Exploring the quality and nutritional profiles of monovarietal oils from millennial olive trees in Tunisia

In Tunisia, the olive tree has been cultivated for more than 3000 years by different civilizations, such as the Phoenicians, Greeks, Carthaginians, Romans, and Arabs. The ancient olive trees, which thrive in harsh environments, are little known and contain a foremost part of the olive germplasm. This study focused on the chemical oil analysis of the Tunisian millennial olive trees dating from the Roman and the Carthaginians periods. Twenty-eight antique olive trees grown in Tunisia's north to south are the subject of this study. Analyzed according to international standards, the tested accessions present oil with high quality, rich in chlorophyll and carotenes, and highly rich in polyphenols. The oil's fatty acid composition is complete with the international norms with a high oleic acid content, low palmitic and linoleic acid concentrations, and a C18:1/C18:2 ratio ≥ 7. Four oils, in particular, contained substantial levels of polyphenols (500–1632 mg/kg) and a C18:1/C18:2 ratio of > 9. Subsequently, it is crucial to prevent the extinction of ancient olive trees to preserve their historical significance and ecological worth, as well as to incorporate the best genotypes into new varieties and boost the competitiveness of Tunisian olive oil on the global market.