Characterization of seven new hydrocarbon compounds present in the aroma of virgin olive oils

Seven isomeric hydrocarbons were detected in the volatile fraction of three samples of virgin olive oil. Chemical ionization mass spectrometry was used to assign the molecular formulas. Their structures were confirmed by comparison of retention time and mass spectral data with those of a synthetic sample obtained by pentene radical coupling. A final characterization of each chromatographic peak was done by means of a chiral capillary column to distinguish the optically active compounds from the isomers without chiral centers. For the quantitation the recovery factor in the oily matrix during the extraction of the volatile fraction was obtained using a related chemical, the commercially available beta-citronellene. On the basis of the previous literature and the present experiments a tentative rationalization of the involved biochemical pathway is proposed.