The potential of wild olive leaves (Olea europaea L. subsp. oleaster) addition as a functional additive in olive oil production: the effects on bioactive and nutraceutical compounds using LC-ESI-QTOF/MS

This study aims to investigate the influence of traditional maceration upon the enrichment of olive oil with oleaster leaves. The phenolic and tocopherolic compositions of control olive oil and enriched olive oils were determined. The influence of these oil preparation procedures on oil quality indicators was also investigated through spectrophotometric indices and fatty acid profiles. The total contents of bioactive compounds and pigments improved in oils obtained by maceration of fresh wild olive leaves, and were in statistically significant correlation with leaves proportions additions. The obtained results revealed that 15 phenolic compounds belonging to different phenolic types were characterized and quantified by an effective HPLC-DAD-ESI-MS/MS method. In all expected olive oils, the oleuropein aglycon (3,4-DHPEA-EA), and ligstroside aglycon (p-HPEAEA) derivatives were the most abundant compounds. Similarly, to phenolic compounds, tocopherols strongly increased with leaves addition during maceration process. The data obtained from this study suggested that the addition of olive leaf to oils allowed more functional olive oils with higher antioxidant contents. Thus, Extra Virgin Olive Oil (EVOO) extracted with 10% of olive leaves presented the highest amount of phenolic and tocopherol compounds.

Automated summary

This study investigated the enrichment of olive oil with oleaster leaves using traditional maceration. The composition of phenolic and tocopherol compounds in the oils was determined, and the effects of the maceration process on oil quality indicators were investigated. The results showed that the addition of fresh wild olive leaves during maceration improved the total contents of bioactive compounds and pigments in the oils. Several phenolic compounds were characterized and quantified using an effective HPLC-DAD-ESI-MS/MS method. The most abundant compounds were derivatives of oleuropein aglycon and ligstroside aglycon. Tocopherols also increased significantly with the addition of leaves. Overall, this study suggests that the addition of olive leaf during the maceration process can result in functional olive oils with higher antioxidant contents.