Fabrication of fucoxanthin-loaded composite nanoparticles based on lactoferrin and carboxymethyl chitosan: Interaction mechanism, stability and the application in filled hydrogel beads.

Fucoxanthin (FUC), a carotenoid naturally occurring in marine environments, has demonstrated various nutritional benefits. However, its application in the food industry is limited due to its inherent instability. This study aims to evaluate the ability of two types of lactoferrin (LF)-carboxymethyl chitosan (CMCS) complexes to encapsulate and stabilize FUC. These complexes were formed through physical mixing and enzymatic glycosylation. In the presence of CMCS, fluorescence spectra analysis revealed a static quenching interaction between LF and FUC. Furthermore, at a CMCS concentration of 0.3 wt%, the physical mixture and glycosylated LF exhibited enhanced binding affinity for FUC. FUC was encapsulated in the complexes via the antisolvent method, yielding FUC-loaded composite nanoparticles. FTIR spectroscopy and X-ray diffraction analyses confirmed the successful encapsulation of FUC within the nanoparticles, mediated by hydrogen bonding, electrostatic interactions, and hydrophobic forces. The higher FUC encapsulation efficiency and loading capacity were achieved in composite nanoparticles when the mass ratio was 10:2. Compared to free FUC and FUC-LF nanoparticles, the FUC-LC and FUC-LCTG nanoparticles exhibited superior stability, encompassing thermal stability, light stability, and storage stability. Moreover, when the nanoparticles were applied as active fillers in sodium alginate hydrogel beads, the network structure of the gel was enhanced. These complexes hold promise as novel and efficient delivery systems for carotenoid-like active molecules, with potential for diverse commercial applications.