The stability of extra virgin olive oils is mainly due to their relatively low fatty acids unsaturation and to the antioxidant activity of some of the unsaponifiable components. We studied the activity of alpha-tocopherol in extra virgin olive oil in its natural state, using new and simple oxidizing conditions in "thin layer" and "bulk phase". Oxidation time course was monitored at 37 degrees C or 75 degrees C. A storage test was also performed. Two parameters were evaluated: depletion of alpha-tocopherol and formation of PUFA hydroperoxides, measured as conjugated dienes (CD) and peroxide value. The value of complex polyphenols was also measured. alpha-Tocopherol concentration decreased in function of time and temperature and showed a strong inverse correlation with the increase of CD. When alpha-tocopherol reached a "threshold value" of 60-70 mg/kg, a significant increase of CD formation was observed, together with a good correlation between CD and peroxide value. The initial amount of alpha-tocopherol is one of the components that influences oil oxidative susceptibility.

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The chemical composition affects the sensory properties and quality of Extra Virgin Olive Oil (EVOO). In addition, its knowledge can supply valuable information about the cultivar and its geographical origin. The goal of this study is to obtain a protocol in order to be able to recognize the composition of various Sardinian oils and to consequently correlate them with their production areas. High‐resolution 1H NMR spectroscopy was used to analyze 100 (82 training + 18 test sets) samples of EVOO from the Bosana cultivar, collected from different growing areas in Sardinia (Italy). Growth areas were classified on the basis of FAO‐UNEP aridity index. NMR data were processed with multivariate statistical analysis. NMR profiling presents a connection between environmental factors of Sardinian cultivation areas and the chemical composition of EVOO. An NMR‐based metabolomic approach that uses six “one‐to‐one” OPLS‐DA models allowed us to discriminate the different influence of evapotranspiration, solar exposure, and altitude on the chemical composition of Bosana EVOO. Practical Applications: Detailed knowledge of NMR spectra pattern variations could have a potential impact on olive oil market. The application of the 1H NMR metabolomic, based on chemometric models, can be a useful tool in order to certificate the geographical origin of EVOO. An NMR‐based metabolomic approach,using “one‐to‐one” OPLS‐DA models, allows to identify biomarkers of different production zones in “Bosana” Sardinian EVOO.