Active PLA thermoformed trays incorporating EDTA, ethyl maltol and ethyl lauroyl arginate: Synergistic antimicrobial and antioxidant packaging for refrigerated meat products

Polylactic acid (PLA)-based thermoformed trays incorporating antibacterial and antioxidant agents offer a sustainable alternative to single-use plastic packaging and help reduce food waste. Active PLA sheets were prepared via cast extrusion with 5 wt% of ethylenediaminetetraacetic acid (EDTA), ethyl maltol (EMAL), or ethyl lauroyl arginate (LAE). Binary mixtures of EDTA/LAE and EMAL/LAE were formulated at 5 and 10 wt% to enhance broad-spectrum antibacterial performance. X-ray diffraction and differential scanning calorimetry suggested that EDTA/LAE more significantly influenced PLA crystallization and induced β-form crystals formation compared to EMAL/LAE. This led to decreased thermal stability, reduced tensile strength, and increased elongation at break. LAE significantly increased water vapor permeability. EMAL/LAE reduced oxygen permeability (OP) by 68 %, while the EDTA/LAE increased OP by 57 %. LAE showed a combined antibacterial effect in PLA/EDTA sheets against both types of bacteria (Gram-positive and Gram-negative) when compared to PLA/EMAL sheets. PLA/EMAL sheets showed excellent DPPH scavenging activity. To evaluate antimicrobial efficacy in food, bacon slices were placed between two sheets and sealed in polypropylene bags to prevent external contamination during 4 °C storage. The EDTA/LAE combination showed a strong synergistic antimicrobial effect, reducing bacterial counts by more than 4 logs in bacon after 7 days. These findings suggest that PLA/EDTA/LAE trays are promising for antibacterial packaging, while PLA/EMAL/LAE trays provide both antibacterial and antioxidant functionality.