Study on intermolecular interactions of agar, κ-carrageenan and cellulose nanofiber and their application in food packaging film

Future food packaging trends are shifting toward degradable and even edible materials developed from natural polysaccharides, in order to reduce the pollution caused by synthetic polymers. In this article, a series of dispersion systems of agar (AG), κ-carrageenan (KC), cellulose nanofiber (CNF), as well as their composite systems were systematically prepared, and their corresponding physicochemical properties and application in food packaging film were investigated. The results showed that the intermolecular interactions between AG and KC molecules led to the formation of AG double helix, AG/KC double helix, and KC double helix in AG/KC composite system. Then the double helix structures interleaved with each other during the further cooling process, and new aggregate structures should be formed. Similar phenomena occurred in AG/CNF and KC/CNF composite systems. The optimum preparation technology of Ca 2+ -AG/KC/CNF edible nanocomposite film was obtained by preliminary single-factor experiment and response surface methodology (RSM). Compared with pure polysaccharide films, two-component composite films, and some plastic films, the prepared nanocomposite film possessed excellent optical properties, mechanical properties, good thermal stability and freshness retention performance. The results showed that the new Ca 2+ -AG/KC/CNF edible nanocomposite film had great potential for food packaging application.