Abstract: On the basis of one-factor-at-a-time experiments, response surface methodology was employed to the ultrasound-assisted extraction of synephrine from Citrus aurantium fruit. A quadratic regression model was established to investigate the extraction yield of synephrine with respect to three extraction parameters such as ethanol concentration, material particle size and ultrasound treatment time. The optimal extraction conditions determined were material particle size of 30 mesh, ethanol concentration of 67.90%, liquid-to-solid ratio of 12:1 (mL/g), extraction time of 16 min, and ultrasonic power of 420 W. Under these conditions, the extraction yield of synephrine was up to 5.87 mg/g, which was consistent with the predicted value of 5.77 mg/g. Thus, the established regression model had good feasibility.

Key words: Citrus aurantium, synephrine, ultrasound-assisted extraction, response surface methodology