An NMR (1H and 13C) and Isotope Ratio Mass Spectrometry (Delta 13C, Delta 2H and Delta 18O) study of Andalusian Olive Oils

Abstract

This paper deals with the determination of Delta13C, Delta 2H and Delta18O isotopic abundance in Andalusian olive oils. Moreover, the fatty acid composition, and the distribution of isomers at positions 1,3 and 2 of glycerol were determined by 1H and 13C NMR spectroscopy, respectively. Isotopic results obtained for four series of oil samples extracted from olives harvested in the 2004/05 and 2005/06 seasons are discussed in terms of olive variety, ripeness, geographic origin, fatty acid composition and growing altitude. A distinction was also established between olives grown in irrigated and dry land by studying selected samples of the previous series and others from the 2005/06, 2006/07, 2007/08 and 2008/09 seasons. Results showed that olive ripeness influences the abundance of none of the three isotopes studied. On the other hand, olive variety influences the abundance of the oxygen and hydrogen isotopes, and also, less markedly, that of carbon. No clear-cut effect of height or latitude on isotope values is observed, probably because olive variety does also change thus masking such influences. The oil samples from dryland-grown olives had increased Delta 13C values relative to irrigation-grown olives. Also, no definite relation appears to exist between isotope distribution and fatty acid composition. Finally oil samples from olives harvested in 2005/06 season in Italy could be distinguished from those from Spain in terms of their isotopic values (Delta 2H mainly).JRC.I.5-Systems Toxicolog