Changes in phenolic and enzymatic activities content during fruit ripening in two Italian cultivars of Olea europaea L.

During the ripening of two Italian cultivars of Olea europaea L. (Ascolana Tenera and Frantoio Seedling no. 17 (FS17)) we have identified a P-glucosidase activity that contributes to the oleuropein degradation during maturation as well as an esterase activity, whose trend during the ripening is hypothesised to be linked to the fatty acid biosynthesis involved later in the maturation of fruits. This activity, in fact, is involved in the estereolysis of C-3 and C-4 esters that supply acetyl-CoA as the basic unit for fatty acid biosynthesis. The data obtained during the ripening indicate that polyphenol content and composition, in particular the oleuropein concentration, and their correlation with the recovered enzymatic activities, will be useful for a biochemical characterisation of different O. europaea L. varieties as important parameters in testing the quality of the obtainable oils. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.