Nanobiocomposites of carrageenan, zein, and mica of interest in food packaging and coating applications.

The present study presents the development and characterization of biocomposites of a red-algae-derived carrageenan, mica, and their blends with zein prolamine obtained by solvent casting. The morphology of the blends was characterized by scanning and transmission electron microscopy (SEM and TEM), optical microscopy, and atomic force microscopy (AFM). Mechanical behavior, water barrier, water uptake, and UV-vis protection of the cast films were also investigated. The results indicated that the addition of 10 wt % glycerol to the blends resulted in a better dispersion of the additive and, for that reason, a better improvement for the studied properties. The composites were seen colored but transparent and exhibited the ability to block the UV-vis radiation because of the characteristic absorbing properties of the filler. Nevertheless, the main conclusion from the work is that the nanocomposites were seen to act as a reinforcing plasticizer and also led to significantly reduced water permeability and uptake. The clay was found to be more efficient in the latter aspect than the zein prolamine as an additive. As a result, these novel carragenan-based biocomposites can have significant potential to develop packaging films and coatings for shelf-life extension of food products.