Polyphenols fingerprinting in olive oils through maximum-quantum NMR spectroscopy

An NMR protocol based on multiple-quantum spectroscopy is presented for an analytical screening of polyphenols in olive oils. Three Italian olive oils with different total polyphenols content were used as study case. A total of 24 compounds were identified as follows: 1 polyphenol in the 5Q–1Q, 15 more in the 4Q–1Q, and 8 components in the 3Q–1Q spectra, consisting of organic phenols, secoiridoids, lignans, and flavonols. In the three Italian olive oils investigated here, the polyphenols profile turned out to be significantly different, with specific characteristics going beyond simple considerations based on the total polyphenol content. The approach presented here can be easily extended for rapid qualitative and semi-quantitative screening of the polyphenol composition in many food products.