A new study published in ‘Agriculture’ analyses 25 extra virgin olive oils of the ‘Picual’ variety and demonstrates that altitude causes systematic changes in their fatty acid and triglyceride profiles, opening up new possibilities for the geographical authentication and differentiation of mountain-grown olive oils.
The University Institute of Research on Olive Grove and Olive Oils (INUO) at the University of Jaén continues to make progress in generating and transferring scientific knowledge applied to one of the main challenges facing the olive oil sector: understanding, characterising and assessing the influence of the territory on the quality and characteristics of virgin olive oils.
A new scientific publication, entitled “Altitude-Driven Variations in the Lipid Profile of Extra Virgin Olive Oil: A chemometric Approach for Geographical Authentication”, analyses the relationship between altitude and the lipid composition of extra virgin olive oil (EVOO), providing evidence of how environmental conditions associated with elevation can leave an identifiable chemical signature in the oil.
The study involves researchers affiliated with INUO, including Cristina Sánchez-Quesada and José Juan Gaforio from the Health Unit, alongside researchers from ‘IFAPA Venta del Llano’ and collaborators from the Process Engineering, Biochemistry and Cellular Stress, and Analytical Chemistry Units: María de la Paz Aguilera, Gabriel Beltrán, Abrahan M. Gila, Araceli Sánchez and Antonio Jiménez.
Altitude as a determining factor in the composition of the oil
The study addresses a question of particular interest for the characterisation and promotion of mountain olive oils: To what extent can altitude alter the chemical composition of extra virgin olive oil (EVOO) and serve as an indicator of its geographical origin?
To answer this question, the researchers analysed 25 oil samples from olive groves where the ‘Picual’ variety predominates, situated between 450 and 1,045 metres above sea level, with plots located in the provinces of Jaén, Málaga and Córdoba, including a broad representation of olive groves from Jaén.
Using chromatographic techniques, 37 lipid parameters were studied, including 13 individual fatty acids and 24 triglyceride species. The results were subsequently analysed using chemometric tools such as linear discriminant analysis (LDA) and principal component analysis (PCA), with the aim of identifying patterns associated with altitude.
The results show that altitude causes systematic and quantifiable changes in the lipid profile of extra virgin olive oil.
Higher levels of oleic acid and a lower proportion of saturated fatty acids at higher altitudes
One of the main findings was the existence of a significant relationship between altitude and the overall fatty acid composition. As altitude increases, the proportion of saturated fatty acids decreases and that of monounsaturated fatty acids increases. Specifically, saturated fatty acids fall from an average of 15.72 per cent in oils from lower altitudes to 14.59 per cent in oils from higher altitudes, whilst monounsaturated fatty acids rise from 78.97 per cent to 81.69 per cent.
Among the various compounds analysed, oleic acid (C18:1) – the main component of olive oil – stands out in particular. Its concentration rises from 77.55 per cent in samples from lower altitudes to 80.57 per cent in those from higher elevations, showing a positive and statistically significant correlation with altitude.
Conversely, palmitoleic acid (C16:1) exhibits the strongest negative correlation with altitude, falling from 1.11 per cent to 0.84 per cent. According to the researchers, this behaviour makes it one of the possible chemical markers for characterising oils from mountainous areas.
These changes are linked to the effect of temperature conditions associated with altitude on the metabolic pathways involved in fatty acid biosynthesis, particularly on the activity of desaturase enzymes.
The chemical signature of altitude is also reflected in triglycerides
The study is not limited to the analysis of fatty acids, but also incorporates the analysis of triglycerides (TAG), providing a more comprehensive view of the oil’s lipid profile.
The results show that certain types of triglycerides increase or decrease systematically with altitude. Of particular note is the OOO+PoPP fraction, which increases from 47.61 per cent in low-altitude oils to 53.09 per cent in those from higher elevations. At the same time, various species of polyunsaturated triglycerides show a significant decrease as altitude increases.
The fact that these patterns are consistent across both fatty acids and triglycerides reinforces the hypothesis that altitude leaves a distinct chemical signature in the oil, which can be used as supplementary information to characterise its origin.
Chemometrics to advance geographical authentication
One of the distinctive features of the study is the combined use of analytical techniques and chemometric tools to determine the extent to which lipid profiles can be used to distinguish oils according to their altitude of origin.
Linear discriminant analysis (LDA) applied to the 21 different altitudes achieved a classification accuracy of 96 per cent on the sample set itself, correctly classifying 24 out of the 25 samples. The researchers point out, however, that this result should be interpreted as a proof of concept due to the small number of samples per class and the risk of overfitting.
For this reason, the study also develops a more practical model based on three altitude categories: low (450–600 metres), medium (601–850 metres) and high (851–1,045 metres).
In this case, ‘leave-one-cut’ cross-validation achieved an overall accuracy of 60 per cent. High-altitude oils showed the best classification performance, with 83.3 per cent recall, due to the greater differentiation in their chemical profile, characterised mainly by higher levels of oleic acid and triolein and lower levels of palmitoleic acid.
The authors consider that these results constitute a proof of concept for the future development of lipid fingerprinting systems aimed at authenticating mountain oils, although they point out the need to expand the databases, incorporate different growing seasons and combine these markers with other families of compounds to improve predictive power.
New tools to promote mountain oils
The results obtained have potential applications in areas such as the authentication of geographical origin, traceability and the differentiation of mountain olive oils.
The identification of systematic relationships between altitude and lipid composition may contribute to the development of analytical protocols designed to verify claims of origin, detect possible labelling fraud and support certification processes for products linked to specific geographical areas.
Furthermore, the researchers suggest that this knowledge may contribute to the commercial enhancement of oils from mountain areas and provide valuable information for agronomic decision-making and for future breeding programmes tailored to specific growing conditions.
Multidisciplinary research serving the olive oil sector
In short, this publication highlights the value of integrating chemical analysis, knowledge of the production system and advanced statistical tools to address issues relating to the authenticity and quality of olive oil. This research was carried out within the framework of the MOUNTOLIVE I Operational Group ‘Differentiation and Valorisation of Mountain Olive Oil ’, attached to the University Institute of Research on Olive Grove and Olive Oils (INUO) at the University of Jaén, funded by the European Agricultural Fund for Rural Development (EAFRD) and co-funded by the Regional Government of Andalusia within the European Innovation Partnership for Agricultural Productivity and Sustainability (EIP-AGRI).
Article reference:
Beltrán, G., Gila, A., Sánchez, A., Jiménez, A., Sánchez-Quesada, C., Gaforio, J. J., & Aguilera, M. P. (2026). Altitude-driven variations in the lipid profile of extra virgin olive oil: A chemometric approach for geographical authentication. Agriculture, 16(17), 1851. https://doi.org/10.3390/agriculture16171851
