Study On Extraction Technology,Biological Activity Of Lentinus Edodes Polyphenols And Residue Utilization

Jiangxi Province is the main producing area of edible fungi in China,and Lentinus edodes is one of the main varieties planted in Jiangxi Province,with an annual output of200,000 tons.The added value of mushroom products is not high,because the mushroom is mainly processed by fresh selling and dry processing,and the processing utilization rate of waste mushroom and mushroom handle is low.In this paper,Lentinus edodes polyphenols were extracted from defective Lentinus edodes by ultrasonic-assisted technology.Based on single factor experiment and response surface methodology,the extraction process of Lentinus edodes polyphenols was optimized Antioxidant activity,hypoglycemic,lipid-lowering and antihypertensive effects of Lentinus edodes polyphenols were evaluated by scavenging free radicals,inhibiting key enzymes of type 2 diabetes,ACE enzyme,pancreatic lipase and cholesterol esterase.The main components of Lentinus edodes polyphenols were analyzed by LC-MS and HPLC.Meanwhile,polysaccharides were extracted and purified from residues and their composition and structure were studied.The purpose is to explore the feasibility of deep processing of Lentinus edodes and provide theoretical basis for enhancing the added value and comprehensive utilization of Lentinus edodes.The main research results are as follows:(1)The effects of ethanol concentration,solid-liquid ratio,extraction time,ultrasonic power and extraction temperature on the yield of Lentinus edodes polyphenols were investigated,and the optimum extraction parameters were as follows:ethanol concentration 50%,solid-liquid ratio 1:42(g/m L),extraction temperature 74?and ultrasonic power 146 W.Under these conditions,the yield of Lentinus edodes polyphenols was 10.91 mg/g,it shows that ultrasonic-assisted extraction is an effective method.The purity of crude polyphenol is 1.7%,and the purity of mushroom polyphenol is 41%after separation and purification by macroporous resin.(2)The components of Lentinus edodes polyphenols were analyzed by LC-MS,then the standard products were compared by HPLC,and the specific components were determined by standard addition experiment.Fourteen effective components were identified by the two technologies,the main components are myricetin,quercetin,kaempferol,rutin,gallic acid,catechin and ferulic acid,among which gallic acid and rutin have the highest content,which are 7.1 mg/m L and 5.12 mg/m L respectively,while ferulic acid has a lower content,which is 1.52 mg/m L.(3)Lentinus edodes polyphenols can inhibit key enzymes(?-amylase and?-glucosidase),angiotensin converting enzyme(ACE),porcine pancreatic lipase and cholesterol esterase in type 2 diabetes.The inhibitory rate of polyphenols on?-glucosidase was significantly higher than that of?-amylase with the inhibitory rates of 66.67%and56.35%respectively at the concentration of 4.5 mg/m L,and there was a significant difference between acarbose and polyphenols(P<0.05).Lentinus edodes polyphenol has inhibitory effect on ACE enzyme activity,the highest being 60.20%.The inhibition rate of Lentinus edodes polyphenol on pancreatic lipase activity was significantly higher than that of cholesterol esterase activity,which was 75.13%and 40.11%,respectively,and orlistat had the highest inhibition rate on pancreatic lipase activity,which was 89.71%.The inhibition rate of lentinan on cholesterol micelle solubility was 47.59%.The scavenging rate and reducing ability of VC on DPPH,ABTS~+and OH radicals were significantly higher than those of the crude extract and purified polyphenol of Lentinus edodes(P<0.05),and the scavenging rate of DPPH radicals between the crude extract and purified polyphenol of Lentinus edodes was significantly different(P<0.05).There was no significant difference in free radical scavenging rate between VC and purified polyphenol ABTS~+with increasing concentration(P>0.05).There was no significant difference in scavenging rate of OH radical between the crude extract and purified polyphenol of Lentinus edodes(P<0.05),which indicated that Lentinus edodes polyphenol had good antioxidant and digestive enzyme inhibitory effects in vitro.(4)Lentinan(LNT)was extracted from the residue,and the yield of crude polysaccharide was 10.3%.After deproteinization,decolorization and dialysis,LNT with purity of 68%was obtained.Ultrafiltering to obtain LNT1,LNT2,LNT3 and LNT4;with different molecular weights;The contents of total sugar,protein and uronic acid in LNT1were the highest,which were 40.07%,1.1%and 20.08%respectively.There are 9 kinds of monosaccharides in LNT1 and LNT2,but L-rhamnose is not detected.LNT3 and LNT4contain 10 kinds of monosaccharides and a small amount of L-rhamnose is 0.6%and0.37%,respectively.The content of D-glucose was the highest in LNT3(38.91%),and the content of D-galactose was the highest in LNT1(16.48%).FTIR analysis showed that the four components all contained?and?pyranoside bond structures.SEM analysis shows that LNT1 with large molecular weight has rough surface and fluffy structure,while LNT4with small molecular weight has smooth surface and compact structure.