| This paper conducts optimization research of alkaline extraction,deproteinization and decoloring technique of thesium polysaccharides through the response surface analysis and orthogonal experiment analysis in order to improve the practical value of thesium polysaccharide.Then separated and purified the crude thesium polysaccharide with DEAE-52 anion-exchange column and analyzed the structural features and antioxidation property.Research findings are as follows:1.Single factor experiment and response surface analysis shows that the The quadratic fitting equation of yield percentage,material-liquid ratio(A),extraction temperature(B),extraction time(C)and sodium hydroxide density(D)of thesium polysaccharide is:Y=-294.43208+0.79207A+2.97038B+70.64933C+240.34833D-0.0059AB+0.34AC+2.325AD-0.163BC-0.1425BD+2.6CD-0.040423A2-0.012281B2-16.81733C2-207.93333D2.Optimized extraction technique of thesium polysaccharide alkaline is: material-liquid1:33g/ml,extraction temperature 95?,extraction time 2h,sodium hydroxide density0.74mol/L.Actual extraction ratio is 20.86%,with relative deviation less than 1%.2.The research compared protein clearance rate and polysaccharide loss rate of Sevage method,trichloroacetic acid method and hydrochloric acid method and picked up trichloroacetic acid method at last.Optimizing the hydrogen peroxide decoloring technique via orthogonal experiment and the optimized process parameters are: decoloring temperature 60?,pH 8.5,add 6% hydrogen peroxide,decoloring time 2h.3.Crude thesium polysaccharide(TP)produced three coponents via DEAE-52anion-exchange column: TP-W,TP-1 and TP-3.Gas chromatography(GC)analysis of the crude TP and components showed that,TP-W is comprised of arabinose,xylopyranose,fructose,galactose,glucose and mannose,the ratios are 10.54%: 5.41%: 4.62%: 13.01%:30.38%: and 35.78% respectively,TP-1 is comprised of arabinose,xylopyranose,galactose and mannose,the ratios are 23.18%:25.64%:14.57%:and 36.50% respectively,TP-3 is comprised of arabinose,rhamnose,xylopyranose,galactose and mannose,the ratios are28.50%:16.00%:23.30%:11.79%:and 20.3% respectively.4.UV spectrum of TP-W,TP-1 and TP-3 showed that,no protein or nucleic acid impurities were found,polysaccharide is of high purity.The IR spectrum of TP-3 showed that,there exists obvious characteristic absorption peak of carbohydrate at 3400,2900cm-1 with features of pyranoid ring ? configuration anomeric carbon.5.This paper also tested the reducing capacity of thesium polysaccharide andclearance capacity towards DPPH and hydroxy free radicals.Findings showed that thesium polysaccharide has a strong antioxidant activity,TP-W has the stronger reducing capacity and clearance capacity of DPPH free radicals,TP-3 has the stronger clearance capacity of hydroxy free radicals,TP-1 and TP-W also displayed reducing capacity and clearance capacity.6.Static and dynamic laser scattering detection of TP-3 showed that the weight-average molecular weight is 3.819×107g/mol,molecular radical rotation radius is423.3nm,hydrodynamic radius is 983 nm,distribution dispersion exponent is 1.01 and molecular conformation tend to be spheral.7.TP-3 by Congo red test and transmission electron microscope,found that the microstructure of molecules mainly has the triple helical structure of spherical molecules,with laser scattering detection results. |
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