Development, characterization, and validation of chitosan adsorbed cellulose nanofiber (CNF) films as water resistant and antibacterial food contact packaging

- Most compatible polysaccharides with cellulose nanofiber (CNF) was identified.
- Chitosan (CH) incorporated CNF films were fully characterized.
- CH reduced water solubility and enhanced antibacterial activity of CNF film.
- CH molecular weight and concentration impact functionality of CNF-CH film.
- CNF-CH films exhibited success to package food with wet surfaces.

Compatibility of CNF with three polysaccharides having different surface charges and backbones (chitosan, methyl cellulose, and carboxymethyl cellulose) was investigated. Chitosan (CH) incorporation reduced water absorption (WA) of CNF films (P < 0.05). CH molecular weight (Mw) (68, 181, 287 kDa) and amount (10 and 20 g/100 g CNF in dry basis) impacted moisture barrier, mechanical, antibacterial, thermal, and structural properties of CNF films. Regardless of Mw, CH incorporation (20 g/100 g CNF) decreased (P < 0.05) WA of CNF films, and high Mw (287 kDa) CH (20 g/100 g CNF) incorporation resulted in lower film water solubility while increasing film water vapor permeability compared with low Mw CH (68 kDa) incorporation (P < 0.05). CNF film with low Mw CH (20 g/100 g CNF) exhibited antibacterial activity against L. innocua and E. coli. Interaction mechanisms between CH and CNF were investigated through thermal, structural, and morphology analyses using DSC, FTIR, and SEM, respectively. CNF films with low or high Mw CH incorporation (20 g/100 g CNF) were further validated as surface contact films for fresh beef patties, showing effectiveness to prevent moisture transfer between the layered patties. This study demonstrated the potential of using CNF-CH composite films as water resistant and antibacterial packaging for foods with high moisture surfaces.