Study Of Production Of Modified Soluble Soybean Polysaccharides And Its Characteristics

It could increase the additional value of bean dregs and avoid wasting resources byproducing soluble soybean polysaccharide with okara. However, the extracted SSPS have lowtransparency, emulsifying stability in the O/W emulsion, and precipitating stability in theacidic milk drink, which seriously affects its application in the food industry. This paper wasmainly to solve the low transparency, improve SSPS emulsifying stability in the O/Wemulsion, precipitating stability in the acidic milk drink and film-forming properties. It isconsidered that we can produce SSPS with different functional properties according todifferent purposes of SSPS.SSPS was prepared from okara firstly. Optimial process parameters were determined byresponse surface: ratio of material to water1:30, pH4.0, extraction time2.5h, and theextraction temperature118.12℃. Under this condition, polysaccharide yield was (37.88±0.12)%, which was very close compared to the theoretical value after test.The effects of modification conditions of removing methyl esterification on the DE valueand molecular weight of SSPS were studied; DE value and molecular weight of SSPS weretransformed from68.2%and467kDa to52.6%and402kDa respectively by controlling otherconditions in certain circumstance, and temperature from50℃to90℃change; whencontrolling other conditions in certain circumstance, pH from9to13, DE value and molecularweight were changed from83.2%and490kDa to51.5%and398kDa respectively;consequently, temperature and pH values of the two modified conditions had importantinfluence on DE value and molecular weight of SSPS. The impact of time was inferiorcompared to temperature and pH value; DE value and molecular weight of SSPS weredecreased from67.7%and466kDa to62.8%and453kDa by controlling other conditions incertain circumstance, time from1h to3h.The physicochemical and functional features of SSPS obtained under modification ofremoving methyl esterification were studied.1. Through the research of modified SSPSviscosity, rheological properties, and zeta-potential, SSPS with high DE value and molecularweight had bigger viscosity; when concentration of SSPS were5%and10%(w/w), all SSPSshowed newtonian fluid behavior; however, when the concentration of SSPS was20%, SSPSwith49%~66%DE values showed newtonian fluid behavior, and SSPS with74%~83%DEvalues showed nonnewtonian fluid behavior; and SSPS with low DE value had more negativecharge.2. Emulsifying stability of modified SSPS on O/W emulsion and precipitatingstabilization of SSPS on acidic milk drink were studied; SSPS with low DE values andmolecular weight had good emulsifying stability when it was added to O/W emulsion; whenSSPS was applied to acidic milk drink, centrifugation precipitating rate of acidic milk drinkwas smaller when DE value of SSPS was lower, which expressed good stabilization.3. Filmformed by SSPS with high DE value had smoother surface, compact structure, and barrierproperties compared wih that of SSPS with low DE value, which could prolong the storagetime of fruits and vegetables. Finally, the effect of enzymatic hydrolysis on transparency of SSPS was studied.Through precipitation analysis of SSPS by high-speed centrifugation and enzymaticexperiment of protein in SSPS, the protein was identified as a major factor to affect thetransparency SSPS. Alkaline protease treatment significantly improved the transparency ofSSPS, and the transparency was added from initial30%to70%. The optimial conditions ofalkaline protease enzyme were determined: enzyme amount2/1000of SSPS (w/w),hydrolysis time45min, concentration of substrate10%(w/w). Experiments were identifiedthat SSPS after alkaline protease treatment had similar emulsifying stability, precipitatingstability and film-forming features with SSPS without alkaline protease treatment.