Bacterial cellulose nanofibers used as nanofillers improved the fresh-keeping performance of gelatin-based edible coating for fresh-cut apples

In this study, bacterial cellulose nanofibers (BCNs) (0%, 1%, 2%, and 3%) were used as nanofillers to prepare gelatin-based edible films, and their physical properties and fresh-keeping performance were investigated. The microstructure observation showed that the BCNs were well dispersed in the gelatin-based edible films and the surface roughness of the films increased with the increase of BCNs content. X-ray diffraction and thermogravimetric analysis showed that the crystallinity and thermal stability of the film were significantly increased with the increase of BCNs. Fourier-transform infrared spectroscopy analysis suggested that hydrogen bond interactions occurred between BCNs and gelatin polymers, leading to improved mechanical properties with the increase of BCNs content. Furthermore, the barrier performance was also improved with the increase of BCNs content, where gelatin-based edible films with 2% BCNs showed the best mechanical property. Meanwhile, the gelatin-based film-forming solutions (FFSs) containing different BCNs were coated on the fresh-cut apples and the corresponding fresh-keeping performance was investigated. The results showed that the fresh-keeping parameters of fresh-cut apples coated with FFSs containing BCNs were better as compared with those of pure gelatin FFSs. Moreover, the fresh-keeping parameters were improved with the increase of BCNs, especially the FFSs containing 2% BCNs that showed the best fresh-keeping parameters. Therefore, BCNs, used as nanofillers, are an excellent enhancer to improve the fresh-keeping performance of the gelatin-based edible coating, showing a promising potential application in the food preservation field.