Active Mono-Material Films from Natural and Post-consumer Recycled Polymers with Essential Oils for Food Packaging Applications

Packaging systems are facing a paradigm shift where challenges like recycling issues, non-biodegradable nature, and the migration of harmful chemical substances into food need to be solved. As a response, active packaging from sustainable materials has gained attention. Considering this, the extrusion process was employed to elaborate active mono-material films and elucidate the internal interactions between different content (0, 2.5, 5, and 7.5%) of inclusion complexes (IC) based on β-cyclodextrins (β-CD)/essential oils (orange or thyme) and sustainable materials such as biopolymers (PLA) and post-consumer recycled polymers (rHDPE). The thermal, morphological, mechanical, and antifungal properties of the films were evaluated. The addition of IC produced structural changes in the rHDPE films that promoted ordered matrix structures, as indicated by the changes in crystallinity. Furthermore, the PLA films containing β-CD-Orange or β-CD-Thyme showed smoother and more homogeneous surfaces, showing higher compatibility and interfacial adhesion between the ICs and the biopolymer, which resulted in better antifungal activity against Penicillium funiculosum hyphae growth. The results showed an alternative for the use of biopolymers and post-consumer recycled polymers to develop stiff (PLA) and less stiff (rHDPE) sustainable active packaging, which constitutes an interesting topic for further studies.