Cinnamon essential oil Pickering emulsions: Stabilization by bacterial cellulose nanofibrils and applications for active packaging films

Pickering emulsions are emulsions stabilized by solid particles with a wide range of potential applications as they typically provide more stable systems than surface-stabilized emulsions. Among the various solid stabilizers, bacterial cellulose (BC) may open up new opportunities for future Pickering emulsions due to its unique nanosize, amphiphilicity and other excellent properties. In this study, BC, TEMPO-oxidized BC (TOBC) and dialdehyde cellulose (DAC) were used as emulsifiers to stabilize cinnamon essential oil (CEO) Pickering emulsions. The microstructure, oil droplet size distribution, storage and loss moduli of the Pickering emulsions were affected by the type of emulsifier used. Compared to BC and DAC nanofibers, TOBC nanofibers exhibited better emulsifying capacity. TOBC (1%)-stabilized Pickering emulsion showed smaller droplet size, narrower size distributions, better stability and sustained release ability. Moreover, the Pickering emulsions showed high antibacterial activities against Gram-positive bacteria S. aureus and Gram-negative bacteria E. coli. Active gelatin composite films containing TOBC (1%)-stabilized CEO Pickering emulsions were successfully fabricated and showed good antibacterial and antioxidant properties, which make them suitable for food packaging application.