Reliable classification of olive oil origin

Method allows differentiating the origin of olive oils from Italy, Greece and Spain

March 2023 (update). Although according to European Regulation (EU) No 2022/2104 it is mandatory to declare the geographical origin of olive oil on the label, no generally accepted analytical method exists to verify this labelling. Mislabelling of olive oil with respect to its geographical origin is a frequently encountered fraud.

Therefore, Eurofins developed a method based on the determination of the minor components of olive oil by 1H-NMR analysis ("Minor Component Profile"). The method allows to distinguish the three main producing countries in the Mediterranean Area, Italy, Greece and Spain and can be reliably applied to routine samples.

One method – several fields of application

The method has proven very useful in assessing the geographical origin of olive oils. In addition, the 1H-NMR profiles obtained through this protocol can be used for further applications, for example, the quantitation of polyphenols or relation with sensory attributes (bitterness, pungency, fruitiness).

The special features of the method

Darstellung eines Modells, das auf 95% der Daten basiert mit den projizierten Ergebnissen des jeweiligen Testsatzes

Plot of a model based on 95% of the data with the projected results of the respective test set.

NMR clearly shows promise in accomplishing a differentiation between oils from different origins, but mainly gives information on the fatty acid composition which does not seem to be suitable for the differentiation on the country level. Therefore, the minor components of olive oil were examined in more detail.

Minor constituents are mainly phenolic compounds (e.g., phenols, aldehydes, or ketones), which can be enriched in the process by simply employing an extraction with a polar solvent like acetonitrile (ACN) and direct analysis. This makes sample preparation considerably easier and, due to its robustness, enables high throughput.

Reference data and validation of the results

A total of over 1000 samples of extra virgin olive oil from Italy, Greece and Spain were collected and analysed for the reference database. These samples represent the main production areas and varieties.

The classification model developed from these samples achieved an overall accuracy of 96% in the cross-validation tests. The method is being routinely applied for testing commercial off-the-shelf olive oils, and its accuracy is continuously verified.

The performance of the method was also documented in a ring test, where the origin of three correctly labelled samples (Italy, Spain, Greece) could be confirmed, whereas two incorrectly labelled samples (Italian oil labelled as Greek, Greek oil labelled as Spanish) were clearly identified.

Do you have questions about olive oil analysis?

Here you will find further information. If you have any questions about the new method of classification of the origin of olive oil, please contact our olive oil experts.

For further information

The method was discussed in detail in the European Journal for Lipid Science and can be purchased here:

Reliable Classification of Olive Oil Origin Based on Minor Component Profile Using ¹H‐NMR and Multivariate Analysis