Genotypic Variation of Total Phenol and Oleuropein Concentration and Antioxidant Activity of 11 Greek Olive Cultivars (Olea europaea L.)

The chemical and biochemical composition of olives relies on some agronomical factors, one of which is the cultivar. In this study, fruits and leaves of 11 Greek olive cultivars were examined concerning their phenol and oleuropein concentrations. Fruit antioxidant activity was determined as well. The obtained results showed that significant differences existed among cultivars regardless of the tissue or the measured parameter. In general, leaves had higher total phenol and oleuropein concentrations than fruits. Finally, the highest oleuropein concentration in fruits was recorded in 'Pikrolia Kerkiras' followed by 'Romeiki', 'Megaritiki', 'Kothreiki', and 'Kalamon'. These cultivars may constitute the raw material in the industrial production of oleuropein. Experimental olive orchard. The study was carried out in a field planted with 11 Greek olive cultivars, namely 'Kalamon', 'Kothreiki', 'Maronia', 'Megaritiki', 'Petrolia', 'Pikrolia Kerkiras', 'Romeiki', 'Smertolia', 'Thassitiki', 'Throubolia Aegean', and 'Valanolia' (seven trees per cultivar and of the same age and vegetative habits), during the 2009-2010 sea- son. These 10-year-old olive cultivars were grown in the same orchard located in Poros Troizinia, Northeast Peloponnese, Greece (lat. 37� 31# N, long. 23� 29# E). The climate of the area is Mediterranean with mild winters (9-10 � C) and dry, hot summers (27-28 � C). The mean annual precipitation of the area is 550 mm. The olive plants were subjected to the same cultural conditions (pruning, fertil- ization, irrigation, and harvesting). For each cultivar, a 3-kg composite sample of fruits and 1 kg of current-season leaves were collected from all the orientations of the tree canopy on 15 Nov. Each composite sample (fruit or leaf) was divided into three subsamples of 200 g each. Maturity index. The maturity index of