Virgin olive oil authentication by multivariate analysis of 1H-NMR fingerprints and d13C and d2H data

ALONSO-SALCES, R. M.; MORENO-ROJAS, J. M.; HOLLAND, M. V.; RENIERO, F.; GUILLOU, C.; HÉBERGER, K.

Journal of Agricultural and Food Chemistry

American Chemical Society

Año: 2010 vol. 58 p. 5586 - 5596

0021-8561

1H-NMR fingerprints of virgin olive oils (VOOs) from Italy, Spain, Greece, France, Turkey, Cyprus and Syria from 3 harvests were analyzed by principal component analysis, linear discriminant analysis (LDA) and partial least square discriminant analysis (PLS-DA), in order to determine their geographical origin at the national, regional or PDO level. Further d13C and d2H measurements, which are related to pedoclimatic factors, were performed on the oils by isotope ratio mass spectrometry (IRMS). LDA and PLS-DA achieved consistent results for the characterization of PDO Riviera Ligure VOOs. PLS-DA afforded the best model: for the Liguria class, 92% of the oils were correctly classified in the modeling step and 88% of the oils were properly predicted in the external validation; and for the non-Liguria class, 90% and 86% of hits were obtained respectively. d2H and d13C data did not significantly improve these classification models. At the regional level, a stable and robust PLS-DA model was obtained to authenticate VOOs from Sicily: in the cross-validation, the recognition abilities were 98% for Sicilian oils and 89% for non-Sicilian ones, and the prediction abilities, 93% for Sicilian and 86% for non-Sicilian class; and in the external validation, more than 85% of the oils of both categories were properly predicted. Depending on the region studied, stable isotopes can provide complementary geographical information to the 1H-NMR fingerprints of the VOOs. At the national level, a stable PLS-DA model was achieved to distinguish Greek VOOs. This model identified properly more than 97% of the oils of both categories, Greece and non-Greece, and predicted correctly more than 90% of the samples in the cross-validation, as well as in the external validation. Stable isotopes considerably enhanced the classifications of VOOs according to their country of origin. Moreover, the oxidative stability of VOO was also studied by 1H-NMR. The results achieved confirm that this analytical technique is a useful tool for the traceability of VOOs from different points of view, i.e. food authentication and food quality.