Fluorescence Study of Four Olive Varieties Paste According to Sampling Dates and the Control in the Elaboration of Table Olives of “Ascolana tenera”

A fluorescence method combined with chemometric algorithms has been developed for the fruit characterization of four olive varieties (“Arbequina,” “Piantone di Falerone,” “Piantone di Mogliano,” and “Maurino”) cultivated in Marche (Italy) according to sampling dates. The score values obtained by parallel factor analysis (PARAFAC) were correlated with the hydroxytyrosol and oleuropein concentrations quantified by liquid chromatographic. The analysis of excitation-emission matrices by PARAFAC and unfolding partial least squares, using the three component score values, allowed to differentiate between varieties. The use of the scores of oleuropein and hydroxytyrosol, which were represented each other, allowed to highlight differences between the three sampling dates. Furthermore, a good discrimination of fresh olive, lye table olives, and natural table olives was also achieved in “Ascolana tenera,” another typical olive variety of Marche. Results can be explained by the changes of concentration of tyrosol and oleuropein due to the elaboration method characteristics.