NUTRITIONAL AND BIOACTIVE COMPOUNDS FROM AGRI-FOOD PRODUCTS AND BY-PRODUCTS: IN VITRO ASSESSMENT OF THEIR POTENTIAL HEALTH EFFECTS

The growing need to reduce the environmental footprint of human activities and to ensure sustainable food production has accelerated the transition toward more resource-efficient and nutritionally balanced food systems. At the same time, increasing consumer interest in healthpromoting and naturally derived ingredients is driving innovation in the functional food and nutraceutical sectors. Within this context, the valorisation of underutilized crops and agri-food by-products represents a promising strategy to enhance food system sustainability while expanding the range of available bioactive ingredients. This research was based on the hypothesis that selected plant resources and agri-food byproducts, when subjected to optimized, environmentally friendly extraction and processing methods, can yield bioactive compounds with significant nutritional and health-promoting potential, while also contributing to circular bioeconomy models. To test this hypothesis, the study pursued two main objectives. The first was to characterize the nutritional and bioactive profiles of selected plant cultivars with the dual aim of identifying climate-resilient varieties and assessing their potential contribution to sustainable, nutrient-rich diets. The second objective focused on the valorisation of agri-food by-products through the development and optimization of selective, “green” extraction methods designed to recover functional molecules—such as polyphenols, peptides, and dietary fibres—while mitigating matrix effects that limit extraction efficiency, purity, and bioavailability. The results demonstrated substantial variability in the nutritional composition and bioactive compound content among the studied cultivars, highlighting specific landraces well-suited to cultivation in resource-limited environments. Optimized extraction processes significantly improved the recovery yields and stability of target compounds from by-products compared with conventional methods, confirming the effectiveness of tailored green technologies. In vitro gastrointestinal digestion models indicated good stability and bioaccessibility of several bioactive fractions, while cell-based assays using Caco-2 human intestinal epithelial cells revealed low cytotoxicity and, in selected cases, modulatory effects on oxidative stress and inflammatory responses. By integrating the valorisation of plant biodiversity with the recovery of bioactive compounds from agricultural by-products, this thesis provides scientific evidence supporting the development of sustainable, circular, and health-oriented food systems. Furthermore, it demonstrates the potential of combining crop science, food chemistry, and cellular biology approaches to generate functional ingredients that align with global sustainability goals and the growing demand for nutritionally beneficial food products.