Extraction,Purification Of Glycyrrhizic Acid And Preparation Of Its Structural Analogs

Glycyrrhizic acid is the main component of the sweetness of licorice.The advantage of using glycyrrhizic acid instead of sucrose to process functional foods such as low sugar or sugar is becoming more and more important.At present,the research on the structural modification of glycyrrhizic sugar chains to improve the sweetness is rare.The glycosylation modification of compounds can be used as an effective means for the development of functional sweeteners.The main research work is as follows:According to the national standard and literature method,the basic components of licorice were determined as follows:moisture content was 5.80%±0.03%,ash content was 2.37%±0.02%,fat content was 1.68%±0.01%,and crude fiber content was 9.29%±0.04%.The protein content was 8.24%±0.06%,and the total flavonoid content was 7.76%±0.07%.The main component of the study was glycyrrhizic acid content 5.34%±0.05%,and the remaining carbohydrate was 59.52%±0.04%.The effects of ethanol concentration,extraction time,solid-liquid ratio and extraction temperature on ultrasonic-assisted extraction of glycyrrhizic acid were investigated by single factor and orthogonal experiments.The optimal conditions were as follows:ethanol concentration 65%,time 50 min,ratio of material to liquid 1:40(g·mL-1),temperature 65?,extraction rate 84.35%±0.08%.The macroporous adsorption resin method was used to purify the glycyrrhizic acid,and the process of purifying the glycyrrhizic acid from the macroporous resin was optimized.The result was that D101 macroporous adsorption resin was used,the loading amount was 3 BV,the sample pH was 6.0,and the eluent was used.The ethanol concentration was 70%,the dosage was 3 BV,and the glycyrrhizic acid was preliminarily purified under the conditions.The yield was 61.98%.The purity of the crude product was greatly improved by HPLC,and the glycyrrhizic acid content was calculated to be 65.69%.It was further refined by recrystallization.Glycyrrhizic acid has a high purity,and the glycyrrhizic acid content is calculated to be 93.80%,and the total yield is 46.31%.Two glycyrrhizic acid glycoside derivatives were prepared by glycosidation method:methyl glycyrrhetinate-glucoside(yield:57.32%),glycyrrhetinic acid methyl ester-galactoside(yield:59.73%),utilized Thin layer chromatography,specific rotation,nuclear magnetic resonance and mass spectrometry were used to verify the structure of the compound.The sweetness of glycyrrhizic acid and its structural analogues were compared by sensory evaluation.The sweetness of methyl glycyrrhetinate-glucoside was higher than that of glycyrrhizic acid,while the sweetness of methyl glycyrrhetinate-galactoside was It is slightly lower than glycyrrhizic acid,but also much sweeter than sucrose.To study the effect of glycyrrhizic acid and two structural analogues on a-glucosidase inhibitors by establishing an enzyme-inhibitor screening model.The methylglycyrrhetinate-galactosidase was used at a concentration of 1 mg·mL-1 for a-glucosidase.The inhibitory effect exceeded glycyrrhizic acid,and the glycyrrhetinic acid methyl ester-glucoside was slightly worse,but at a concentration of 4 mg·mL-1,it also had a higher inhibition rate of 81.74%,and there was a dose-effect relationship.