Development of antibacterial starch-based PLA/PBAT active packaging films for enhanced beef preservation

Starch is a natural polymer material that is widely sourced, biodegradable, and non-toxic. However, the application of starch is hindered by its hydrophilicity and lack of biological activity. In this study, ε-polylysine hydrochloride (ε-PLH) was grafted onto starch for improving antibacterial properties of starch and weakening its hydrophilicity. Subsequently, a new type of active packaging film was prepared by blending polylactic acid (PLA), polybutylene adipate terephthalate (PBAT) and grafted starch (ε-PLH-g-starch) using the melt extrusion method. ε-PLH-g-starch/PLA/PBAT film can effectively inhibit Escherichia coli and Staphylococcus aureus with inhibition rates of 48.62 ± 2.43 % and 57.31 ± 1.65 %, respectively. The addition of ε-PLH-g-starch also significantly improved the tensile strength, optical properties and barrier properties of the films. As a verification experiment, the application of ε-PLH-g-starch/PLA/PBAT film can effectively inhibit the protein hydrolysis, microbial growth and fat oxidation of beef, and extend the shelf life of beef at 4 °C from 7 to 14 days.