Phenolic Compounds Characterization and Antioxidant Properties of Monocultivar Olive Oils from Northeast Algeria

Abstract: In Algeria, the olive tree is one of the main fruit species and plays a very importantsocioeconomic role. The objective of this study was firstly, to identify and quantify the phenolics ofsome Algerian olive oils, and secondly, to assess the antioxidant activity of the samples. The olive oilsused in this study were derived from Algerian cultivars, including Tefahi, Gelb Elfarroudj, Chemlal,and imported cultivar Manzanilla and Zebboudj. For this purpose, gas chromatography--massspectrometry (GC-MS) was used to identify olive oil fatty acids profile, while the individualphenolic compounds were assessed by ultra-high-performance liquid chromatography-electrosprayionization-high-resolution mass spectrometry (UHPLC-HESI-MS). To verify the antioxidant capacity,five in vitro free radical assays were used. Questionable values of particular physico-chemicalparameters, such as the high value of free acidity and the low concentration of monounsaturatedfatty acids in oil from the Zebboudj cultivar, indicate that improvements in olive cultivation and oilproduction practices are needed. Gelb Elfarroudj, Tefahi, and Manzanilla oils contain quantities ofmonounsaturated fatty acids in accordance with EU regulations. The oil obtained from the Zebboudjcultivar is not usable for food purposes due to the high value in free acidity and the low concentrationof monounsaturated fatty acids. Tefahi and Manzanilla cultivars have given oils with the bestantioxidant activity as compared to other studied cultivars; this is attributable to their composition inbioactive phenolic compounds, such as secoiridoids, which play an important role in human healthas scavengers of free radicals. The results are interesting for producers and consumers to promote theculture of olive oils derived in particular from the Tefahi cultivar. However, in order to improve thehealth qualities of this oil, the agronomic techniques essentially linked to the time of harvesting of theolives destined for oil production must be improved.