Preparation Of Pleurotus Eryngii Polypeptide Oral Liquid And Evaluation Of Its Antioxidant Activity

[Objective]To provide technical support for industrial production,Pleurotus eryngii protein was used as raw materials to prepare a new type of polypeptide oral liquid with compound enzymes.The antioxidant activities of polypeptide oral liquid were also investigated.[Methods](1)The alkaline protease and papain was used as single factors and the degree of hydrolysis was used as an indicator,the most suitable amount of the alkaline protease and papain was determined by single factor expriments and then polypeptide solutions were prepared by complex enzymolysis.The polypeptide solutions were purified by Sephadex G-25 and the amount of polypeptide was determined using Biuret methods.Meanwhile,the polypeptide molecular weight range was measured through the Time of Flight Mass Spectrometry(TFO).The polypeptide solutions were diluted to 2%and then the polypeptide oral liquid was prepared with auxiliary materials.(2)The independent factors were carboxymethyl cellulose sodium(CMC),carrageenan and guar gumand,the optimum amount of three stabilizers was determined by single factor expriments.Moreover,the optimal ratio of compound stabilizers was selected by three-factor and three-level orthogonal expriments and using the rate of deposition as indicator.The amount of white sugar,honey,citric acid and compound stabilizer were confirmed by single factor expriments.And then the auxiliary materials formulation of oral liquid were optimized through the response surface design using the sensory evaluation as an indicator.Meanwhile,the peptide composition of oral liquid was detected by Time of Flight Mass Spectrometry.(3)The antioxidant activities of oral liquid were evaluated through the research of scavenge OH-·,DPPH·,O2-·,H2O2·.[Results](1)The optimum process of preparing peptides through complex enzymatic hydrolysis was solvent ratio 1:25,pH 10.5,and the amount of alkaline protease 1%.The solutions was hydrolysised for 24 h at 45?.The pH was adjusted to 6.5 and then 1.1%papain was added.The time of enzyme hydrolysis was set as 24h at 50?.The hydrolysis degree was 56.01%.The molecular weight of the polypeptide was 726 Da-2418 Da.(2)The ratio of compound stabilizer was CMC:carrageenan:guar gum = 2:5:1.The optimal formulation of Pleurotus eryngii polypeptide oral liquid was Pleurotus eryngii polypeptide 2%,white sugar 3%,honey 2.5%,citric acid 0.07%and composite stabilizer 0.12%.(3)Pleurotus eryngii polypeptide oral liquid exhibited antioxidant activities,especially when the concentration of polypeptide was 2%,the the reducing power was 0.171 and the scavenging rates of OH-·and DPPH·,H2O2· and O2-· were 96.54%and 61.11%,77.84%and 6.36%,respectively.[Conclusion]A novel oral liquid of Pleurotus eryngii exhibited antioxidant activities was developed.