Abstract: The essential oil from the yellow and purple skin onions was obtained by steam distillation,followed by solvent extraction,and analyzed by capillary GC-MS. The results showed that the yield of the essential oil from the yellow skin onion is 1.78%,and 20 compounds are identified. The yield of the essential oil from the purple skin onion is 3.24%,and 10 compounds were identified. The main chemical components of the extract from the yellow skin onion are found to be flavonoids,alkanes and amines compounds,while the main chemical components of the extract from the purple skin onion are found to be diethylene glycol bulk,diphenyl and dipropyl disulfide compounds.

Key words: onion, essential oil, GC-MS