Abstract: In the extraction of volatile oil from pricklyash peel by microwave-assisted steam distillation (MASD), main extraction parameters were optimized by orthogonal assay design based on extraction efficiency with the purpose of developing a sample preparation method for rapid analysis of volatile oil composition of pricklyash peel by gas chromatography-mass spectrometry (GC-MS). The effects of MASD and single steam distillation on the extraction efficiency, physicochemical properties and chemical composition of volatile oil from pricklyash peel were compared. The optimal MASD parameters were determined as follows: microwave power 400 W, extraction time 20 min, and the amount of water addition 15 mL/g. Totally, 137 compounds were separated in the GC-MS analysis of volatile oil extracted by MASD, and 59 of them had higher than 90% mass spectral similarities, including the dominant compounds sabinene (3.72%), beta-myrcene (8.34%), sylvestren (15.15%), terpinene (3.65%), cineole (6.25%), alpha-pinene (4.95%), beta.-linalool (3.05%), 4-carvomenthenol (10.48%), alpha-terpieol (3.55%) and alpha-terpineol acetate (4.09%), which were quantitatively determined by peak area normalization method. Volatile oils extracted by both methods had similar compound composition and physicochemical properties but differed in the relative contents of their common components. In summary, an efficient and effective extraction of volatile oil can be achieved by using MASD. Volatile oil composition can be rapidly analyzed by MASD coupled with GC-MS.

Key words: pricklyash peel (Zanthoxylum bungeanum), volatile oil, microwave assisted extraction, gas chromatography-mass spectrometry (GC-MS)