title: Relationships between volatile compounds and sensory characteristics in virgin olive oil by analytical and chemometric approaches.
abstract: BACKGROUND
  The volatile fraction of virgin olive oil is characterised by low molecular weight compounds that vaporise at room temperature. In order to obtain an aroma profile similar to natural olfactory perception, the composition of the volatile compounds was determined by applying dynamic headspace gas chromatography, performed at room temperature, with a cryogenic trap directly connected to a gas chromatograph-mass spectrometer system. Samples were also evaluated according to European Union and International Olive Council official methods for sensory evaluation. In this paper, the composition of the volatile fraction of 25 extra virgin olive oils from different regions of Italy was analysed and some preliminary considerations on relationships between chemical composition of volatile fraction and sensory characteristics are reported.
  
  
  RESULTS
  Forty-two compounds were identified by means of the particular analytical technique used. All the analysed samples, classified as extra virgin by the panel test, never present peaks whose magnitude is important enough in defected oils. The study was focused on the evaluation of volatile compounds responsible for the positive impact on olive odour properties ('green-fruity' and 'sweet') and olfactory perception.
  
  
  CONCLUSIONS
  Chemometric evaluation of data, obtained through headspace analysis and the panel test evaluation, showed a correlation between chemical compounds and sensory properties. On the basis of the results, the positive attributes of virgin olive oil are divided into two separated groups: sweet types or green types. Sixteen volatile compounds with known positive impact on odour properties were extracted and identified. In particular, eight compounds seem correlated with sweet properties whereas the green sensation appears to be correlated with eight other different substances. The content of the compounds at six carbon atoms proves to be very important in defining positive attributes of extra virgin olive oils and sensory evaluation.
authors.affiliation: Department of Chemical and Pharmaceutical Sciences, University of Trieste, V. A. Valerio 6, 34127 Trieste, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Procida
authors.affiliation: Department of Economics, University of Chieti-Pescara, V. le Pindaro 42, 65127 Pescara, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Cichelli
authors.affiliation: Department of Economics, University of Genoa, V. Vivaldi 5, 16126 Genoa, Italy.
authors.forename: Corrado
authors.initials: C
authors.lastname: Lagazio
authors.affiliation: Department of Food Science, University of Udine, V. Sondrio 2/A, 33100 Udine, Italy.
authors.forename: Lanfranco S
authors.initials: LS
authors.lastname: Conte
mesh_terms: D005638:Fruit / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D007558:Italy; D009812:Odorants / Q000032:analysis*; D031658:Olea / Q000737:chemistry*; D055696:Olfactory Perception; D000069463:Olive Oil / Q000737:chemistry*; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D000069463:Olive Oil; D055549:Volatile Organic Compounds
keywords: chemometric evaluation; dynamic headspace analysis; gas chromatography-mass spectrometry; sensory evaluation; virgin olive oils