BIOACTIVE COMPOUNDS IN FERMENTED FOODS: ROLE IN THE ANTIOXIDANT AND ANTI-INFLAMMATORY PROCESS

This doctoral research explored the role of fermentation as a sustainable biotechnological process to enhance the nutritional, functional, and health-promoting properties of plant-based and algal food matrices. The overall goal was to understand how microbial fermentation can release and generate bioactive compounds with antioxidant and anti-inflammatory activity, contributing to the development of functional foods and preventive nutrition strategies. The thesis is organised into chapters that correspond to the scientific articles that were published during my doctoral research. The first chapter focused on Parkia biglobosa (African locust bean) seeds, traditionally fermented in West Africa and used for healthy food production. Fermentation with sourdough, significantly increased polyphenol content and in vitro antioxidant capacity, while both fermented and unfermented extracts exhibited protective and antihypertensive activities. These results support the nutraceutical potential of P. biglobosa as a valuable ingredient for functional food formulation. The second chapter examined the fermentation of the microalgae Chlorella vulgaris and Aphanizomenon flos-aquae with Saccharomyces cerevisiae and Lactiplantibacillus plantarum. Fermentation markedly improved microalgae antioxidant potential, particularly after 24 hours, emphasizing the importance of optimizing microbial strains and process conditions to enhance bioactivity. These findings identify fermented microalgae as promising natural sources for functional foods aimed at mitigating oxidative stress-related conditions. The third and fourth chapters of the research analysed whole-wheat flour fermented with selected lactic acid bacteria and yeast strains. Fermentation substantially increased the release of bound phenolic compounds and bioactive metabolites, enhancing both antioxidant and anti-inflammatory potential. In human intestinal cells (HT-29), fermented extracts upregulated antioxidant defence genes (CAT, HMOX-1) and downregulated NF-κB–dependent pro-inflammatory mediators (IL-6, IL-8, COX-2), suggesting a role for fermented wheat in intestinal homeostasis and the dietary management of inflammatory bowel disease (IBD) complications. In the fifth chapter, a liposomal delivery system based on Eudragit®-coated liposomes was developed to improve the stability and bioavailability of bioactive-rich fermented flour extracts (Lisosan G). These nanocarriers proved resistant to acidic environments and biocompatible with intestinal cells, confirming their potential for oral administration of fermentation-derived compounds. Taken together, the studies demonstrate that fermentation, through optimized fermentation processes, represents a powerful tool for developing sustainable functional foods capable of enhancing antioxidant defences, modulating inflammation, and supporting gut health.