Study On Extraction,purification,structure Identification And Biological Activity Of Millet Polysaccharide

Millet originated in the Yellow River Basin,is one of the main food crops in China.Millet is rich in protein,fat,yellow pigment,polysaccharide and other active substances.In this paper,the extraction,separation,purification,structure identification and biological activity of Polysaccharides from millet were studied(1)The optimal extraction conditions of millet polysaccharide by ultrasonic assisted enzymatic method were as follows: the ratio of liquid to material was 1:22(g/m L),ultrasonic time was 21 min,cellulase dosage was1%,ultrasonic temperature was 60?,and the extraction amount of millet polysaccharide was 30.34 mg/g.(2)Different methods were used to deproteinize and decolorize millet polysaccharide.The deproteinization rate of papain sevag method was78.23%,and the retention rate of polysaccharide was 89.42%.The decolorization rate of D315 resin method was 88.00%,and the retention rate of polysaccharide was 80.20%.Two components MP-1 and MP-2 were obtained by DEAE-cellulose column chromatography,and MP-1 was further purified by Sephadex G-100 gel column chromatography.(3)The structure of MP-1 was analyzed: infrared spectrum showed that MP-1 was a pyranose;scanning electron microscope showed that MP-1was a sheet structure;HPLC showed that MP-1 was composed of rhamnose,glucose,galactose,xylose and arabinose,and its molar ratio was24.63:4.19:1:4.679:8.21;Congo red test showed that MP-1 had double helix In vitro antioxidant test showed that MP-1 had the highest scavenging rates of DPPH free radical,hydroxyl free radical and superoxide anion,which were 75.33%,70.69% and 68.62% respectively.(4)Millet polysaccharide can significantly improve the blood glucose level of high glucose and high fat diet combined with STZ induced hyperglycemia mice.Different doses of millet polysaccharide can alleviate the "three more and less" symptoms of hyperglycemia mice in varying degrees.After intragastric administration for 28 days,millet polysaccharide group could effectively reduce the blood glucose level of hyperglycemic mice and improve the glucose tolerance.The levels of serum triglyceride(TC),total cholesterol(TG)and low density lipoprotein(LDL-C)were significantly decreased(P < 0.05 or P < 0.01),and the levels of high density lipoprotein(HDL-C)were increased in all groups,which indicated that millet polysaccharide could effectively regulate blood lipid in diabetic mice;Compared with the model group,glutathione peroxidase(GSH-PX),superoxide dismutase(SOD),catalase(CAT)and malondialdehyde(MDA)in the high-dose group were significantly increased(P < 0.01),significantly increased(P < 0.05),and significantly decreased(P < 0.01),indicating that millet polysaccharide can effectively improve the antioxidant capacity of diabetic mice.