Influence of olive ripeness on chemical properties and phenolic composition of Chemlal extra-virgin olive oil

This work examines the olive-oil quality and chemical characterization of the main compounds from extra-virgin olive oil (EVOO) extracted from Chemlal olive cultivar, corresponding to different olive-harvest dates in the north-central region of Algeria. For a complete description of olive-oil samples, olive-oil yield, quality indices, fatty acid composition, oxidative stability, pigments, tocopherols, and individual polar phenolic compounds were evaluated. This is the first report available in which polyphenols of Chemlal EVOO variety have been characterized by rapid-resolution liquid chromatography coupled to electrospray time-of-flight mass spectrometry. The results show variations in chemical composition of Chemlal EVOOs obtained at different olive-ripening stages. Quality parameters tended to increase and the highest values were found in EVOOs from late harvest dates. In addition, the harvest date had a significant effect on the maturity index, oxidative-stability, chlorophyll and phenolic composition. However, olive-oil yield, carotenoids, and tocopherol content showed no significant variation. According to the results based in the ripening process, the maturation index 2.4 appears to be the most appropriate harvest moment to collect olives in order to obtain Chemlal EVOOs of high chemical quality. © 2013 Elsevier Ltd.