Proton transfer reaction-mass spectrometry volatile organic compound fingerprinting for monovarietal extra virgin olive oil identification

Proton transfer reaction-mass spectrometry (PTR-MS) is a relatively new technique that allows the fast and accurate qualification of the volatile organic compound (VOC) fingerprint. This paper describes the analysis of thirty samples of extra virgin olive oil, of five different varieties of olive fruit (Arbequina, Cornicabra, Frantoio, Hojiblanca, and Picual) by PTR-MS. A multivariate pattern recognition method (partial least square-discriminant analysis, PLS-DA) was applied on the full spectra fingerprint of the PTR-MS measurements. The multivariate model was doubly validated: firstly by means of internal validation (cross-validation) and secondly with an external validation data set. The results showed that the five varieties could be successfully distinguished within them. The proposed method provides a new valuable tool for extra virgin olive oil classification according to variety, and it could serve as a screening technique for the authentication of monovarietal extra-virgin olive oil and as a methodology to confirm that a variety is in agreement with claimed identity.