Abstract:Deep eutectic solvent（DES）was used to investigate the extraction effect of flavonoids from buckwheat hull.Firstly，six different components of DES were prepared to extract buckwheat hull flavonoids（BHFs），and the DES with the optimal extraction rate was screened out.The particle size and extraction temperature of buckwheat hull were determined by single factor experiment，and the water content in DES，liquid-solid ratio，and extraction time were optimized by response surface method to obtain the optimum extraction process parameters.The results showed that choline chloride/urea（molar ratio 1 ∶2）was the optimal DES for extracting BHFs.The particle size of buckwheat hull was 100 mesh，the extraction temperature was 70 ℃，and the optimum technological conditions were 35% water content in DES，liquid-solid ratio of 52 ∶1（mL/g），and extraction time of 2.8 h. Under these conditions，the extraction rate of BHFs was 4.79%，which was better than the traditional ethanol method.Therefore，DES can effectively improve the extraction rate of BHFs.