Isolation and identification of minor secoiridoids and phenolic components from thermally treated olive oil by-products.

The application of an industrial process based on the hydrothermal treatment of 160 °C/60 min of alperujo, a by-product of olive oil extraction, allows the formation of a liquid phase containing a high concentration of phenolic and secoiridoid compounds. Ethyl acetate was used to extract these phenolic compounds from the aqueous matrix. In this study, the isolation with polyamide and XAD resin allowed detection of the presence of phenolic compounds in minor concentrations. These minor phenols were several oleuropein derivatives that had not been identified in these phenolic extracts previously. The polar compounds, acteosides, secoiridoids, and flavonoids, that remain in the aqueous fraction after extraction with ethyl acetate were identified. We report the presence of known compounds and also detected a novel molecule in alperujo with a molecular weight of 408 whose structure was characterized for first time. This new secoiridoid glucoside was identified as 1-β-D-glucopyranosyl acyclodihydroelenolic acid.