Preliminary Study On Liquid Fermentation Culture And Antioxidant Activity Of Pleurotus Geesteranus

Pleurotus geesteranus is a new species of edible fungi which is become more and more popular in recent years.It is delicious and rich of nutrient so that it deeply affected by people favorite.The previous studies have proven that it has 8 kinds of essential amino-acid,polysaccharide and many of the biological activities of Pleurotus geesteranus fruit body.In order to explore the mycelial biological activities of Pleurotus geesteranus,we firstly find the better method to preserve its mycelial for a long time,and then optimize the medium component and culture condition during the liquid-fermentation.We also study on the functional ingredients and antioxidant activities of fermentation solution.Based on the previous studies,we develop the Pleurotus geesteranus fermentation beverage so that it can provide more theoretical basis for the industrialize production of health related products.Agar-slant low temperature,nature culture media pole shape low temperature and liquid olefin normal temperature were studied respectively.During the 240 days,it was testified that nature culture media of broadleaf mixed sawdust was the best method for culture collection.The experiment discussed the method of liquid fermentation to obtain mycelium of Pleurotus geesteranus.By method of single factor and orthogonal designs the liquid spawn medium formula and culture conditions of Pleurotus geesteranus in submerged culture with shake flask were optimized according to the index of mycelia biomass,and enlarged in large scale culture in 7L fermentor.The results showed that the best carbon source and nitrogen source are soluble starch and peptone respectively.Consequently the optimal culture medium component was:20 g/L Soluble starch 5 g/L Yeast extract powder 1.2 g/L KH2PO4 0.8 g/L MgSO4·7H2O.Furthermore the optimum culture conditions were as follows:liquid medium volume 24%(v/v),initial pH 7,inoculation quantity 10%(v/v)and culture temperature 25??The biomass was increased 0.53g/L after optimized.Besides,the biomass was increased from 15.66g/L to 16.53g/L by culture in 7L fermentor,and the fermentation period is 6 days.Pleurotus geesteranus fermentation functional products contained polysaccharide protein flavone polyphenol and reducing sugar.The content of polysaccharide of Pleurotus geesteranus in fermentation broth was 0.672mg/mL bacterial leaching polysaccharide content in the solution of 0.312mg/mL.Flavonoid content of Pleurotus geesteranus in fermentation broth was 0.126 mg/mL 0.116mg/ml content of flavonoids in mycelium.Pleurotus geesteranus fermentation liquid and bacterial leaching solution of polyphenol content was 0.122 mg/mL 0.109mg/mL.The protein content of Pleurotus geesteranus in fermentation broth was 0.052mg/mL the protein content of infusion wa,s 0.031 mg/mL.The results of antioxidant abilities shows:fermentation liquor and extracting solution of mycelium of Pleurotus geesteranus showed strong reducting power.DPPH·scavenging ability reach the highest level in the 6th day,it was 44.1%?33.71%respectively.OH-scavenging ability also got the highest level in the 6th day,the result were 82.73%and 45.44%.O2-·scavenging ability of ermentation liquor and extracting solution of mycelium were 17.62%and 13.53%.