Study On Production Technology Of Soluble Soybean Polysaccharides

Soluble soybean polysaccharides (SSPS), as a new kind of functional food ingredient, not only can be used as a dietary fiber supplement, but also has excellent film-forming property, caking resistance, stability in dairy acid beverage, emulsifying property, foam stability and so on, which are widely used in food industry. There are rich dietary fiber and comprehensive nutrients in soybean residue, which is a good raw material, so we can obtain SSPS by using appropriate production technology. Although there are many difference studies on the extraction technology of SSPS from soybean residue, SSPS has not realized large-scale industrialized production in our country, because of the low yield and complex operation process. We studied the extraction technology, de-esterification technology, amplifying process of SSPS and analysised the physical and chemical properties characteristics of SSPS. The main results were shown as follows:1. Taking okara as raw material, SSPS can be obtained through high temperature treatment and acid extraction. Analysis single factor test and L9 (33) orthogonal experiment, the optimal extraction condition of achieving superior stability of SSPS was at pH 3.5 and 125℃ for 90 min. Under the optimum process, the polysaccharides and protein content of SSPS were 66.05% and 3.69%, the sediment ratio decreased to 0.72%, while the sediment ratio of CK was 1.45%. The extraction pH was the major influencing factor, followed by extraction temperature and extraction time.2. Taking degree of esterification (DE) as index, extract of SSPS was de-esterificated by pectinesterase. On the basis of single factor experiment, L9 (34) orthogonal experiment sifted the best de-esterification conditions to obtain lower DE was when the enzyme activity was 1.5U/mL, optimum enzymetic pH5 and 50℃ for 50min. According to the conditions, DE was 21.86%, but the DE of SSPS was 71.78%, which were not de-esterificated.3. When the acid extraction process and de-esterification technology conditions of SSPS were amplified at the level of 50L, the optimum extraction conditions was heating at 125℃ for 90min in pH3.5, corresponding to optimal conditions in the laboratory; The best de-esterification conditions to treated the extract of SSPS was when the enzyme activity was 1.5U/mL, optimum enzymetic pH5 and 50℃ for 50min, or when the enzyme activity was 1.5U/mL, optimum enzymetic pH5.5 and 50℃ for 40min. Considering energy consumption and efficiency of production in the factory, however, the latter is advanced. According to the final production technology, the yield of SSPS was 27.75%, the polysaccharides and protein content of SSPS were 63% and 3.7%, the DE of SSPS was 23.22%, and the sediment ratio decreased to 0.52%.4. Analysis the physical and chemical properties of SSPS obtained in the amplification process. The results indicated SSPS met the the national grain and oils standard, the protein content of SSPS was 3.69%, and the whiteness reached up to 81.4% without bleaching process, which were significantly higher than Japanese and domestic polysaccharides (74.5% and 53.4% respectively). However, the transparency of the polysaccharides was only 43.1%, and less than Japanese polysaccharides (57.8%) and domestic polysaccharides (55.6%); the dietary fiber content of Japanese polysaccharides was up to 70.11%, while the homemade polysaccharides’ dietary fiber content was only 65.05%. The sediment ratio of SSPS made in our laboratoy was up to 0.55% in 20d, higher than Japanese polysaccharides (0.53%).