio of liquid to raw material 25 and extraction time 2.5 h. Under this condition, the purity of SSPS was 51.30% and its extration rate was 16.16%.(3) ultrasonic-associated extraction: On the base of hot-water extraction method, ultrasonic 25 min, then extracted 1.5 h at 90℃, the purity of SSPS was 31.75% and its extration rate was 18.17%.Combined polysaccharide purity with the extraction rate, composite enzyme extraction could achieve the best extraction effect in the three extraction methods.2. Primary purification of SSPSDe-coloration experiments of SSPS by exchange resins and absorption resins were studied. DA201C, X-5, D315 were selected to fullfill the further orthogonal experiment. The results showed the optimum technological parameters were D315 resin at 55℃with pH 4.5. The de-coloration rate was 89.82%, the polysaccharide holding rate was 85.86%. Protein was removed by pancreatin. The purified SSPS accorded with the trade standard of LS/T3301-2005.3. Application of SSPS in breadThe results of sensory evalution and TPA test showed the bread with 1.0-1.4% SSPS looked fine, had bigger volume, which stucture inside looked exquisite, and also had better springness and lower hardness. At the same time, adding SSPS could stale the bread slower. And the improved effect of SSPS on bread could reach that of shahao flour on bread, SSPS will become a competitive bread additive.