State-of-the-art and trends in the analysis of oleuropein and derivatives

We give an on overview of the state-of-the-art in the steps involved in analyzing oleuropein and its derivatives (also known as biophenols or BPs) from different olive sources.Sampling and sample preparation (SP) strongly depend on the matrix from which these compounds are removed. Sampling is highly dependent on the physical state of the material under study and SP ranges greatly from simple dilution (e.g., olive oil) to complex treatment involving steps such as leaching, filtration, centrifugation, drying, reconstitution, and solid-phase extraction.After preparation, the solution obtained is ready for the determination step, which can comprise overall measurement of BPs by the Folin-Ciocalteu method or individual quantification after chromatographic or electrophoretic separation. The determination step is well established; in most cases, SP is performed by conventional, time-consuming procedures.In view of the growing importance of BPs, we call for the development of new methods based on updated techniques, which could be transferred to industry for proper mass production of these compounds that are of great interest from the points of view of food, medicine and cosmetics.