Antioxidant Activity Of Polysaccharides From Scleroium Rolfsii Fermented Corn Starch And Corn Soak

Scleroium rolfsii exopolysaccharides(SEPS)is extracellular ?-glucan.SEPS can be used in many fields such as food and medicine based on its water holding capacity and stability.However,nowadays most studies on Scleroium rolfsii exopolysaccharides pay attention to its physicochemical properties and never seen a research on its physiological activities.This research group screened one Scleroium rolfsii strain which can use corn starch and corn soak as carbon and nitrogen source for its fermentation,besides,the polysaccharide production reached 26.226g/L.But few studies on its physiological activities is not conducive to the promotion and application of SEPS.Therefore,in this paper,the best deproteinization and decolorization methods were selected,then antioxidant activities of SEPS in vitro and its stability were analyzed,the antioxidant activities of SEPS in vivo were measured at last.These provided a theoretical basis for the application of polysaccharide in functional foods.The main findings are as follows:1.Using DPPH and ABTS free radical scavenging rate as evaluation indexes,the free radical scavenging ability of crude polysaccharide,polysaccharide deproteinized by Sevag method and polysaccharide deproteinized by isoelectric precipitation method were compared,the isoelectric precipitation method was selected as the deproteinization process of SEPS.2.Using DPPH and ABTS free radical scavenging rate as evaluation indexes,the free radical scavenging ability of polysaccharides decolored by ethanol sedimentation,macroporous resin and hydrogen peroxide were compared,the ethanol sedimentation method was selected as the deproteinization process of SEPS.3.High performance liquid chromatography(HPLC)was used to measure the monosaccharide composition and mole ratio of SEPS,the result was Xyl: Man: Glu: Glu A: Gal: Gal A: Tal: Ino = 5.8: 5.3: 28.5: 2.2: 5.6: 17.3: 24.3: 7.1.The FTIR spectrums of SEPS suggested that SEPS was glucan linked by ?-glycosidic bond.4.SEPS has antioxidant activity in vitro.The results showed that when the concentration of SEPS was 5 mg/mL,the free radical scavenging rate of ABTS,superoxide anion free radical and nitroso-group were 89.39%,61.21% and 52.3%,respectively.The inhibition rate of linoleic acid peroxide was 24.81%.5.There was no significant effect on the free radical scavenging ability of SEPS by irradiance and ultrasonic treatment.The maximum value of DPPH and ABTS free radical scavenging rates reached 84.92% and 86.73% when the temperature was 50?.The maximum value of DPPH and ABTS free radical scavenging rates reached 82.87% and 86.51% when the pH was 8.0.6.Mice gavaged with SEPS showed higher enzyme activity of SOD,CAT,GSH-Px and lower content of MDA,which indicated that SEPS has antioxidant activity in vivo.