| In this paper, the antioxidant capacity of ginger extractions and the adsorption characteristic of polyphenol on different macroporous resin were researched.The preparation of ginger extractions and the scavenging ratio of hydrogen radical, superoxide radical and hydrogen peroxide by the ginger extractions was studied. The ginger extractions were gotten by the method of supercritical CO2extraction and solvent extraction. The ginger oleoresin, ginger essential oil and purified material in the former method were from the lab. The preparation of ginger extractions including solvent extraction, the separation, and purification of6-gingerol by macroporous resin were the experiment main content.This part of the main work and results were as follows:6-gingerol was separated by means of D4020macroporous resin column chromatography and analyzed by HPLC and UV. Firstly, the influence of process conditions on separation and the optimum chromatography conditions were discussed: column height25cm, flow rate1.0mL/min, and100mL of sample amount. Then further purification of the firstly separated gingerol sample was researched.The results of HPLC indicated that:the peak area percentage of gingerol had increased to85.24%and the yield of6-gingerol calculated with the HPLC results was86.11%after secondly purifiedOn the basis of the above work, the ginger extractions were used to make reseach on scavenging ratio of hydroxyl radical, superoxide radical, and hydrogen peroxide.The Fenton reaction was used to produce hydroxyl radical and the detection method was spectrophotometry. The optimal experiment conditions determined:pH3.50, reaction time20min, experiment temperature30℃, and detection wavelength670nm.Superoxide radical was from pyrogallol auto-oxidation action measured by the UV absorbance value of semiquinone at320nm. The results showed that the appropriate conditions were:temperature24℃, reaction time17-18min, and pH8.40-8.52.The evaluation of scavenging hydrogen peroxide was the method of cyclic voltammetry. The three electrode system was employed with a saturated calomel electrode (SCE) as the reference electrode, a platinum wire as the auxiliary electrode and a modified electrode (grapheme/nano-gold) as the working electrode. When the anodic peak was at0.39V, the concentration of hydrogen peroxide and current value had good liner relationship. So the content of hydrogen peroxide could be gotten from the fitting curve.The results of3radicals showed that ginger extractions had antioxidant capacity and the scavenging ratio had relationship with the concentration of ginger extractions. The phenols had better capacity of scavenging radical than zingerene. The work also reflected that the phenols had the best antioxidant capacity. There were also other compositions which can react with radicals expect6-gingerol.Secondly, the work was mainly on the adsorption and desorption characteristic including the adsorption isotherm and adsorption kinetics behaviour of polyphenol on different macroporous resin including HPD100, ADS-7, and D101macroporous resin. The conclusions were:The adsorption isotherm of polyphenol on HPD100, ADS-7, and D101macroporous resin could be described by Freundlich isotherm equation and n was equal to1.51,0.681, and0.648respectively.The adsorption kinetics models were:particle diffusion model could be used to describe the adsorption characteristic of polyphenol on HPD100macroporous resin; the second order kinetic reaction expressed the adsorption characteristic of polyphenol on ADS-7and D101macroporous resin. Equilibrated adsorption capacities calculated by the simulation equation were11.84mg/g,11.37mg/g, and8.13mg/g, while the results of experiment were12.09mg/g,11.20mg/g, and7.93mg/g.The conclusion was made that HPD100macroporous resin was suitable for the separation and purification of the polyphenol. |
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