Study On The Process Optimization,structure And Antioxidant Activity Of Polygonatum Polysaccharides By Ultra-high Pressure Extraction

Polygonatum sibiricum belongs to Liliaceae and its rhizome could be used as medicine.Modern pharmacology has confirmed that Polygonatum polysaccharide(PSP)has the functions of lowering blood fat,lowering blood sugar,antibacterial,improving immunity and anti-cancer.At present,the extraction method of PSP is mainly based on traditional extraction methods,and the ultra-high pressure extraction technology as an emerging extraction technology not only preserve the active substances in natural products,but also greatly shorten time of extract,save consumption of solvent and reduce the subsequent treatment process which has broad application prospects in the field of Chinese medicine extraction.In recent years,there are few reports about ultra-high pressure extraction of polysaccharide.In order to better enrich and improve the technological basis of ultra-high pressure extraction of polysaccharide and promote the industrial application process of this technology,the extraction rate of total sugar and PSP were used as indicators.The effects of process parameters on the PSP and total sugar were researched.The optimum process parameters of ultra-high pressure extraction of PSP were determined.As the same time,compared with traditional decoction method to verify the advantages of ultra-high pressure extraction technology.The physicochemical properties and the preliminary structure of ultra-high pressure extraction of PSP were studied.The in vitro antioxidant activity of PSP was studied by various methods.The main content was as follows:A standard curve for measuring sugar content by phenol-sulfuric acid method was established.The extraction rate of PSP and total sugar were used to analyze the effects of various factors on the PSP and total sugar;using the response surface experiment method,the optimization of extraction rate of the total sugar and PSP,the mathematical model of ultra-high pressure extraction of PSP was established.According to the predicted value of the best parameters,the optimal extraction conditions were as follow: pressure 255 MPa,solid-liquid ratio 1:17(g/mL),extraction time 9.5 min,under this conditions,the average sugar extraction rate of total sugar and PSP were 74.14%,25.01%,respectively.The prediction value was similar with experimental value which indicated that the model of ultra-high pressure extraction of PSP is reliable.Compared with the traditional decoction method,the results showed that the ultra-high pressure extraction method could obtain a higher extraction rate in a shorter time and lower temperature;the extracting solution of ultra-high pressure was lighter in color,lower in pigmentation,and the preservation time was much longer than the boiling method which indicated the feasibility,economy and process superiority of the ultra-high pressure extraction process,which provided a certain basis of theory and process for the comprehensive utilization of Polygonatum sibiricum.The physicochemical properties and preliminary structure of ultra-high pressure extracted PSP were analyzed by Zeta potential analyzer,XRD,UV spectrophotometer,Fourier infrared(FT-IR)spectrophotometer and gas chromatography.It was a pale yellow solid,the average particle size was about 6.151 ?m,its viscosity average molecular weight was about 300,000,which belonged to medium polysaccharide;UV spectroscopy showed that PSP contained little or no protein and nucleic acid;XRD indicated that PSP was an amorphous polymer;FT-IR showed PSP had typical characteristics of polysaccharide and contained pyran ring structure;The spectrum indicates that there are two types of terminal carbons;and the carbon signals of rhamnose,acetyl,pyranose and aldose existed in the structure of PSP;the ultrahigh pressure extracted PSP was composed of rhamnose,ribose,xylose,fructose,galactose and glucose by gas chromatograph;.Four kinds of external antioxidant experiments were used to assess the antioxidant activity of the ultra-high pressure extracted PSP,and compared with the antioxidant activity of Vc and the decoction extracted PSP.The results showed that the concentration of PSP was directly proportional to the scavenging rate of free radicals.The removal rate of different free radicals was different,and its scavenging ability was weaker than pure antioxidant Vc.However,the scavenging rate of free radicals of the ultra-high pressure extracted PSP were slightly higher than PSP by decoction which showed that the ultra-high pressure extraction method done not destroy the biological activity of PSP,and contained relatively few impurities which provided certain data support for the comprehensive development and utilization of PSP.