Abstract: In this study,45 ^oC dried lemon peel was used as raw material to extract the bitter element by ultrasonication using ethanol as extraction solvent.The effects of ethanol concentration,liquid solid ratio and ultrasonic treatment time on the extraction yield of bitter element were studied.The response surface methodology was used to design experimental program.The optimized extraction conditions were obtained as follows:the ethanol concentration was 70%,liquid solid ratio was 15:1 and ultrasonic treatment time was 35min.Under these conditions,the average extraction yield of bitter element was determined to be 1.721 mg/g with good reproducibility.The results of this study provided reference data for the extraction and utilization of limonin.

Key words: limonin, lemon peel, response surface methodology, ultrasonic extraction