Abstract: An ultrasonic-assisted extraction method was developed for the extraction of procyanidins from Mulberry with ionic liquid solution as extracting agent.The extraction parameters (［Bmim］Cl concentration,solid to solvent ratio,ultrasonic power,ultrasonic time) were optimized by single-factor method and response surface methodology based on Box-Behnken design.The reasons for high efficiency of this extraction technology were analyzed by scanning electron microscope (SEM).The optimal extraction conditions were: the concentration of ［Bmim］Cl of 0.73 mol/L,solid to solvent ratio of 1:21(g/mL) ,ultrasonic power of 188 W,and ultrasonic time of 11 min.The extraction yield of procyanidins was 3.51%,which was well in close agreement with the value predicted by the model.The microcosmic structures of powders of Mulberry after being extracted by ionic liquid based ultrasonic-assisted approach were seriously destroyed from SEM analysis.

Key words: ionic liquid, procyanidins, mulberry, scanning electron microscope