Integrated strategies to overcome lignocellulosic recalcitrance for the recovery, fractionation and characterization of functional fibers

Lignocellulosic by-products from the agri-food industry represent a largely underutilized source of dietary fibers. Recovering these fractions is challenging due to their structural diversity across plant species and their recalcitrant structure, which often requires harsh treatments that can degrade or chemically modify the polymers. This thesis investigated strategies for the selective recovery and fractionation of, primarily, insoluble fibers from plant residues, focusing on preserving their native structure and, consequently, functional properties. Diverse extraction schemes were investigated, integrating pre-treatments involving non-carbohydrate-hydrolyzing enzymes, bacterial fermentation and mechanical disruption, combined with temperature-controlled hydrothermal extraction, and innovative solvent-assisted techniques, all aimed at enhancing the solubilization of insoluble fibers in mild conditions. Comprehensive molecular characterization of the recovered fractions was performed to elucidate the mechanisms underlying each treatment and to assess the functional potential of the resulting products.