Extraction And Purification Of Gingerol From Ginger And Application Of Ginger Extract

Ginger,the rhizome of the Zingiberaceae plant,is widely planted in China.As early as ancient China,it has been used as seasoning and traditional Chinese medicine.It contains various active ingredients such as gingerol,flavonoids,and essential oil,and is a kind of medicinal and edible homologous plant.At present,ginger is mainly used as seasoning and medicine,but is not fully used in the extraction and purification process of gingerol from ginger and the application of ginger extract.So the ginger is selected as the research object in this dissertation,including the ultrasonic-assisted solvent extraction method being used to optimize the extraction process conditions of gingerol;macroporous resin being selected to explore the purification process parameters of gingerol;the synthesis of silver nanoparticles in the presence of ginger extract;the effect of ginger extract as a corrosion inhibitor.The comprehensive results provide an important basis and significance for the effective development and utilization of ginger resources.Ⅰ.The solvent extraction of gingerol from ginger under ultrasonic-assisted technologyAn ultrasonic-assisted solvent extraction method is used.Firstly,through a single factor experiment to explore the influence of different factors on the yield of gingerol in ginger,the response surface test was designed according to the results of single-factor experiment,and the extraction process of gingerol was optimized.Using vanillin as the reference substance,the gingerol concentration was measured at a wavelength of 280 nm to calculate the content of gingerol.The optimal extraction parameters were obtained as follows:ultrasonic time 123min,reflux temperature 87℃,liquid-solid ratio 35:1.Under these conditions,the actual yield of gingerol was 2.07%,and the content of gingerol in the ginger extract was 34.50%.Ⅱ.Purification of gingerol in ginger extract and determination of its antioxidant activityFirstly,D4020 macroporous resin was selected to study the adsorption and desorption of gingerol in the ginger extract.Then,the influences of different factors（loading solution concentration,loading solution p H,eluent concentration）on the purification process of gingerol were investigated.The comprehensive results show that the adsorption process of gingerol in the ginger extract by D4020 macroporous resin conforms to the pseudo-second-order kinetic model and Langmuir equation.The best purification parameters are followed as:the concentration of the sample solution is 0.67 mg/m L,the p H of the sample solution is 5,the loading volume of D4020 macroporous resin is 4.50 BV,the sample rate is3.5 BV/h,the eluent is 85 wt%ethanol,the eluent volume is 10 BV,the elution rate is 2.50BV/h.The purification process of gingerol was carried out under the optimized conditions,and the results showed that the content of gingerol increased from 34.50%to 51.30%.Then the antioxidant capacities of gingerols before and after purification were investigated,and Vitamin C（VC）was used as a control.The results showed that in the range of 0.10 to 0.60mg/m L,the antioxidant capacity was VC>after purification of gingerol>before purification of gingerol,but they all had good antioxidant capacity.Ⅲ.Preparation of silver nanoparticles assisted by ginger extractPreparation of silver nanoparticles assisted by the ginger extract.And the obtained samples were characterized by UV-vis,TEM,FT-IR,and other instruments.In addition,the gram-negative bacterium Proteus and the gram-positive bacterium Bacillus subtilis were used as test bacteria to explore the antibacterial effect of silver nanoparticles.The results show that silver nitrate can be reduced by ginger extract at room temperature,and silver nanoparticles with uniform size can successfully be synthesized.The optimum conditions were as follows:10 mmol/L ginger extract was 40 m L,5 mmol/L AgNO₃solution was 90 m L,and the stirring time was 36 h.At this time,the synthesized silver nanoparticles were uniformly distributed and had a significant inhibitory effect on all the tested bacterium.Ⅳ.The corrosion inhibition performance of ginger extract on Q235 steel in 1 M hydrochloric acidThe corrosion inhibition performance of ginger extract on Q235 steel was evaluated by weight loss method and electrochemical method（PC and EIS）in the range of 25～45℃,using ginger extract as a green corrosion inhibitor.The results showed that when the temperature was 40℃and the concentration of the ginger extract was 1.8 g/L,the highest inhibition efficiency was obtained by the weight-loss method and electrochemical method（PC and EIS）,which were 96.12%,99.84%,and 98.11%respectively.The adsorption isothermal model and adsorption isothermal thermodynamics of ginger extract on the surface of Q235steel were also discussed.The results revealed that the adsorption isothermal model was Langmuir adsorption isothermal equation.It was observed by a metallographic microscope that the corrosion of carbon steel surface was reduced by adding ginger extract.It also indicates that ginger extract is an excellent green corrosion inhibitor and has a strong inhibition effect on the corrosion of carbon steel.