Properties and application of antioxidant and antibacterial composite films based on methylcellulose and spine grape pomace fabricated by thermos-compression molding.

Methylcellulose (MC)/grape pomace (GP) films, plasticized with either glycerol (GLY) or cinnamon essential oil (CEO), were prepared by thermo-compression molding and characterized. Compared to the GLY-plasticized MC50/GP50 films, a considerable increase in TS and YM values of CEO-plasticized films was observed, rising from 9.66 to 30.05 MPa, 762 to 1631 MPa, respectively. Moreover, the water vapor barrier, surface hydrophobic properties, and antioxidant/antibacterial activities of CEO-plasticized films remarkedly improved with increasing CEO content from 5 to 15% w/w. From scanning electron microscopy, phase separation between GP and the MC/GLY mixture were evident for GLY-plasticized MC/GP films. On the other hand, the CEO-plasticized films showed compact morphologies, attributable to the formation of hydrogen bonding and π-π stacking interaction. Preliminary shelf-life study on showed that fresh chicken wrapped with the CEO-plasticized MC/GP films exhibited lower TVB-N, TBARS, and TVC values than the unwrapped control samples, during 7 d storage at 4 °C.

Bioinspired pullulan-starch nanoplatelets nanocomposite films with enhanced mechanical properties.

Inspired by the leaf-vein network structure, the pullulan-starch nanoplatelets (SNPs) bioinspired films with enhanced strength and toughness were successfully fabricated through a water evaporation-induced self-assembly technique. SNPs (SNP200 and SNP600) of two sizes were separated by differential centrifugation. Interactions between SNPs and pullulan during drying resulted in the vein-like network structure in both nanocomposite films when the appropriate amounts of SNP200 or SNP600 were added to pullulan, respectively. The TS and toughness values of pullulan with 1 % w/w SNP200 films reached up to 51.05 MPa and 69.65 MJ·m-3, which were 86 % and 223 % higher than those of the neat pullulan films, respectively. Moreover, the TS and toughness values of pullulan-SNP200 were significantly higher than those of pullulan-SNP600 films, when SNP content exceeded the 1 % w/w level. By applying a graph theory, the network structures were found to correlate with the mechanical properties of the pullulan-SNPs bioinspired films. The new strategy for designing starch nanoplatelets-based edible films that combine mechanical strength and toughness holds promises for the development of novel biobased composite materials for food packaging application.