| Morchella umbrina a nutrient-rich edible mushroom..According to literature reports,there are 28 species of Morchella umbrina in 21 provinces of China.The humid provinces are more suitable for their growth.Morchella umbrina is mainly distributed in Linfen,Fenyang and Jiaocheng of Shanxi Province.Morchella umbrina polysaccharides have received widespread attention due to their good physiological activity.In the literature reported at present,the extraction of polysaccharides from Morchella umbrina is limited to one kind,and almost none uses different methods to study the extraction of polysaccharides.In this paper,water extracting method and ultrasonic assisted enzymatic method were used to extract Morchella umbrina polysaccharides.Deproteinization,decolorization and purification the crude polysaccharides.Three kinds of polysaccharides components(MUP-1,MUP-2 and MUP-3)were gained,and the components MUP-2 and MUP-3 with higher content were constructed.Analyze and study its antioxidant activity,the results are as follows:(1)The optimal process for extracting Morchella umbrina polysaccharides(MUPH)by hot water method could be concluded that: ratio of water to raw material,41:1(m L/g),the extraction temperature,88 ?,extraction time,3 h.Under this condition,the polysaccharides yield was4.24%.(2)The best process for extracting Morchella umbrina polysaccharides(MUPU)by ultrasonic assisted enzymatic method could be concluded that:ratio of water to raw material,22:1(m L/g),enzymatic hydrolysis,p H 4.0,enzymatic hydrolysis time,60 min,ultrasonic time,19 min,enzyme dosage,0.8 %.Under this condition,the polysaccharides yield was 7.79%.(3)Isolation and purification of Morchella umbrina polysaccharides:Deproteinization of MUPU,the protein removal rate of TCA method was77.27%,and the polysaccharides retention rate was 72.62%.The decolorization rate of AB-8 macroporous resin was 84.25%,and thepolysaccharides retention rate was 95.71%.Three polysaccharides fractions(MUP-1,MUP-2 and MUP-3)were purified by DEAE-52 cellulose gel and Sephadex G-100 dextran gel.(4)Structural analysis of the components MUP-2 and MUP-3 obtained by separation and purification: FTIR indicated that MUP-2 contained a pyran ring and MUP-3 contained mannose.The average molecular weights of MUP-2 and MUP-3 were determined by HPGPC to be 3833 Da and 5457 Da,respectively.MUP-2 was composed of D-mannose,D-glucose,D-galactose and D-arabinose in a molar ratio of 2.97:13.69:1:2.60;MUP-3 consisted of D-mannose,L-rhamnose,D-galactose and D-glucose,the molar ratio is18.25:0.84:1.53:1.The results of Congo red showed that MUP-2 has a double helix structure,while MUP-3 does not have this structure.Under the scanning electron microscope and atomic force microscope,MUP-2 showed a spherical structure,and MUP-3 was mainly in the form of a sheet.(5)Antioxidant activity of Morchella umbrina polysaccharides in vitro:The antioxidant capacity of MUPH,MUPU,MUP-2 and MUP-3 was evaluated by DPPH free radicals,hydroxyl radicals,superoxide anion radicals,ABTS free radical scavenging rate and reducing power in vitro.The results showed that MUPU was superior to MUPH in both free radical scavenging ability and reducing power;The ability of MUP-3 to scavenged DPPH free radicals,hydroxyl radicals,ABTS free radical scavenging ability and its reducing activity are higher,while MUP-2 has stronger ability to scavenge O2-ˇfree radical.The ability of MUP-3 to scavenge DPPH free radicals,hydroxyl radicals and ABTS radicals was 79.51%,89.62%,49.76%and 0.686,respectively,when the concentration of MUP-3 was 1 mg/m L.The clearance rate of superoxide anion removed by MUP-2 was 83.79%. |
PDF Full Text Request