High-performance liquid chromatography evaluation of phenols in olive fruit, virgin olive oil, vegetation waters, and pomace and 1D-and 2D-nuclear magnetic resonance characterization

Phenolic compounds are the most important antioxidants of virgin olive oil. This paper reports on the application of solid phase extraction (SPE) in t he separation of phenolic compounds from olive fruit, olive oil, and by-pro ducts of the mechanical extraction of the oil and the complete spectroscopi c characterization by nuclear magnetic resonance of demethyloleuropein and verbascoside extracted from olive fruit. SPE led to a higher recovery of ph enolic compounds from olives than did liquid/liquid extraction. SPE also wa s used to separate phenolic compounds from pomaces and vegetation waters. P henyl-acid and phenyl-alcohol concentrations in extracts obtained from SPE and liquid/liquid extraction were not significantly different (P < 0.05). T he recovery of the dialdehydic form of elenolic acid linked to 3,4-(dihydro xyphenyl)ethanol and an isomer of oleuropein aglycon, however, was low.