The evolution of free acidity and oxidation related parameters in olive oil during olive ripening from cultivars grown in the region of Calabria, South Italy

Abstract

The variation in free acidity and oxidation related parameters was studied in olive oil produced from olives at different stages of ripening from cultivars growing in the Calabria region (South Italy). A three-year study was conducted on twelve cultivars growing in rainfed conditions. The number of bi-weekly samplings per each cultivar varied from 5 to 7 depending on the cultivar characteristics in this geographical area. Free acidity remained within the present legal parameters for an extra virgin olive oil (< 0.8%) in all cultivars until 1st November and was highest in Nocellara Messinese cv (1.23%) and in Sinopolese cv (1.25%) on 3rd January. Phenolic and tocopherol contents were highest in oils from Nociara cv (350 mg kg -1 and 223 mg kg-1 respectively) and in Coratina cv (342 mg kg -1 and 216 mg kg-1 respectively) on 1st October and decreased constantly during olive ripening. Oil stability index was maximum in Itrana cv, from 22.48 h to 8.82 h in two months ripening. Chlorophyll and carotene content decreased with harvest date.