Valutazione di composti bioattivi ad attività antiossidante in alimenti di origine vegetale

In plant-derived products there are naturally some bioactive compounds, that is substance with or without nutritional value, having biological activity in prevention of the developing of several chronic diseases, so protecting human health. In this group there are antioxidants, molecules that, when present at low concentrations compared with those of an oxidizable substrate and under specific assay conditions, can delay or prevent oxidation of that substrate. The importance of antioxidants in foods is connected both to the protection of the shelf-life of food, delaying polyunsaturated fatty acids oxidation, and to delaying in vivo, in human body, of chronic-degenerative diseases caused by oxidative stress and age. Mainly antioxidants include vitamins, polyphenols, carotenoids, such as lutein, and minerals; whose content in plant foods can be influenced by several factors such as variety, pedoclimatic conditions and technological processes. In the light of this considerations, the research activity of PhD is aimed at the evaluation of bioactive compounds, in particular antioxidants, in plant-derived products, both cereals and fruits and vegetables, developing in three sections: - evaluation of lutein content of different fruits and vegetables and of forms in which it can be present in foods, like free, esterified with fatty acids and bound to matrix by using of an extraction method characterized by saponification followed by extraction with solvents and HPLC analysis, particular attention has been focused on bound lutein not extimated in literature. The obtained results confirm the needing to carry out a saponification step of vegetables matrix followed by extraction with solvents, in order to obtain the amount of lutein bound to matrix, which represents a considerable part of total lutein content; - evaluation of polyphenol content and related antioxidant capacity of differently treated fruits and vegetables sampled in two different hospital canteens at different seasons. The obtained results demostrated that fruits and vegetables, even deep-frozen and not fresh, provide a good contribution of polyphenols and positively contribute in recovering of hospitalized subjects; - development of unique, valid and reliable extraction method of both lipid-soluble (carotenoids and tocols) and water-soluble antioxidants (free and bound polyphenols), able to extract at the same time both fractions (lipid-soluble and water-soluble) of cereals like durum wheat, considering that the literature methods separately extract these two fractions. The developed method allowed the extraction of both components of cereals, without showing significant differences in the extraction capacity as to literature methods.