Development of PLA-Based Active Packaging Films Plasticized with a Deep Eutectic Solvent and Enriched with Sumac (Rhus coriaria L.) Extract

In this study, the plasticizing effect of a deep eutectic solvent (DES) on polylactic acid (PLA) films mixed with sumac extract (SE) was investigated. DES (ChCl-Lev), consisting of choline chloride (ChCl) and levunic acid (Lev), was used. Chemical analysis confirmed the synthesis of ChCl–Lev and demonstrated the effective integration of the ChCl–Lev and SE system into PLA films. Incorporation of ChCl–Lev into the film led to an approximately 76% increase in elongation at break. This increase continued at approximately 49% in the film with 1% SE (SE1_ChCl-Lev10) additive. Antioxidant activity increased with SE content, reaching ABTS and DPPH scavenging activities of 96% and 83% at 1% SE (SE1_ChCl-Lev10) and 98% and 91% at 10% SE (SE10_ChCl-Lev10). Furthermore, antibacterial activity increased significantly as SE concentration increased; the film containing 10% SE showed strong inhibition against Staphylococcus aureus at a rate of 96.95 ± 0.32, while the inhibition rate against Escherichia coli also increased to 26.68 ± 2.89, whereas no antibacterial activity was observed in pure PLA. Considering these findings, it is anticipated that films produced using an innovative strategy could be a potential candidate for packaging, active food contact materials, and biomedical applications.