Abstract: With the aim of optimizing the process conditions for the microwave-assisted solvent extraction of raspberry seed oil, this study was designed as follows: 1. For solvent selection, a comparison of raspberry seed oils extracted was carried out with different solvents such as ethanol, petroleun ether, n-hexane and ethyl acetate. 2. A series of one-factor-at-a-time experiments were conducted to investigate the effects of four operating parameters including solid/solvent ratio, temperature, extraction time and microwave output power on extraction efficiency of raspberry seed oil. 3. A mathematical predictive model for extraction efficiency of raspberry seed oil as a response to the four parameters was established by multiple polynomial regression with SAS software based on central composite design, and response surface analysis of the model was performed to probe into the pairwise interactive effects of various variables on their function. The above investigations showed that n-hexane was the best solvent for the extraction of raspberry seed oil, and that solid/solvent ratio of 1:10 (g/mL), temperature of 64 ℃, extraction time of 9 min and microwave output power of 657 W provided optimum extraction of raspberry seed oil, with an extraction efficiency of 17.73%.

Key words: red raspberry, microwave-assisted extraction, response surface analysis, raspberry seed oil