Extraction and Recovery of Flavonoids from Tartary Buckwheat Using Deep Eutectic Solvents

In recent years, the green extraction of natural active ingredients has generated widespread attention. And deep eutectic solvents have widely replaced traditional organic solvents. In this study, choline chloride/glycolic acid (1:2) was chosen as the optimal extractant to extract flavonoids from Tartary buckwheat. The optimal extraction conditions were as follows: water content of 30%, liquid-solid ratio of 40 mL/g, extraction temperature of 60 °C and extraction time of 40 min. And the extraction efficiency reached 27.22 ± 0.31 mg/g. Then kinetic and thermodynamic mechanisms were investigated comprehensively, and the results showed that the extraction process could be well fitted by Fick's second law. In addition, macroporous resins were used to recover flavonoids from extracts. The adsorption efficiency of flavonoids on HP20 resins under the optimal conditions (time of 2 h, liquid-resin ratio of 2.5 mL/g, temperature of 25 °C) could reach 80.14 ± 0.33%.