Characterization of Olive Oil by Carbon Isotope Analysis of Individual Fatty Acids:  Implications for Authentication

Abstract

The fatty acids of olive oils of distinct quality grade from the most important European Union (EU) producer countries were chemically and isotopically characterized. The analytical approach utilized combined capillary column gas chromatography−mass spectrometry (GC/MS) and the novel technique of compound-specific isotope analysis (CSIA) through gas chromatography coupled to a stable isotope ratio mass spectrometer (IRMS) via a combustion (C) interface (GC/C/IRMS). This approach provides further insights into the control of the purity and geographical origin of oils sold as cold-pressed extra virgin olive oil with certified origin appellation. The results indicate that substantial enrichment in heavy carbon isotope (13C) of the bulk oil and of individual fatty acids are related to (1) a thermally induced degradation due to deodorization or steam washing of the olive oils and (2) the potential blend with refined olive oil or other vegetable oils. The interpretation of the data is based on principal component analysis of the fatty acids concentrations and isotopic data (δ13Coil, δ13C16:0, δ13C18:1) and on the δ13C16:0 vs δ13C18:1 covariations. The differences in the δ13C values of palmitic and oleic acids are discussed in terms of biosynthesis of these acids in the plant tissue and admixture of distinct oils. Keywords: Olive oil; carbon isotope; isotopic characterization; fatty acids; adulteration

Chemometric Analysis of Croatian Extra Virgin Olive Oils from Central Dalmatia Region

“…A number of studies tried to establish a relationship between composition and geographical origin using many different analytical techniques coupled in general with multivariate procedures. Chromatographic analytical techniques (gas chromatography, GC; with mass spectroscopy, GC-MS, and high performance liquid chromatography, HPLC) have been utilized to quantify major 32,33 and minor component classes. [34][35][36][37][38][39][40][41] There has been many studies in the recent years that used nuclear magnetic resonance [42][43][44] (NMR) with the aim to distinguishing olive oils of different geographical areas.…”

Statistical model for classifying the feeding systems of Iberian pigs through Gas Chromatography (GC-FID) and Isotope Ratio Mass Spectrometry (GC-C-IRMS)

“…However, the use of certain formulated feed in the fattening of pigs can mask the results, so it has resulted in the separation of fatty acid methyl esters (FAMEs) by Gas Chromatography and subsequent combustion and mass spectrometry analysis of the 13 C/ 12 C isotope ratios of the products obtained, which create a characteristic isotope profile of each sample (RecioHernández, 2010). This technique, called GCCIRMS, is currently used for the detection of adulteration in vegetable oils (Spangenberg et al 1998;Kelly et al, 1997, Kelly andRhodes, 2002) and wine (Regulation EEC, 1990). Although the method proposed for the Iberian pig indicates the determination of at least four isotopic ratios of the major FAMEs in the fat (oleic, palmitic, linoleic and stearic acids), which would be the minimum necessary to provide positive identification information in the case of an Iberian Acornfed pig (Bellota), some industries are currently using only the oleic 13 C/ 12 C isotope ratio for the differentiation of the Iberian pig feeding regime, applying an index which sets limit values for classifying the animals in the Bellota category.…”

The Application of Solution and Laser Ablation Based ICP-MS and Solution Based AES for the Provenance Determination of Selected Food and Drink Produce

“…Traditionally, studies on the geographical origin of olive oil are based on organic properties such as the concentration of organic components [26][27][28][29][30][31][32][33] or stable isotope compositions [34][35][36][37]. However, the determination of trace elements in an oil based matrix is extremely difficult as, prior to analysis, it is necessary to completely oxidize the oil.…”