Olive oil characterization and classification by 13C NMR with a polarization transfer technique: A comparison with gas chromatography and 1H NMR.

ABSTRACT

In a previous work, we optimized and used a fast adiabatic 13C-INEPT (Insensitive Nuclei Enhanced by Polarization Transfer) experiment for the isotopomic analysis of olive oil samples, which allowed us quantifying individual fatty acids within triacylglycerols through multivariate linear regression models. The goal of this study was to validate these models and to evaluate the power of 13C-INEPT in the authentication of olive oils relative to gas chromatography (GC) and 1H NMR. In this respect, a new set of olive oil samples was analyzed by these three techniques. The analytical variables thus obtained as well as their corresponding long-term repeatability were compared. As a result, the reliability of the fatty acid quantification models was proven and the best classification of olive oils according to the altitude of the olive grove and to the morphological aspect (color) of the olives was achieved by means of 13C-INEPT.