Agriculture: Extra virgin olive oil, ENEA studies olives' traceability

ENEA researchers have developed a method to identify pure extra virgin olive oil through the traceability of the geographical origin of the olives based on the content of elements. The outcomes of the study were published in the open source journal ‘foods’.

ENEA researchers have developed a method to identify pure extra virgin olive oil through the traceability of the geographical origin of the olives based on the content of elements. The outcomes of the study were published in the open source journal 'foods'.

The study was conducted on thirty-seven samples of olives and leaves from eleven species of olive tree[1] focusing on the analysis of the chemical elements present. The samples of olives (drupes) and olive leaves were collected in two different production areas in Lazio: the ENEA Casaccia Research Center and the municipality of Allumiere, where five different olive groves were selected based on cultivars[2] and production sites.

“By combining state-of-the-art analytical technologies we were able to identify the geochemical signature of the soil transferred to the olives. This opens up the possibility of identifying, faster and more accurately, the geographical origin of olive products and 'find out' possible frauds especially among the PDOs which must guarantee quality, authenticity and typicality strictly related to the production area", explained Claudia Zoani, researcher at the Biotechnology and Agro-industry Division.

The ENEA team employed high sensitivity analytical techniques[3], which also allow to quantify the elements found in very low concentrations. “We also used a technology developed at the Frascati Research Center, a portable device based on photoacoustic laser spectroscopy[4] which uses light and sound to perform non-destructive measurements in real time on the untreated sample .

Due to these characteristics, the ENEA laser has already been successfully used both in horticulture to detect the attack of pathogenic agents and to detect food fraud in products such as powdered milk, honey, wine, oil, fruit juices, fish and some spices. The tests carried out on the olive leaves with the laser system, based on molecular type spectra, confirmed the groupings by geographical area obtained with the elemental analysis”, said Zoani.

Specifically, the results of the elemental analysis showed the possibility of distinguishing the samples of olives and leaves by production area, based on different soil’s characteristics. The most abundant elements in the olive groves of the ENEA Research Center were strontium (13 mg/kg) and copper (13.44 mg/kg). The area of Allumiere showed a higher content of rubidium (12.86 mg/kg) and, subsequently, of copper (11.36 mg/kg) and strontium (6.74 mg/kg). Furthermore, having five experimental fields in the same production area allowed to compare more accurately the behavior of the same varieties in the different fields[5].

“In addition to establishing the geographical origin of the olives, the analysis of the concentrations of the elements in the drupes could also be a soil pollution indicator. But further studies are needed to evaluate which soil characteristics can influence the presence of the various elements in olives and verify how their bioavailability can be affected, for example, by the use of fertilizers or fungicides. All this will help ensure a wider applicability of the ENEA method for geographical traceability in different cultivation conditions, together with assessments pertaining food safety”, Zoani pointed out.

The Mediterranean basin is the largest world olive growing area: Spain (63%), Italy (17%), Greece (14%) and Portugal (5%) cover 99% of Europe's olive oil production which holds the record for olive and olive oil production (69% of global production), export and consumption. In addition to the economic value, olive products are the basis of the Mediterranean diet and have a high nutritional and curative power. Their consumption is a protective factor against diabetes and heart, inflammatory and autoimmune diseases, thanks to the high levels of monounsaturated fatty acids, phenolic compounds and antioxidants. Even their by-products have a high value; for example, olive leaf extract is used as a food additive due to its high content of polyphenols with antioxidant and antimicrobial activity.

Claudia Zoani, ENEA – Biotechnology and Agro-Industry Division, 

“Characterization and Discrimination of Italian Olive (Olea europaea sativa) Cultivars by Production Area Using Different Analytical Methods Combined with Chemometric Analysis” https://doi.org/10.3390/foods11081085

[1] The cultivars Cipresso, Canino, Frantoio, Leccino, Maurino, Moraiolo and Pendolino for oil, the Ascolana and Uovo di Piccione for table olives and the Itrana and Ortice for both.

[2] In agronomy a variety of cultivated plant.

[3] Plasma Induced Atomic Emission Spectroscopy (ICP-AES) and Plasma Induced Mass Spectrometry (ICP-MS).

[4] LPAS - Laser Photo-Acoustic Spectroscopy

[5]  For example, the drupes of field A5 have a higher concentration of copper, vanadium and chromium and the olives of field A3 and A4 a higher content of rubidium and cobalt. Titanium and zinc were the most abundant elements found in area A1.