Geographical origin, cultivar and harvesting year verification of European and non-European olive oils using proton transfer reaction mass spectrometry with multivariate data analysis

Volatile profiles of 308 extra virgin olive oil samples originating from four European and five non-European countries were used for oil authentication with respect to their geographical origin, the olive oil cultivar and the year of harvesting. The latter two were expected to provide some insight on the underlying factors of geographical origin classification. The composition of the volatile compounds in the headspace of virgin olive oils were analyzed by proton-transfer-reaction mass spectrometry (PTR-MS). The auto-scaled headspace concentrations of the masses were subjected to partial least square discriminant analysis (PLS-DA) in order to estimate classification models for the olive oil samples. Correct classification rates were assessed by double cross-validation. The models showed varying success rates. The larger the area/region was, the more successful the classification. Eighty-nine percent of the European oils were classified correctly, against 91% of the non-European oils. Success rates of Individual countries varied between 80 and 92. Additional models showed that cultivar determined to some extent origin classification, whereas year of harvesting had a minor influence. The present study shows that PTR-MS is a promising, rapid, non sample preparation requiring, technique for geographical origin determination of food samples.