A Biodegradable and Active Bilayer Nanocomposite Obtained from Starch-Yerba Mate Extract and Starch-TiO₂ Nanoparticles Films for Packaging Applications

Growing environmental concerns and consumer demand for safe food lead to the innovation of biodegradable and active packaging materials. In this work, a biodegradable and active bilayer nanocomposite (TPS-Y/NP) from two cassava starch-based film layers is developed by casting, for possible use as packaging that can extend food shelf life. One layer is composed of a starch-yerba mate extract film (TPS-Y) and the other of a starch-titanium dioxide nanoparticles nanocomposite (TPS-NP). The use of the same starch matrix (TPS) in both films achieves a material with excellent interlayer compatibility. The bilayer presents activity against different pathogens and improvements in mechanical resistance and water vapor permeability (WVP) due to the contribution of the nanocomposite layer, and it shows antioxidant activity and greater deformation due to the layer with the natural extract. In addition, all films degrade in vegetable compost almost completely in two weeks. This bilayer film can be promisingly employed as a biodegradable and functional packaging to improve the useful life of food by conferring antioxidant and antibacterial activity.