Study On Extraction Technology And Antioxidant Activity Of Polysaccharide From The Volva Of Dictyophora Rubrovolvata In Vitro

Dictyophora rubrovolvata is one of the"twelve characteristic industries"in Guizhou.Its funguses are often discarded as waste by producers,but the funguses contain active polysaccharides with high nutritional value and have pharmacological effects such as anti-oxidation and anti-fatigue.In this paper,polysaccharides were prepared from the volva of Dictyophora.This paper mainly carried out two parts of research:one was the study on the technology of polysaccharides from the volva of Dictyophora rubrovolvata,the other was the structural characterization and activity test of polysaccharides from the volva of Dictyophora rubrovolvata.Specific studies are as follows:1.Study on the technology of polysaccharide from the volva of Dictyophora rubrovolvatai)On the basis of the pilot process,design the pilot process and investigate its stability.The design route of pilot test process is as follows:feeding→reflow extraction in multi-function extraction tank→pipeline extraction（200 mesh）→single-effect concentration→scraper concentration→multi-function alcohol sinking in tank→vacuum pulse drying→cooling water circulation grinding→polysaccharide powder.The relative standard deviation（RSD）of the pilot process stability test was 1.92%,indicating that the pilot process has good reproducibility and strong stability.ii)On the basis of the pilot process stability test,single factor combined with orthogonal test method was used to optimize the pilot extraction process conditions.The optimized extraction conditions were as follows:solid-liquid ratio of 1:35 kg/L,extraction time of 2.5 h,extraction temperature of 85℃,extraction times of 2 times,the yield of polysaccharide was 18.85%.iii)Single factor combined with orthogonal test was used to optimize the concentration and alcohol precipitation process conditions.The optimum conditions for the concentration and ethanol precipitation of polysaccharides were as follows:concentration ratio 1:2 g/m L,ethanol precipitation time 2 h,ethanol concentration85%,ethanol volume multiple 4 times.2.Structural characterization and in vitro antioxidant activity of Polysaccharide from volva of Dictyophora rubrovolvatai)The structure of the polysaccharide from the volva of Dictyophora rubrovolvata prepared by pilot process was characterized by ultravlolet and infrared spectroscopy,nuclear magnetic resonance and high performance liquid chromatography.The results showed that the polysaccharides were pyran ring polysaccharides withα-andβ-configurations and molecular weight of 3.89~5×10~4 Da.The monosaccharides were mainly mannose,glucose and galactose.ii)The antioxidant activity of the polysaccharides prepared in pilot study was evaluated by determining total reducing power,DPPH free radical scavenging capacity and hydroxyl free radical scavenging capacity.Results:When the concentration was 6.0 mg/m L,the total reducing power of polysaccharides reached50%of ascorbic acid（Vc）.The DPPH free radical scavenging rate was 80.22%at 2.0mg/m L.When the concentration was 5.0 mg/m L,the hydroxyl radical scavenging rate was 72.13%.The EC₅₀ of DPPH free radical and hydroxyl free radical were 0.65mg/m L and 2.28 mg/m L,respectively,indicating that the pilot-scale polysaccharides had good activity.In conclusion,a stable and feasible pilot process was designed in this paper,and the optimal extraction process,concentration and alcohol precipitation processes were established.The polysaccharides with obvious antioxidant activity were obtained and their structures were characterized.The results of this study made it possible to transform the waste into treasure and enhance the added value of the volva of Dictyophora rubrovolvata.Meanwhile,it also provided data reference for the laboratory test of polysaccharide extraction to industrial production.