Water Deficit during Pit Hardening Enhances Phytoprostanes Content, a Plant Biomarker of Oxidative Stress, in Extra Virgin Olive Oil

No previous information exists on the effects of water deficit on the phytoprostanes (PhytoPs) content in extra virgin olive oil from fruits of mature olive (Olea europaea L. cv. Cornicabra) trees during pit hardening. PhytoPs profile in extra virgin olive oil was characterized by the presence of 9-F1t-PhytoP, 9-epi-9-F1t-PhytoP, 9-epi-9-D1t-PhytoP, 9-D1t-PhytoP, 16-B1-PhytoP + ent-16-B1-PhytoP, and 9-L1-PhytoP + ent-9-L1-PhytoP. The qualitative and quantitative differences in PhytoPs content with respect to those reported by other authors indicate a decisive effect of cultivar, oil extraction technology, and/or storage conditions prone to autoxidation. The pit hardening period was critical for extra virgin olive oil composition because water deficit enhanced the PhytoPs content, with the concomitant potential beneficial aspects on human health. From a physiological and agronomical point of view, 9-F1t-PhytoP, 9-epi-9-F1t-PhytoP, and 16-B1-PhytoP + ent-16-B1-PhytoP could be considered as early candidate biomarkers of water stress in olive tree.