Effect of Tannic Acid and Cellulose Nanocrystals on Antioxidant and Antimicrobial Properties of Gelatin Films

This work explored gelatin films incorporated with cellulose nanocrystals (CNC) and tannic acid as bio-based multifunctional food packaging materials. The effects of nonoxidized tannic acid (nTA), oxidized tannic acid (OTA), and CNC on the physical, antioxidant, and antimicrobial properties of gelatin films were investigated. Rheological and ultraviolet (UV)–visible measurements showed that gelatin films with nTA and CNC presented a lower chemical cross-linking and more noncovalent intermolecular interactions in comparison with those containing OTA. When compared to the film containing only nTA, the one with nTA and CNC presented substantial increases in the antioxidant capacity (52%), UV barrier (76%), tensile strength (79%), and water vapor barrier (67%) properties of gelatin. This evidence suggested that noncovalent interactions from nTA molecules and CNC play an important role in the modification of gelatin. The gelatin films designed with nTA and CNC also exhibited antimicrobial effects against Staphylococcus aureus and Escherichia coli. Overall, the incorporation of CNC and nTA as active components to gelatin films is a suitable approach for producing sustainable, multifunctional materials for food packaging and other applications.