Usefulness of phenolic profile in the classification of extra virgin olive oils from autochthonous and introduced cultivars in Tunisia

The aim of this work was to characterize extra virgin olive oils (EVOOs) from four cultivars (Arbequina, Chetoui, Neb Jmal and Picholine) cultivated in Northern Tunisia (Borj El Amri) in terms of their phenolic profile. Determination of total phenol content was first performed spectrophotometrically using the Folin–Ciocalteu reagent. The total phenol content of the analyzed EVOOs varied from 77.33 mg GAE kg−1 in ‘Arbequina’ oil to 405 mg GAE kg−1 in ‘Picholine’ oil. Moreover, the polar extracts were analyzed by a rapid and effective Rapid-resolution liquid chromatography coupled to electrospray ionization time-of-flight mass spectrometry (RRLC–ESI-TOF/MS) method, and 48 phenolic compounds belonging to different classes were identified. The results showed significantly quantitative differences observed for all phenolic compounds except for oleuropein that was present only in two cultivars. In all olive oil samples studied, secoiridoids were the most abundant. Deacetoxyoleuropeinaglycone remains the most abundant complex phenol in Picholine (250.39 mg kg−1), Neb Jmal (104.34 mg kg−1) and Arbequina (19.93 mg kg−1) EVOOs, while in Chetoui oil, the oleuropeinaglycone isomer 5 content is the highest with mean value of 381.63 mg kg−1. The application of principal component analysis permitted a good classification of the EVOOs according to their phenolic profiles.