Volatile Profile in Greek Grape Marc Spirits with HS-SPME-GC-MS and Chemometrics: Evaluation of Terroir Impact

Greek grape marc spirits, although being traditional products, have lately attracted increasing attention as a revisited spirit product category. A headspace solid-phase microextraction coupled to the gas chromatography-mass spectrometry method was optimized in order to determine the volatile composition of 39 samples of grape marc spirits from eight major geographical regions of Greece and 4 protected designations of origin (PDOs). This untargeted analysis approach yielded the identification and quantification of 200 volatiles characterizing those products. Principal component analysis and partial least-squares-discriminant analysis (PLS-DA) combined with the volatile matrix were further employed to identify terroir denomination. Initial results showed a clear separation of the PDO products from Tyrnavos from the rest. Variable importance in projection data pretreatment was further adopted, and with 31 volatiles subsequently used with PLS-DA, products were correctly classified according to region of origin at 76.92% and for 3 out of 4 PDO denominations at 100%.