Targeted analysis for detection the adulteration in extra virgin olive oil's using LC-DAD/ESI-MS/MS and combined with chemometrics tools

The hand-held LC-DAD/ESI-MS/MS approach was employed, for the first time, for the quantification of extra virgin olive oil (EVOO) adulteration with refined pomace olive oil (RPOO). The total polyphenols (TP) and sterols were quantified according to their chemical methods, with more reliable methods required in this field to avoid undue dependence on chlorophylls, carotenoids contents and antioxidant activity (DPPH assays), which were evaluated by spectrophotometric methods. Some differences concerning the antioxidant activity and the TP content were observed. Actually, Chemlali EVOO activity was the most pronounced (13.84 +/- 0.21%) and it contained the highest TP content (284.54 +/- 4.27 mg/kg). Indeed, a correlation between antioxidant activity, TP and oxidative stability was established herewith. The metabolomics data were elaborated with the help of chemometric tools i.e. principal component analysis (PCA) and hierarchical cluster analysis (HCA). This approach allowed the estimation of the best discrimination markers for EVOO authenticity evaluation (i.e. Hydroxytyrosol quinone, oxidized hydroxytyrosol, 3,4-DHPEA-EA, p-HPEA (tyrosol), p-coumaric acid, luteolin, decarboxymethyl 10-hydroxyoleuropein aglycon, beta-sitosterol apparently; campesterol, stigmasterol, increment Delta-7-stigmastenol and increment Delta-7-avenasterol). [GRAPHICS] .