Optimization of Extraction Technique of Flavonoids from Garlic by Response Surface Methodology

Objective: Response Surface Methodology(RSM) is used to optimize the extraction technology of flavonoids from garlic.Methods: To optimize extraction yield of total flavonoids,extraction time,solid-liquid ratio,ethanol concentration and extraction temperature are selected as four influencing factors during extraction.The experiment mathematical model is arranged according to Design-Expert central composite experiment design.These factors are studied on influences of flavonoids extraction yield.Results: The influencing factors in the descending order are as follows: extraction temperature,ethanol concentration,extraction time and solid-liquid ratio.The optimum extraction conditions are as follows: extraction time of 3.98 h,solid-liquid ratio of 1∶40.19,ethanol concentration of 68.63%,extraction temperature of 96.66 ℃.The extraction rate of flavonoids is 1.134 mg/g,under the optimum conditions,the actual extraction rate determined by Ultraviolet Spectrophotometry is 1.122 mg/g,and the actual extraction rate determined by Fluorescene Method is 1.127 mg/g.Conclusion: The extraction technology of flavonoids optimized by Response Surface Analysis is stable,reasonable and feasible.