Starch/Poly(butylene adipate-co-terephthalate) Blown Films Containing Quaternary Ammonium Salts and Ethylenediaminetetraacetic Acid for Food Preservation

In this study, quaternary ammonium salts (QAS) with different alkyl chain lengths (C12 and C18) were incorporated into starch/poly(butylene adipate-co-terephthalate) (PBAT) matrices with ethylenediaminetetraacetic acid (EDTA) to prepare blown films. The film with the combination of QAS and EDTA (D18D12E) achieved antibacterial rates of ≥99% against both Staphylococcus aureus and Escherichia coli, while maintaining cytocompatibility with HepG2 cells (viability ≥ 70%) and preliminary tobacco-growth compatibility. Compared with the control, the D18D12E film showed lower tensile strength (7.60 MPa) and higher oxygen (22.42 × 10−13 cm3·cm·cm−2·s−1·Pa−1) and carbon dioxide permeability coefficients (22.10 × 10−13 cm3·cm·cm−2·s−1·Pa−1). Its elongation at break (805.80%) and water vapor permeability (4.03 × 10−11 g·m·m−2·s−1·Pa−1) remained statistically comparable to those of the control. Furthermore, the D18D12E films delayed the visible deterioration of Chinese steamed bread and strawberries during 4 and 8 days of storage, respectively. These findings show that EDTA-assisted reduction in QAS loading can maintain antibacterial activity, but the associated mechanical and gas-barrier trade-offs require further formulation optimization.