Grasas y Aceites, Vol 68, No 1 (2017)

An explanation for the natural de-bittering of Hurma olives during ripening on the tree

E. Susamci
Olive Research Institute, Üniversite Caddesi, Turkey

C. Romero
Instituto de la Grasa (IG-CSIC), Spain

O. Tuncay
Faculty of Agriculture, Ege University, Turkey

M. Brenes
Instituto de la Grasa (IG-CSIC), Campus University Pablo de Olavide,, Spain


Harvested olives require further processing to make them edible due to their content in the bitter substance oleuropein. However, some olives of the Erkence cultivar naturally de-bitter on the tree giving rise to the so-called Hurma olives. In this study, the evolution of the chemical characteristics of Erkence and Hurma olives harvested from the northeast and southwest area of trees located in the Karaburun Peninsula was assayed. It was confirmed that the oleuropein content in Hurma olives was much lower (< 2000 mg/kg fresh weight) than Erkence, which reached 35.000 mg/kg fresh weight at the beginning of the season. In addition, no free or polymerized anthocyanins were found in Hurma fruit in contrast to ripened Erkence fruit. The concentration of glucose was also lower in Hurma than Erkence olives. These results suggest that the enzymatic oxidation of oleuropein could be responsible for the natural de-bittering of Hurma olives during their ripening on the tree.


Anthocyanin; Bitterness; Olive; Phenolic compounds; Sugar

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