Egyptian onion oil

The common onion (Allium cepa) belonging to the Lily family, is among the oldest known cultivated plants, and was cultivated in Egypt, China and India before the beginning of recorded history. Onion contains a volatile oil, fixed oil, protein, cellulose, sugars and minerals. The volatile oil content of onion depends on the variety of onion used and the distillation processes employed. The average yield is 0.015 percent oil. The chief constituents of the oil are di-n-propyl disulfide and dimethyl-n-propyl disulfide. Generally, one pound of the oil has the flavoring strength of 5,000 pounds of fresh onions or about, 500 pounds of dehydrated onions. This steam distilled oil contains numerous volatile components, mostly alkyl and allyl di- and tri-sulfides. We identified 32 of these chemicals using dual capillary column Gas Chromatography in combination with Gas Chromatography/Mass Spectrometry. The commercial significance of the oil and its full chemical analysis is discussed.