Optimization Of Liquid Fermentation Conditions Of Morchella Nigrostria And Study On Antioxidant Properties Of Its Polysaccharide

Morchella esculenta is a rare wild edible and medicinal fungi,nutritious,rich in protein,amino acids,polysaccharides,vitamins,minerals and fatty acids,flavor is delicious,loved by people.Studies have shown that Morchella esculenta have the effect of lipid-lowering,immune regulation,anti-oxidation,anti-fatigue,anti-radiation,anti-tumor and so on,has an important development and use value.Since Morchella esculenta cultivation technology is not mature,limited wildlife resources,brought problems to the development and utilization of Morchella esculenta products,however,study has proved the nutrient of mycelium liquid cultured and fruiting body was similar,so the submerged fermentation of Morchella esculenta has become a hot research.Conditions of this thesis on Morchella esculenta Peck liquid fermentation and hot water extraction of amino acids in the mycelium have been optimized,and the antioxidant properties of mycelium polysaccharides were studied,and strive for the Morchella esculenta Peck products development to provide a reference.The main research contents and results are as follows:1.The Morchella esculenta Peck liquid fermentation conditions optimizationBy orthogonal design to the Morchella esculenta Peck liquid fermentation temperature(A),fermentation time(B)and rotation speed(C)optimization,the primary and secondary order of three factors impact on the mycelium growth was fermentation temperature>fermentation time>rotation speed,the best combination of A1B2C3;the primary and secondary order three factors affecting the yield of mycelium polysaccharide was fermentation time>fermentation temperature>rotation speed,the best combination of A1B2C3;primary and secondary in the sequence of the three factors impact on the amino acids content in the mycelium:fermentation temperature>fermentation time>rotation speed,the best combination is A2B1C1.Finally through the intuitive analysis of the orthogonal experiment results the Morchella esculenta Peck best liquid fermentation conditions are fermentation temperature 27℃,fermentation time 8 d.rotation speed 180 r/min,the mycelium dry weight is 6.77g/L,amino acid content of mycelium is 918.12g/(100g),mycelium polysaccharide production is 1285.68mg/L.2.Hot water extraction amino acids in the mycelium conditions optimization and amino acid composition and content analysisOrthogonal design of the amino acids in the mycelium extraction conditions(extraction time,extraction temperature,solid-liquid ratio)to optimize,the primary and secondary sequence of the three factors affecting the amino acid extraction rate was extraction time>extraction temperature>solid-liquid ratio,the optimum extraction conditions were:solid-liquid ratio(g:mL)for 1:60,extraction time for 3h,extraction temperature for 75 ℃,amino acids extraction rate under these conditions was 1.4%.Morchella esculenta Peck mycelium have 17 kinds of amino acids,total amino acids 17.2g/100g,which contains seven kinds of essential amino acids(tryptophan was hydrolyzed in the process of sample processing and not detected),the amount of essential amino acids was 2.9g/100g,accounting for 16.8%of total amino acids.17 kinds of amino acids,arginine most,accounting for 57.3%of total amino acids,lysine and histidine followed,accounting for 12.1%and 10.8%respectively of the total amino acids.3.Added different hormones to the fermentation medium influence on the Morchella esculenta Peck mycelial growth and polysaccharide productionLiquid fermentation medium supplemented with different exogenous plant hormones and mycelium polysaccharide production has a different-effect on the dry weight of the Morchella esculenta Peck mycelium.For Morchella esculenta Peck mycelium dry weight and polysaccharide production,liquid fermentation medium supplemented with IAA best,IAA concentration 1.0μg/mL,the maximum dry weight of mycelium,up to 8.18g/L,compared with no added IAA increased 17.36%,IAA concentration was 2.0μg/mL,mycelium polysaccharide largest output,up 1851.30 mg/L,compared to no added IAA increased by 51.62%.4.The fermentation medium by adding different metal ions on the pulse of Morchella esculenta Peck mycelium growth,polysaccharide production and antioxidant propertiesAdding different concentrations FeSO4·7H2O,CuSO4·5H2O,ZnSO4·7H2O in the fermentation medium,Morchella esculenta Peck mycelium,mycelium polysaccharide production and polysaccharide antioxidant properties had some influence.For dry weight of mycelium and mycelium polysaccharide yield,the effect of adding ZnSO4·7H2O in liquid fermentation medium is best,the best dosage 400μg/L;mycelium polysaccharides on superoxide anion scavenging,select add 400μg/L of FeSO4·7H2O best,mycelium polysaccharide hydroxyl radical scavenging capacity,select add 300μg/L of CuSO4·5H2O best;mycelium polysaccharides on DPPH scavenging,select add 400μg/L of CuSO4·5H2O best.