Different spectroscopies for the evaluation of the quality of olives and olive oil

The research group LPF-TAGRALIA has developed diverse studies using spectroscopic technologies applied to non-destructive determination of the quality of olive fruits and olive oil. NIR spectroscopy was applied to the determination of the oil content in fresh olives and in dehydrated olives. High resolution nuclear magnetic resonance spectroscopy was applied to the study of the evolution of major and minor compounds in extra virgin olive oil. Fluorescence spectroscopy of high resolution in excitation /emission, in 'front-face' set-up, was applied to the study of different qualities of olive oils. Multivariate analysis was applied to the spectra and models were developed for differentiated levels of oxidation and freshness in the oils. LPF-TAGRALIA designed a prototype that allows in a much simpler and rapid way to acquire the fluorescence signal from chlorophyll and products of oxidation, as well as of polyphenols and alpha- tocoferol, with simultaneous excitation with a wide band of wavelengths. The studies with this prototype allowed to monitor the evolution of the chlorophyll and of the compounds related to the processes of oxidation and have established differences in the rate of aging between different oils varieties and between different conditions of storage.