INSTITUTO DE INVESTIGACIONES EN BIOCIENCIAS AGRICOLAS Y AMBIENTALES
Unidad Ejecutora - UE
Authentication of Virgin Olive Oil using NMR and Isotopic Fingerprinting
ALONSO SALCES, ROSA MARIA; JOSE M. MORENO-ROJAS; MARGARET V. HOLLAND; CLAUDE GUILLOU
Nova Science Publishers, Inc.
Lugar: Hauppauge NY; Año: 2011 p. 60
In this study three harvests of virgin olive oils (VOOs) from the Mediterranean basin were analyzed by 1H NMR and 13C and 2H isotope ratio mass spectrometry (IRMS) to determine their geographical origin at the national, regional, or PDO level. An increase in 13C/12C and 2H/1H ratios was observed in VOOs from northern to southern regions; VOOs produced in France and northern Italy presented higher values than those produced in Spain and Greece. This trend was also observed in VOOs from northern and southern Italy, and for those from southern Spain and the other Spanish regions. Moreover, significant differences were found between years of harvest due to climatic conditions (rainfall, temperature) and, in some cases, between samples from the same region which could be due to such factors as orography, distance from the sea, or a particular microclimate. 1H NMR fingerprints of VOOs were analyzed by principal component analysis, linear discriminant analysis (LDA), and partial least-square discriminant analysis (PLS-DA). 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; for the non-Liguria class, 90 and 86% of hits were obtained, respectively. A stable and robust PLS-DA model was obtained to authenticate VOOs from Sicily: the recognition abilities were 98% for Sicilian oils and 89% for non-Sicilian ones, and the prediction abilities were 93 and 86%, respectively. More than 85% of the oils of both categories were well predicted in the external validation. Greek and non-Greek VOOs were properly classified by PLS DA: >90% of the samples were correctly predicted in the crossvalidation and external validation. Stable isotope data, that is, d13C and d2H, provided complementary geographical information to the 1H NMR fingerprints of the VOOs.