Study On Preparation And Antioxidant Activity Of Auricularia Auricula Polysaccharide

Auricularia auricula,also known as tree fungus.The main active components are polysaccharides,which have antioxidant and other physiological activities.Therefore,Auricularia auricularis has attracted more attention in food,medicine and other industries.However,the natural polysaccharide has many disadvantages,such as high molecular weight,poor water solubility and high viscosity of solution,which is not conducive to the function of polysaccharides in the organism,which limits the application of polysaccharides.In order to reduce the molecular weight and improve the utilization value of Auricularia auricularis polysaccharide,the paper studied the polysaccharides from Auricularia auricularis from four aspects:optimization of hot water extraction technology,optimization of TFA degradation process,structure analysis of Auricularia auricularis polysaccharide before and after degradation,and antioxidant property of Auricularia auricularis polysaccharide.The details are as follows:1.The extraction process of AAP in hot water was optimized by single factor test and response surface test.The optimum technological conditions are as follows:the ratio of liquid to material is 60 m L/g,extraction temperature is 100?,and the extraction time is 3.5 hours.The actual measured polysaccharide yield was 8.03%.2.The degradation conditions of T-DAAP were obtained by using trifluoroacetic acid to degrade the polysaccharide of Auricularia auricularis.The optimal degradation conditions were obtained by single factor and response surface test.The optimal degradation conditions were:the concentration of TFA was 0.8m,the degradation reaction time was 2.1 h,the reaction temperature was 78.2?,and the degradation polysaccharide was 2 mg/m L,the scavenging rate of DPPH free radical was 70.37%.Using HPGPC analysis,it was found that Trifluoroacetic acid effectively degraded Auricularia auricula polysaccharides,and the molecular weight of polysaccharides was changed from 148.2 k Da to 37.5 k Da.The structure changes of polysaccharides before and after degradation were analyzed by HPLC,FT-IR and NMR.The results show that AAP and T-DAAP are mainly composed of man,Glc,Glc A,Xyl and Gal,and both of them contain?and?glycosides.Except for molecular weight,the degradation did not change the main structure of polysaccharides,and the structure of polysaccharide did not change.3.The scavenging ability of DPPH free radicals,·OH and·O₂^-free radicals of polysaccharides was measured and the antioxidant activity of polysaccharides was evaluated in vitro.The results showed that the antioxidant activity of T-DAAP was significantly improved compared with AAP.When the mass concentration of polysaccharide was 10 mg/m L,the T-DAAP was similar to ascorbic acid,which was stronger than AAP,reaching 95.39%.The clearance rates of T-DAAP and AAP to·OH were 36.49%and 23.67%.The removal capacity of T-DAAP and AAP to·O₂^-was66.33%and 55.00%.