Effect of chitosan molecular weight on the stability and bioaccessibility of nanoemulsions for lycopene preservation.

Abstract

Lycopene, a potent antioxidant, has limited application in food systems due to its chemical instability and low bioaccessibility. Therefore, this study aimed to enhance the bioaccessibility, physicochemical stability, and antioxidant stability of lycopene by encapsulating it in nanoemulsions stabilized with chitosan of different molecular weights. Chitosan was modified through depolymerization reactions to obtain different molecular weights and used to formulate and stabilize nanoemulsions, which were then characterized for their physicochemical properties. The nanoemulsions exhibited high encapsulation efficiency (≥ 94.1 %) and mean particle sizes below 100 nm. Antioxidant stability analysis revealed that increasing chitosan molecular weight improved the protective effect on lycopene. Nevertheless, nanoemulsions prepared with the lowest molecular weight chitosan significantly enhanced lycopene bioaccessibility, reaching 17.9 %, compared to the free compound. This improvement was attributed to the protective nature of the chitosan matrix and the reduced particle size. These findings suggest that the developed nanoemulsions are a promising strategy for incorporating lycopene into food products, potentially enhancing their nutritional and functional value.