Geographical characterization of Italian extra virgin olive oils using high-field H-1 NMR spectroscopy

H-1 high-field nuclear magnetic resonance (NMR) was used to analyze 216 ext ra virgin olive oils collected in three years (1996, 1997, and 1998) in dif ferent Italian areas in order to evaluate the potential contribution of thi s technique to the geographical characterization of olive oils. A statistic al procedure performed on the intensity of selected NMR peaks has been prop osed. Tree clustering analysis of NMR data performed without any a priori h ypothesis showed the existence of reliable parameters able to group the oli ve oils according to the location of olive oil production. Linear discrimin ant analysis applied to selected NMR parameters of olive oils of the same y ear of production allowed the grouping of samples according to their geogra phical origin with only very few errors. Moreover, a satisfactory grouping is reached by combining the NMR data of olive oils from two different years (1996 and 1997). Operating on appropriate sampling, a careful analysis of data yielded the conclusion that the place of olive production could be sin gled out as a discriminating factor regardless of the cultivars from which the olive oils are derived.