Restored Intensities from Customized Crops of NMR Experiments (RICC-NMR) to Gain Better Insight on Chemometrics of Sicilian and Sardinian Extra Virgin Olive Oils

The paper describes the application of mono-dimensional high-resolution nuclear magnetic resonance (NMR) spectroscopy to extra virgin olive oil (EVOO) samples to extract the chemical composition reasonably featured by specific genotype (cultivar) and detailed environmental conditions (terroir). To achieve this goal, we designed a suitable spectroscopic protocol made up of four NMR experiments: (I) standard 1H{13C}, (II) multiple pre-saturated 1H{13C}, (III) 1H selective excitation at 9.25 ppm, and (IV) 13C{1H} acquisition. The three 1H-NMR experiments (I–III) were merged into a single informative 1H-NMR trace. This “Restored Intensities from Customized Crops” (RICC-NMR) allowed us to extract, in just one 1H-NMR dataset, combined information about (a) main components, (b) less-represented components, and (c) minor but key-ruling secoiridoid species, respectively. Selected integrations of the RICC-NMR trace, together with selected integrations gathered from the 13C-NMR profile, led, for each sample, to the quantification of variables able to sort out distinct EVOOs. In this paper, this original methodology was applied to rationalize eighteen EVOOs from Sicily and nineteen from Sardinia, which were chemometrically compared and discussed.