Oleogel Films Through the Pickering Effect of Bacterial Cellulose Nanofibrils Featuring Interfacial Network Stabilization

As bio-based food packaging materials promise a more sustainable future, this work fabricated edible oleofilms by casting beeswax-in-water Pickering emulsions, which were formed by the physical hybrid particles of bacterial cellulose nanofibrils (BCNFs) and carboxymethyl chitosan (CCS) (BC/CCS). The emulsion droplet size was varied from 4 to 9 mu m, and the emulsion index (El) was all up to 100%. The obtained emulsions exhibited excellent long-term stability, and there was no change in the El (100%) after the storage of the emulsion for 3 months. Moreover, the environmental temperature had almost no impact on the droplet size and El of the emulsion. The mechanical properties of the oleofilms were significantly improved by enhancing the content of BC/CCS. There was also a visual reduction in the water vapor permeability (WVP) value, which was lower than 1.1 x 10(-7) g.m(-1).h(-1).Pa-1. Furthermore, the obtained oleofilms exhibited a notable improvement in surface hydrophobicity, and surprisingly, it could be easily redispersed into water to recover back to the emulsion state without additional high energy mixing. This suggested that this edible oleofilm was prepared by a fully green method by casting Pickering emulsions stabilized by BC/CCS and could extend its application for the development of food-grade coating materials.