Study On The Structure Analysis And Antioxidant Activity Of Water-soluble Polysaccharide From Soybean Dregs

As a natural biologically active substance,water-soluble soybean dregs polysaccharide has anti-tumor,anti-oxidation and antibacterial effects,and has a broad market and application prospects in the food industry of China.However,the current researches on the structure of water-soluble soybean dregs polysaccharides has not been in-depth,which limits the development of related functional foods.Therefore,soybean dregs was used as raw materials,used enzymatic-assisted hot water boiling extraction method to extract water-soluble soybean dregs polysaccharides,and carries out separation,purification,structure analysis and in vitro antioxidant activity studies on water-soluble soybean dregs polysaccharides.The research results will provide a theoretical basis for the subsequent product development and utilization of soybean dregs,and provide some solutions to problems such as environmental pollution caused by waste soybean dregs.The specific results are as follows:The water-soluble soybean dregs polysaccharide SSPS was extracted by enzyme-assisted hot water boiling extraction method,and the SSPS was fractionated by DEAE-cellulose ion exchange chromatography to obtain the neutral sugar fraction SSPS-N and the acid sugar fraction SSPS-A.It was analyzed by chemical composition,monosaccharide composition,infrared spectroscopy and scanning electron microscopy.The results show that SSPS,SSPS-N and SSPS-A have certain differences in chemical composition and monosaccharide composition;the three polysaccharides all contain the characteristic absorption peaks of polysaccharides;SSPS and SSPS-A both have the surface layer of spherical particles.Dense structure,while SSPS-N shows a flaky structure.SSPS-N was separated and purified by Sephadex G-100 gelcolumn to obtain three fractions of SSPS-N-a(23.0%),SSPS-N-b(65.5%)and SSPS-N-c(11.5%),and further its main components.The structure analysis of SSPS-N-b showed that the molecular weight of SSPS-N-b is 8.6 KDa,which is a homogeneous polysaccharide fraction,mainly containing galactose(Gal),glucose(Glc)and mannose(Man);infrared spectroscopy results show that SSPS-Nb has the general characteristic absorption peaks of polysaccharides;analysis of methylation,enzymatic hydrolysis and NMR results show that SSPS-N-b is mainly composed of ?-1,4-glucomannan and ?-1,4-galactan.And ?-1,4-galactan and ?-1,4-glucomannan exist in the form of non-covalent bonds.It is speculated that SSPS-N-b is ?-1,4-galactan and ?-1,A mixture of polysaccharides composed of 4-glucomannan.Ion exchange column chromatography was used to separate and purify SSPS-A,and two fractions,SSPS-A1 and SSPS-A2,were obtained.Among them,the yield of SSPS-A1 was45.5%.Sepharose CL-6B gel column was used to separate and purify SSPS-A1,and four fractions SSPS-A1-a(8.0%),SSPS-A1-b(9.0%),and SSPS-A1-c(20.8%)were obtained,SSPS-A1-d(8.8%);structural analysis of its main component SSPS-A1-c shows that the molecular weight of SSPS-A1-c is 31.6 KDa,which is a relatively uniform polysaccharide fraction,mainly containing half Lacturonic acid(Gal A),galactose(Gal)and arabinose(Ara);infrared spectroscopy results show that SSPS-A1-c has the characteristic absorption peaks of acidic polysaccharides such as OH,CH and C=O.At the same time,SSPS-A1-c There is also a certain degree of methyl esterification or acetylation modification;NMR results show that SPSS-A1-c is mainly composed of ?-1,5-Araf ??-1,4-Galp A and ?-Galp,and it is speculated that SSPS-A1-c is composed of Arabian galactose It is composed of glycan(AG)pectin and polygalacturonic acid(HG)pectin domains.The in vitro antioxidant activity of SSPS,SSPS-N and SSPS-A was studied.The research results show that SSPS has certain antioxidant activity;the antioxidant activity analysis of SSPS-N and SSPS-A shows that the antioxidant activity of SSPS-N is stronger than SSPS-A;taking DPPH free radical scavenging ability as an indicator,The antioxidant activity of different fractions of SSPS-N was investigated,and the results showed that SSPS-N-b has the strongest scavenging ability on DPPH free radicals.The different domains of SSPS-N-b were prepared by enzymatic hydrolysis and the antioxidant activity was studied.It is clear that SSPS-N-b The main domain of that plays an anti-oxidant effect is ?-1,4-galactan.