Study of the oxidative stability of Tunisian extra virgin olive oil in the course of its storage

Tunisian extra virgin olive oil (EVOO) of Chetoui variety oxidation intensity depends on intrinsic composition, model packing and storage conditions. Thus, external factors such as kind of packing (glass, terephtalate polyethylene (PET), metal), full or attenuated day light, obscurity, air on bottles headspace, presence of metallic trace (iron and copper) and filtration influence on EVOO oxidative stability during two years storage at ambient temperature was studied. Peroxide value and ultraviolet specific extinction at 232 and 270 nm (K232 and K270) of oil bottled in PET and stored at obscurity for two years are significantly then the highest. On the other hand, oil bottled in glass bottles has shown the best physicochemical and organoleptic characteristics and also phenol and alpha-tocopherol contents were few higher than those of oil bottled into metal or PET packing. Oil exposure to light at storage increases quickly their photooxidation depending on EVOO chlorophylls levels. However, neither packing with nitrogen headspace nor filtration affects significantly oil stability.