Quantitation of Oleuropein and Related Phenolics in Cured Spanish-Style Green, California-Style Black Ripe, and Greek-Style Natural Fermentation Olives.

Oleuropein, ligstroside, and related hydrolysis products are key contributors to olive bitterness, and several of these phenolics are implicated in the prevention of lifestyle age-related diseases. While table olive processing methods are designed to reduce oleuropein, the impact of processing on ligstroside and related hydrolysis products (e.g., oleacein, oleocanthal, hydroxytyrosol glucoside, ligstroside aglycone, and oleuropein aglycone) is relatively unknown. Herein, levels of these compounds were measured in Spanish-style green (SP), Californian-style black ripe (CA), and Greek-style natural fermentation (GK) olives using rapid ultrahigh-performance liquid chromatography (UHPLC) tandem mass spectrometry (MS/MS). GK olives had the highest concentration of all compounds measured, with the exception of oleocanthal, which was highest in SP olives (0.081 mg kg-1 wet weight (w.wt)). CA olives had the lowest levels of most compounds measured, including ligstroside (0.115 mg kg-1 w.wt) and oleuropein (0.974 mg kg-1 w.wt). Hydroxytyrosol was the predominate compound in all three styles of commercial olives, with similar concentrations observed for GK and SP olives (134.329 and 133.685 mg kg-1 w.wt, respectively) and significantly lower concentrations observed for CA olives (19.981 mg kg-1 w.wt).