Olive Oil Traceability Studies Using Inorganic and Isotopic Signatures: A Review

Abstract

The olive oil industry is subject to significant fraudulent practices that can lead to serious economic implications and even affect consumer health. Therefore, many analytical strategies have been developed for olive oil’s geographic authentication, including multi-elemental and isotopic analyses. In the first part of this review, the range of multi-elemental concentrations recorded in olive oil from the main olive oil-producing countries is discussed. The compiled data from the literature indicates that the concentrations of elements are in comparable ranges overall. They can be classified into three categories, with (1) Rb and Pb well below 1 µg kg−1; (2) elements such as As, B, Mn, Ni, and Sr ranging on average between 10 and 100 µg kg−1; and (3) elements including Cr, Fe, and Ca ranging between 100 to 10,000 µg kg−1. Various sample preparations, detection techniques, and statistical data treatments were reviewed and discussed. Results obtained through the selected analytical approaches have demonstrated a strong correlation between the multi-elemental composition of the oil and that of the soil in which the plant grew. The review next focused on the limits of olive oil authentication using the multi-elemental composition method. Finally, different methods based on isotopic signatures were compiled and critically assessed. Stable isotopes of light elements have provided acceptable segregation of oils from different origins for years already. More recently, the determination of stable isotopes of strontium has proven to be a reliable tool in determining the geographical origin of food products. The ratio 87Sr/86Sr is stable over time and directly related to soil geology; it merits further study and is likely to become part of the standard tool kit for olive oil origin determination, along with a combination of different isotopic approaches and multi-elemental composition.

Heavy metals, rare earth elements and isotopic fingerprint of Venetian Protected Designation of Origin sparkling wines

“…Also, Pb has four stable isotopes, and it comes from the soil, but its natural concentration in plants is low. The Pb accumulation in plants was strictly related to a contaminated environment due to anthropogenic activity, such as mining, industry, coal-burning and gasoline (Nasr et al, 2022). All these factors enable Sr and Pb isotopes as suitable markers of specific geographical situations.…”

Properties and chemical compositions of monovarietal virgin olive oil at different ripening stages: A study on olive cultivation in Northwest China

“…Nevertheless, the suitable regions for olive cultivation in China still have considerably distinct weather and soil conditions that are similar to those of the Mediterranean Basin (e.g., local olive trees experience more rainfall and less solar radiation during the flowering and fruiting stages). Consequently, VOO from the same cultivar produced under different geographical and climatic parameters may differ in yield per acre and chemical character/composition (Nasr et al., 2022; Rodrigues et al., 2023).…”

Identification of Turkish extra virgin olive oils produced in different regions by using NMR (1H and 13C) and IRMS (13C/12C)

“…It was shown that the isotopic fractionation of the elements for the geographical discrimination of olive oil is highly correlated with the geographical and climatic parameters (Nasr et al, 2022). NMR technique has many advantages such as; high reproducibility, profitable use for fingerprint analysis, fast measurement, minimal sample preparation, long-term sample storage, and suitable for untargeted and targeted analysis and many components and quality characteristics can be simultaneously analyzed in a few minutes at the same time (Emwas et al, 2019).…”