TEMPO-oxidized cellulose nanofiber/chitosan composite films stabilized by cumin essential oil-loaded Pickering...

Designing multifunctional packaging films that combine barrier protection, antimicrobial activity, antioxidant capacity, and controlled-release functionality is crucial for extending the shelf life of perishable foods. This study presents the first incorporation of cumin essential oil-loaded Pickering emulsions into a TEMPO-oxidized cellulose nanofiber (TOCNF)/chitosan (CS) matrix for the construction of bio-based active films. Cumin essential oil encapsulated in Pickering emulsions stabilized by sodium caseinate and β-cyclodextrin, carried negative charges that interacted with positively charged CS via electrostatic attraction and hydrogen bonding, thereby strengthening interchain cross-linking and film stability. Structural analyses confirmed the strong compatibility between Pickering emulsions and the TOCNF/CS matrix, accompanied by enhanced thermal stability. Performance evaluations showed that the composite film possessed outstanding mechanical strength (up to 45.2 MPa), a markedly reduced water vapor transmission (~60%), lower oxygen permeability, and improved water resistance. In addition, incorporation of CEO-loaded Pickering emulsions significantly improved the functional properties of the films. The antioxidant activity increased by approximately 210%, while the composite films exhibited pronounced antibacterial activity, with inhibition zone diameters of 19.5 mm for Staphylococcus aureus and 24.00 mm for Escherichia coli. Preservation tests on tomatoes and blueberries demonstrated significantly reduced weight loss, delayed firmness decline, and moderated pH changes, confirming extended shelf life. Overall, this study provides an innovative method for designing sustainable packaging films that integrate sustained release with multifunctional protection, highlighting their potential for practical application in perishable food preservation.