Thermo-pressed blend films of poly(lactic acid)/poly(butylene adipate-co-terephthalate) with polylimonene for sustainable active food packaging

Abstract

Poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) blends provide sustainable packaging solutions renowned for their robustness and biodegradability. Herein, we used a commercial PLA/PBAT blend (Ecovio® - E) to develop films by thermo-pressing, incorporating polylimonene (PLM) and comparing them with limonene (LIM) at 5% and 10% additive concentrations. Remarkably, E/PLM10% film exhibited an 84.9% reduction in Staphylococcus aureus count and a 62% decrease in Aspergillus niger count, surpassing LIM and PLA/PBAT. Additionally, PLM substantially improved the antioxidant activity of the films, achieving more than 40% DPPH scavenging and providing light-blocking capability, with E/PLM5% virtually halting UV-A transmission. Mechanical assessments showed that, although higher PLM levels reduced tensile strength, E/PLM5% matched control performance. FT-IR analysis confirmed PLM presence without chemical alterations, and minimal changes in crystallinity were observed via DSC and XRD, while TGA confirmed the attractive thermal stability of the films. Expanding on these findings, we evaluated film efficacy in cherry tomato preservation, including unpackaged controls. E/PLM5%-packaged tomatoes exhibited superior visual quality and fungal inhibition, proving a promising option for active food packaging due to their antimicrobial effectiveness, antioxidant activity, and UV-light protection. Therefore, this study represents significant progress in advanced packaging development, providing prolonged food preservation, sustainability, and retained performance even when prepared in simulated industrial conditions.