Universidade de Évora, Portugal
Extra virgin olive oil is a high-quality product and economically important for Portugal. According to official data, the Alentejo region is the main producing region being responsible for up to 80% of the national production. In order to protect Portuguese olive varieties, it is mandatory to have a full characterization of their olive oils.
In this work, 82 Portuguese olive oils from different varieties were studied using several analytical tools, aiming to discriminate among olive oils according to Variety. Olive oils were from Galega Vulgar, Madural, Cobrançosa, Carrasquenha, Blanqueta, Cordovil de Serpa, Verdeal Alentejana, Picual and Arbequina varieties. The last two ones were included since are among the most studied varieties in the world.
Fatty acids were determined by gas chromatography with a flame ionization detector (GC-FID). Volatile organic compounds (VOCs) were determined by headspace- solid phase microextraction and analyzed by gas chromatography coupled to mass spectrometry (HS-SPME-GC/MS). Nuclear magnetic resonance spectra were also obtained for the assessment of triacylglycerol fraction of the olive oils (1H NMR and 13C NMR DEPT 45).
Statistical analysis of data allow to verify the differences among the varietal olive oils. Results also shows that olive oils of Galega Vulgar variety are the ones clearly discriminated among all, regardless of the analytical procedure used.