Phenolics fate in table olives (Olea europaea L. cv. Nocellara del Belice) debittered using the Spanish and Castelvetrano methods

The removal of the bitter taste from raw olives depends on the hydrolysis of oleuropein, a process that requires a couple of weeks to several months, according to the technology adopted. A deep analysis of individual phenolic compounds (19 molecules) in olive drupes (Olea europaea, cv. Nocellara del Belice) debittered using the Spanish and the Castelvetrano methods is reported, taking into account the entire debittering process (seven sampling times throughout 7 months). The study demonstrates that the two approaches yield quantitatively and qualitatively similar phenols, even if through different intermediates and catabolic pathways. Moreover, the results indicate that the commercially profitable practice of storing Castelvetrano olives in the fermentation brine over the necessary fermentation time, can potentially determine the degradation olives of greater amounts of several healthy metabolites of oleuropein like hydroxytyrosol, oleoside, oleoside 11-methyl ester and glucosyl methyl oleoside.