Transfer of phenolic compounds during olive oil extraction in relation to ripening stage of the fruit

The transfer of phenolic compounds of Olea europaea L. cv. Arbequina variety during olive oil extraction in relation to ripening stage was investigated. The parameters of oil extraction by the Abencor system are shown together with mass balances of the products and by products from the olive oil extraction in relation to olive paste. The phenolic compounds in olive paste, pomace, oil and wastewater were identified and measured by HPLC. Throughout the study, the concentrations of simple phenols, secoiridoids and flavonoids were higher in the olive paste and pomace phases than in oil and wastewater phases. High concentrations of 4-(acetoxyethyl)-1,2-dihydroxybenzene (3,4-DHPEA-AC) and secoiridoid derivatives such as the dialdehydic form of elenolic acid linked to 3,4-DHPEA (hydroxytyrosol) or p-HPEA (tyrosol) (3,4-DHPEA-EDA, p-HPEA-EDA, where EDA is elenolic acid dialdehyde) and an isomer of oleuropein aglycone (3,4-DHPEA-EA, where EA is elenolic acid aldehyde) were found in olive oil, together with lignan compounds. It was observed that 3,4-DHPEA-EDA was the most abundant polyphenol. present in the wastewater phase. This indicates that biotransformation occurred during olive extraction, especially in the crushing and malaxation operations, and reflects the possible chemical changes that lead to the formation of new compounds. Moreover, the distribution of compounds showed their affinities toward different phases. (c) 2005 Society of Chemical Industry.