Development and characterization of agar-based edible films reinforced with nano-bacterial cellulose

Nano-bacterial cellulose (BC), as a reinforcing agent, was used to prepare the agar-based edible films. Effects of BC content (0, 3, 5, 8 and 10%, wt% based on the agar) on the rheological properties of film-forming solution (FFS), and on structure, morphology, crystallinity, and thermal properties of films were investigated. Results of rheological and FTIR analyses revealed that interactions between BC and agar were formed through hydrogen bonds. The crystallinity and the thermal stability of films were improved by addition of BC analyzed by XRD and TGA, respectively. Compared with high BC concentrations (8-10%), a good dispersion of BC at low concentrations (3-5%) in the films was observed by SEM. Moreover, BC addition (10%) significantly decreased moisture content (MC), water solubility (WS) and water vapor permeability (WVP) by 60.4%, 13.3% and 25.7%, respectively. The tensile strength (TS) of films increased from 22.10 to 44.51 MPa after addition of BC (0-10%), whereas the elongation at break (EAB) initially increased with increasing BC concentrations (0-5%), and then decreased with further addition of BC (8-10%). Consequently, agar-based edible films reinforced by moderate nano-BC have the potential as a packaging film for food products.