Optimization of Extraction Process for Total Flavonoids from Buckwheat by Response Surface Analysis

The extraction of total flavonoids from Fagopyrum of Miqiao 1 was optimized.based on one-factor-at-a-time experiments.The effects of extraction temperature,extraction time,material-to-liquid ratio and ethanol concentration on the extraction rate of total flavonoids from buckwheat were investigated.A 4-variable,3-level was generated by the Design-Expert 7 software and experimental data obtained were subjected to quadratic regression analysis to create a model to find optimal conditions for the extraction of total flavonoids.The optimal extraction conditions were found as: ethanol concentration 69%,material-to-liquid ratio 1:42(g/mL),extraction temperature 68.5 ℃ and extraction time 90 min.Under these conditions,the predicted and experimental extraction rate of total flavonoids were 2.291% and 2.157%,respectively.The deviation between the predicted and experimental extraction rate of total flavonoids was small,showing that this method applied to optimization of extraction process for total flavonoids from buckwheat is feasible.