Variability of vitamin E in virgin olive oil by agronomical and genetic factors

In this work the effect of genetic and agronomic factors on virgin olive oil tocopherol content and composition has been studied. For genetic effect, olive oil from thirty olive cultivars has been analyzed; for agronomic factor evaluation, three olive cultivars have been monitored during fruit ripening for three consecutive crop years. Total tocopherol content has ranged between 84 and 463 mg/kg, α-tocopherol represented more than 95%, β-tocopherol was found at very low concentrations whereas γ-tocopherol varied from 1 to 29 mg/kg. Tocopherols in virgin olive oil have a significant genetic component. Variability by crop year was due to the rainfall levels, and oils from the drier crop year (1998/99) showed the highest tocopherol content. However, this effect was cultivar-dependent, with ‘Hojiblanca’ cultivar the most affected. In general, tocopherols decreased during the ripening process, and although γ-tocopherol showed an increase for the last harvesting dates, this trend was related to the chlorophyll losses in the oil.