Abstract: Microwave-assisted extraction(MAE)was used to extract essential oil (EO) from pomelo (Citrus grandis (L.)Osbeck) peel (CGP). Results show that petroleum ether is an optimal solvent and the extraction was affected mainly by stock mass ratio, microwave power, water content and granularity of material. The optimal conditions were obtained. Materials with granularity of 60 mesh and water content of around 7.4% are suitable for extraction. Total solvent-material mass ratio is 14:1. Extraction had to be performed twice with microwave irradiation (300 W) for 3 min each time. Crude EO was obtained after the extracted liquor was concentrated under vacuum. Crude EO was then dissolved with ethanol, frozen at -15℃ for 48 h, and centrifugally separated and filtered to get rid of impurities. The final product EO with yield of 2.09% and purity of 99.0% was then obtained after distilling the liquor under vacuum. Compared with direct-heating extraction (DHE), MAE reduced the extracting time up to 1/20.

Key words: microwave-assisted extraction, essential oil, Citrus grandis (L.) Osbeck peels