Advanced chromatographic techniques coupled to mass spectrometry for the analysis of matrices of nutritional and nutraceutical interest

The research work described in this PhD thesis was mainly focused on the development of analytical methods based on chromatography coupled to mass spectrometry (MS), for the analysis of matrices containing molecules of nutritional and nutraceutical interest, with particular emphasis on lipids, peptides and polyphenols. Most of the scientific efforts were put into developing multitechnique analytical approaches for the retrieval and valorization of the protein and lipid fractions from the wastes of the fishery industry. Specifically, this research allowed the identification of valuable molecules in tuna by-products, such as omega-3 polyunsaturated fatty acids (ω-3 PUFA), e.g., docosahexaenoic acid (C22:6) and eicosapentaenoic acid (C20:5) and short- and medium-size tryptic peptides with potential antimicrobial activity. The characterized components will be conveniently combined in nutraceutical formulations, beneficial for human health. Additional research activities have been focused on the elucidation of the lipid profile of different plant oils and related products, with particular emphasis on glycerolipids in their native form. For such purposes, liquid chromatography (LC), comprehensive liquid chromatography (LCxLC) and subcritical solvent chromatography (subFC) approaches coupled to atmospherical pressure chemical ionization-MS (APCI-MS) have been exploited as powerful analytical strategies for the characterization of complex matrices. Furthermore, aiming at improving the identification process in LC, a recently introduced linear retention index (LRI) approach has been employed in combination to MS, to achieve a reliable identification of triacylglycerols (TAGs) components. The investigation of less conventional matrices allowed to improve the LRI laboratory-constructed database; in detail, a substantial contribution was provided by the analysis of marine organisms samples, i.e. tuna waste oil, highly rich in ω-3 PUFA-containing TAGs. Within the same study, matrices containing uncommon fatty acids and their positional isomers have been investigated, i.e. hemp seed oil, highly rich in ɣ- and α-linolenic acids. Finally, Hibiscus sabdariffa and Zingiber officinale extracts were characterized by LC coupled to photodiode array (PDA) and MS detection, and the availability of polyphenols at the colon level was evaluated for their potential applications in the treatment of intestinal ailments.