Correlation between thermal properties and chemical composition of Italian virgin olive oils

Thirteen monovarietal extra virgin olive oils (EVOos) from two Italian regions were evaluated by means of differential scanning calorimetry (DSC) to study statistical correlations among major and minor chemical components and thermal properties obtained by cooling transitions and their deconvoluted peaks. The application of DSC for the discrimination of EVOos according to the cultivar and geographical origin, was also considered. Thermal properties of the cooling transitions (except for the crystallization enthalpy) were almost all influenced by triolein content and fatty acid composition. Thermal properties (area, onset and offset temperatures of transition, transition range and peak temperature) of the three deconvoluted peaks were found to be significantly correlated not only to major but also to minor components (diacylglycerols, free fatty acids) and oxidative stability indices. The analysis of thermal properties obtained by cooling transition did not lead to sample discrimination according to geographical provenience. However, Ton, Toff and peak areas of the two deconvoluted transitions that peaked at the lowest temperatures, as well as Toff of deconvoluted peak at the highest temperature, significantly differentiated oil samples according to their geographical origin. These findings may be confirmed by the appliance of multivariate statistical analysis to a larger set of samples to select thermal parameters able to discriminate among EVOos of different geographical provenience.