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 <i>Staphylococcus aureus</i> at a rate of 96.95 ± 0.32, while the inhibition rate against <i>Escherichia coli</i> 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.