Enhancing food-derived bioactive components delivery: Impact of Fe3+/tannic acid metal-phenolic complexation on structure and in vitro release properties of cellulose nanofibers microgels

Precision nutrition represents a pivotal approach to enhancing human health, with food-derived bioactive components serving as its foundational elements, which are prone to inactivation and exhibit low bioavailability. Utilizing microgels, synthesized on the basis of cellulose nanofibers (CNF) as carriers for these bioactive components, presents a promising encapsulation strategy. Metal-phenolic networks (MPNs), renowned for their superior physicochemical properties, have been extensively employed in various fields. This study marked the first instance of employing the synergistic effect of Fe 3+ coordination cross-linking and MPNs to fabricate CNF-based microgel carriers for folic acid (encapsulation efficiency can reach 88%). Characterization by UV–Vis spectroscopy, XPS, XRD, FTIR and Raman spectroscopy , confirmed the formation of MPNs and further revealed the molecular interactions. The CNF-MPN microgels exhibited controlled release of folic acid (FA), and enhanced the bioaccessibility of FA (up to 91%), coupled with excellent antioxidant and antibacterial properties, with all measured activities exceeding 90%. These findings suggest that MPNs, as an enhancement strategy for CNF-based microgels, hold considerable promise for application in the delivery of bioactive components within the realm of food science . • CNF-MPN microgels were prepared using cellulose nanofibers, Fe³⁺ and tannic acid. • Folic acid was effectively encapsulated in CNF-MPN microgels. • CNF-MPN microgels enhanced the in vitro bioaccessibility of folic acid. • CNF-MPN microgels exhibited excellent antibacterial and antioxidant properties. • CNF-MPN microgels offer a new way for food-derived bioactive components delivery.