Extraction,Structure Characterization And Antioxidant Activity Of Polysaccharides From Herixium Erinaceus

Hericium erinaceus is a traditional Chinese medicine-food homologous fungus,which has good medicinal value and health care effects.Polysaccharide is one of the main active ingredients of Hericium erinaceus,which has biological activities such as reducing blood sugar,anti-oxidation and anti-cancer,and has attracted widespread attention from researchers.At present,there are many studies on the extraction,structure and biological activity of polysaccharides from Hericium erinaceus,and most of the methods for extracting polysaccharides from Hericium erinaceus are hot water extraction,ultrasound and enzymatic extraction,but the polysaccharides are exposed to high temperature for a long time Will cause the structure of the polysaccharide to be destroyed,which will affect its biological activity.In order to keep the structure of the polysaccharide from being destroyed and maintain its high biological activity.Therefore,in this thesis,the extraction process of polysaccharides from Hericium erinaceus was optimized by low-temperature extraction at 4?,and then the pure HEP of Hericium erinaceus polysaccharide was obtained,and its structural characteristics and antioxidant effects were studied.In this experiment,the dried Hericium erinaceus powder was used as raw material.The optimal extraction process of polysaccharides from Hericium erinaceus was determined by single factor and orthogonal experiment:extraction temperature was 4±0.5?,extraction time was 12 h,and ratio of material to liquid was 1:40(g/mL).The extraction rate under this process condition was 4.23±0.10%.The supernatant was removed by centrifugation at 4±0.5?,repeatedly frozen and thawed to a volume of 1/5,precipitated with 70%ethanol,deproteinized by Sevage method,pigment removed by AB-8,and water-soluble by vacuum freeze-drying.The polysaccharide of Hericium erinaceus was purified by bag dialysis with a molecular weight of 3500 Da and Sephadex-G150 to obtain the polysaccharide of Hericium erinaceus,named HEP.The HEP sugar content was 92.43±0.23%and the uronic acid content was 3.16±003%by phenol-sulfuric acid method.The high molecular weight liquid chromatography analysis showed that the molecular weight of HEP was 1.97×104Da.The monosaccharide composition of HEP obtained by gas phase and ion exchange chromatography was fucose,galactose,glucose,mannose and a small amount of glucuronic acid in a molar ratio of 1:2.87:0.09:0.12:0.01.Through periodate oxidation,Smith degradation,methylation analysis,Fourier infrared and nuclear magnetic resonance analysis,it is estimated that HEP is based on ?-1-4-Fucose and a-1-6-Gal,The group consists of?3,6)-?-D-Man-(1?and?1,6)-gGlc,and ?-D-GlcpA-(1 is the T terminus.HEP was+55°.The connection mode of the glycosidic bond is.Congo Red and circular dichroism showed that HEP had no triple helix structure,and SEM results showed that the polysaccharide of Hericium erinaceus was a smooth layered structure.In vitro antioxidant experiments showed that HEP has a certain ability to scavenge DPPH free radicals,OH free radicals,O2-free radicals and ABTS free radical scavenging.However,HEP has strong DPPH free radical scavenging ability and the highest scavenging rate.It reaches 91.72±0.17%,which is basically equivalent to the removal ability of VC.