Effect of the soil nature on selected chemico-physical and thermal parameters of extra virgin olive oils from cv Chemlali

The current study assessed the effect of different soils (clay, EVOOsC, stony, EVOOsS, brown, EVOOsB, limestone and gypsum, EVOOsLG) on the chemico-physical (free acidity, peroxide value, oxidative stability, fatty acids, pigments, colour, viscosity, heat capacity) and thermal (upon DSC) quality of four 'Chemlali' extra virgin olive oils. EVOOsC showed the lowest peroxide value, the highest amount of monounsaturated fatty acids and the narrowest crystallization range. EVOOsLG had the highest content of saturated and polyunsaturated fatty acids as well as the lowest stability to oxidation and melting enthalpy. EVOOsS and EVOOsB revealed the highest viscosity, while the heat capacity measurement didn’t show any difference among the oils. EVOOsB exhibited the highest b* colour parameter in relation to the highest carotenoids content. These preliminary findings have showed that the nature of the soil has an effect on the final quality of EVOO, as also revealed by the PCA analysis.