Physical, antioxidant, and preservation properties of chitosan film doped with proanthocyanidins-loaded nanoparticles

The nanoparticles (NPs) loading with proanthocyanidins (PC), obtained by crosslinking of chitosan (CH) and chondroitin sulfate (CS), were used as nanofillers in the matrix of the neat CH film, designing a novel edible bioactive packaging film. The electrostatic interaction and hydrogen bonding between NPs and the CH film matrix made the film denser, greatly enhancing the mechanical strength and barrier ability of the film. Moreover, NPs significantly improved antioxidability of the film and weakened the damage of ultraviolet rays and thermal effects on the biological activities of PC. The positive synergistic effect between the CH film matrix and NPs was established to effectively inhibit Escherichia coli, Staphylococcus aureus, and fish-original spoilage bacteria (Pseudomonas aeruginosa and Aeromonas hydrophila). In general, the addition of PC-loaded NPs to the CH film endowed the film with stronger antioxidant, antibacterial, and oxygen barrier effects, and could effectively slow down the quality deterioration of refrigerated grass carp fillets during storage, such as lower accumulation of total volatile base nitrogen and biogenic amines (putrescine, cadaverine, etc.) and more stable texture characteristics when compared to the control, confirming the potential in the application of food active packaging film.