Enzymatic Hydrolysis,Antioxidant Activity And Application Of Polysaccharide From Auricularia Auricular

Auricularia auricular polysaccharide has biological activity,and its application value is of great significance to the development of Auricularia auricular industry.However,because of its poor water solubility,high molecular weight and high viscosity,natural Auricularia auricular polysaccharide is not conducive to cross the multiple cell membrane barriers to bioabsorption into the body to play its functional activities.Moreover,the direct injection of macromolecular substances into the body is highly toxic,which limits the scope of application of Auricularia auricular polysaccharide.In order to reduce the molecular weight and increase the application value of polysaccharide from Auricularia auricular,this paper used Auricularia auricular as raw material,polysaccharide was extracted from Auricularia auricular with hot water and alcohol-precipitation method,polysaccharide was enzymatically hydrolyzed by cellulase.The degradation conditions were optimized using a response surface methodology.The effect of degradation treatment on the antioxidant activity and structure of polysaccharide from Auricularia auricular was analyzed.Finally,compound beverage was prepared by compounding Auricularia auricularr and Lycium ruthenicum Murr.,and the antioxidant activity of composite beverage was studied.The specific investigations in this work can be shown as follows:1.Polysaccharide?AAP?was extracted from Auricularia auricular with hot water and alcohol-precipitation method.AAP was enzymatic hydrolyzed by cellulase?400U/mg?.The degradation conditions were optimized using a response surface methodology.The resulting optimal enzymolysis conditions were as follows:enzyme dosage,13500 U/g;enzymolysis temperature,50°C;and pH,4.2.Under these conditions,hydrolysis was carried out for 3 h and hydrolysate was named as C-EAAP,the actual yield of reducing sugar was 16.50 mg/mL and the DPPH radical scavenging rate was 87.97%.2.The in vitro antioxidant activities of AAP and C-EAAP were evaluated by determining their ferric iron reducing power,DPPH radical scavenging ability,hydroxy1radical scavenging ability?·OH?and superoxide anion radical scavenging ability?·O₂^-?.It was found that the antioxidant activity of C-EAAP was greatly increased when compared to those of AAP.At 5 mg/mL,the ferric iron reducing power of AAP and C-EAAP were 0.771?1.393.The IC₅₀ on DPPH scavenging ability by AAP,C-EAAP,was 3.300 mg/mL,1.580 mg/mL,respectively.The IC₅₀ of AAP,C-EAAP,on hydroxyl radical scavenging ability was 3.145 mg/mL,1.902 mg/mL,respectively.The IC₅₀ of AAP,C-EAAP,on superoxide anion radical scavenging ability was 4.092mg/mL,2.146 mg/mL,respectively.3.The structure of C-EAAP was observed by modern techniques such as GPC,HPLC,FT-IR and NMR.The results show that C-EAAP was mainly composed of mannose?57.1%?,glucuronic acid?10.0%?,rhamnose?0.4%?,glucose?22.5%?,galactose?2.9%?,xylose?6.0%?and fucose?1.1%?.AAP and C-EAAP contained alpha and beta glycoside configurations.The results showed that the degradation treatment had no effect on the main chain structure of the polysaccharide,and the essential beta-pyranose configuration of AAP did not change and made the molecular weight of the polysaccharide smaller.4.A new compound beverage was prepareed by the degraded Auricularia auricular polysaccharide and Lycium ruthenicum Murr.as raw materials with the addition of citric acid,honey,carboxymethyl cellulose sodium,pectin and xanthan gum.The sensory evaluation was used as the reference index,the raw material liquid formula was ensured by single factor and response surface methodology:Auricularia auricular juice 16%,Lycium ruthenicum Murr.juice 18%,citric acid 0.20%and honey 6%;The centrifugation sedimentation rate was used as the reference index,the single factor and response surface methodology were used to ensure the optimal compound ratio of the compound stabilizer in the beverage:carboxymethyl cellulose sodium 0.08%,pectin0.07%and xanthan gum 0.04%;DPPH,hydroxyl and superoxide anion radical scavenging rates of beverage were 59.20%?43.60%?67.45%,respectively.