Quality Evolution of Extra Virgin Olive Oils of 'Chemlal' Cultivar during Storage at Environment Temperature: Effect of the Altitude and Age of Olive Trees

This work aimed to study the influence of two factors on oil composition: the altitude of olive groves and the age of olive trees, as well as the duration olive oil was stored in the dark and at room temperature. Firstly, quality parameters (free acidity, peroxide value, K232 and K270), minor compounds (pigments, total phenolic compounds, tocopherol fraction and fatty acid profile) and oxidative stability measured at 98.0 degrees C (by Rancimat) made it possible to evaluate the quality of the samples during one year of storage. A significant difference was reported in pigment contents as a function of altitude. In particular, several changes were observed during storage, which led on the one hand to a continuous increase in free acidity, peroxide value, K232, K270 and on the other hand a degradation of natural antioxidants such as phenolic compounds, pigments and tocopherols and consequently to oxidation stability. However, the modification of the fatty acid composition was small and did not show any major changes.