Cellulose-based intelligent packaging films with antibacterial, UV-blocking, and biodegradable properties for shrimp freshness monitoring

The development of sustainable and functional packaging materials has become a very promising way to reduce pollution from traditional plastics. To address the shortcomings of natural materials with single function, poor antimicrobial and mechanical properties, and to develop more competitive green food packaging, a sodium carboxymethyl cellulose based multifunctional packaging film interspersed with wheat straw cellulose fibers (CF) and cellulose nanofibers (CNF) was proposed in this study, where CF and CNF increased the surface area of the film and loading capacity of the functional materials at the micrometer and nanometer levels, respectively. A biodegradable supramolecular polymer, polydiacetylene (PDA), was introduced into the film. Then, ZnO nanoparticles and PDA carboxylate head group coordination self-assembly strategy was utilized to build a PDA/Zn2+ intercalation composite structure, which was able to produce a highly sensitive specific response to biogenic amine and endowed the film with the ability of visual indication, as well as to effectively improve the film's antimicrobial, ultraviolet light shielding, gas barrier, and water resistance properties. Moreover, the dense structure enables the film to withstand more than 50 reciprocal folds of nearly 180°, far exceeding that of ordinary packaging paper (about 10 folds). Composite packaging film enabled effective quality retention and spoilage monitoring of high protein products, especially shrimp with high biogenic amine release. This study provides a valuable reference for the application of supramolecular polymers, such as PDA, in food packaging materials, and gives a diversified development idea for plastic alternative packaging and multifunctional food packaging.