DSC EVALUATION OF OLIVE OIL DURING ACCELERATED OXIDATION

Changes in differential scanning calorimetry cooling thermal properties of an extra virgin olive oil in the presence and absence of its phenolic fraction were evaluated at different times of accelerated storage treatment (up to 4 weeks at 60°C under air) and related to lipid oxidation molecules (measured with k232 and k270 indices) and total phenol content. Phenols did not appear to directly influence crystallization of extra virgin olive oil as neither cooling profiles nor thermal properties differed significantly between the two oils at the beginning of storage. However, oil samples deprived of phenols showed more significant changes at the longest storage time in comparison with untreated oil. Cooling transitions were all deconvoluted into three peaks. Changes in thermal properties were more evident for the two transition peaks at the highest temperature in both oil samples. Thus, a marked influence of lipid oxidation products on the crystallization pattern of these two peaks may be hypothesized.