Comparison of triacylglycerol analysis by MALDI-TOF/MS, fatty acid analysis by GC-MS and non-selective analysis by NIRS in combination with chemometrics for determination of extra virgin olive oil geographical origin. A case study

Synergy of analytical methods based on chromatography, mass spectrometry and spectroscopy combined with chemometrics was tested in the herein presented pilot authentication study of Croatian extra virgin olive oils (EVOOs). Fatty acid (FA) composition was determined by gas chromatography-mass spectrometry (GC-MS), triacylglycerol (TAG) composition by matrix-assisted laser desorption ionization time-of-flight/mass spectrometry (MALDI-TOF/MS), and non-selective analysis was done by near-infrared spectroscopy (NIRS). Chemometric methods were applied on measured data where TAG and NIR spectra showed the highest potential for geographical origin discrimination. TAG profiling data had the best classification power for EVOOs in the PCA, whereas PLS-DA models with high classification accuracy were based on NIRS significant variables or TAG data. Furthermore, NIRS data proved valuable in prediction of quality parameters. Therefore, we presented NIRS as quick, cheap and reliable technique for authenticity study of EVOOs, but for complete characterization of olive oils MALDI-TOF/MS was indispensable.