Study On Separation And Purification Of Glycyrrhizic Acid

Licorice is a legume plant that contains many active ingredients.Among them,glycyrrhizic acid is one of its main active components,which has important applications in food,medicine and other fields.In order to find a process route of high purity glycyrrhizic acid,this paper studied the extraction and purification process of glycyrrhizic acid by using urals licorice as raw material.The process provides a solid theoretical basis for the industrial production of high purity glycyrrhizic acid.Taking glycyrrhizic acid extraction rate as an index,this research optimizes the technological conditions of extraction of glycyrrhizic acid from Licorice by two-stage method of combined enzymes and ultrasonic.When the mass of glycyrrhizic acid is 1 g,the optimum technological conditions for the enzymatic stage are as follow:the optimal ratio of combined enzymes(pectinase:cellulose)is 1:3(U/U);the dosage of combined enzymes is 175 U/g·substrate;the pH is 5.5;the reaction time is 1 h;the reaction temperature is 50?;the particle size of raw material is 40 mesh;the ratio of material to liquid is 1:25(g/mL).The optimum technological conditions for the ultrasonic stage are as follow:the ultrasonic extraction solvent is 20%ethanol,and the ratio of material to liquid is 1:35(g/mL);the ultrasonic power is 350 W;the ultrasonic time is 15 min;the ultrasonic temperature is 40?.Under these optimum conditions,the extraction rate of glycyrrhizic acid can reach(90.44±0.14)%.Taking adsorption rate and desorption rate as indicators,the optimal resin HPD722 for the preliminary purification of glycyrrhizin was selected from 7 macroporous adsorption resins,and the dynamic adsorption and desorption process conditions of the resin were studied.The results showed that the optimal dynamic adsorption conditions of HPD722 are as follow.The optimum sample weight is 7 BV;the concentration of the sample is 6.5 mg/mL;the pH of the sample is 7.0;and the flow rate of the sample is 3 BV/h.The optimal dynamic desorption condition of HPD722 are as follow:the optimal concentration of ethanol is 70%;the volume of the eluent is 3 BV;the flow rate of the eluent is 2 BV/h.Under the optimal dynamic adsorption and desorption conditions,after the 30.07%glycyrrhizic acid was purified by HPD722,the purity of glycyrrhizic acid is up to(70.65±0.62)%and the yield is up to(80.50±0.51)%.The glycyrrhizic acid purified by HPD722 is decolorized by activated carbon and 95%alcohol,and the purity of glycyrrhizic acid is up to 76.96%.Using ethanol recrystallization to make further purification and studying the optimum process conditions,the results showed that the optimum process conditions are as follows.The best concentration of ethanol was 100%,the material liquid ratio 1:15(g/mL),crystallization temperature 24?,the crystallization time 24 h,recrystallization number 5 times.Under the optimal recrystallization process,the purity of glycyrrhizic acid is increased to(95.22±0.32)%and the yield is up to(54.30 ±0.43)%.