Development of Antibacterial Biocomposites Based on Poly(lactic acid) with Spice Essential Oil (Pimpinella anisum) for Food Applications

Among the main biodegradable food packaging materials, poly-lactic acid (PLA) is a commercially successful polymer used notably in the food packaging industry. In this study, active PLA films containing different percentage of anise essential oil (AE) (0, 0.5, 1 and 1.5% v/v) were developed, and characterized by physical, mechanical and antibacterial analysis. Based on physical examinations, thermal stability of PLA/AE films was greater than the neat PLA film, and the minimum water vapor permeability (WVP) was recorded for PLA/0.5AE film (1.29 x 10(-11) g/m s Pa), while maximum WVP was observed for PLA/1.5AE (2.09 x 10(-11) g/m s Pa). Moreover, the lightness and yellowness of the composites were decreased by the addition of AE. For the PLA composites with 1.5% AE, the tensile strength decreased by 35% and the elongation break increased by 28.09%, comparing to the pure PLA. According to the antibacterial analysis, the minimum inhibitory concentrations of PLA/AE film were 5 to 100 mg/mL and the active composite could create visible inhibition zones of 14.2 to 19.2 mm. Furthermore, the films containing AE inhibited L. monocytogenes and V. parahaemolyticus in a concentration-dependent manner. The confirmation of the success of the incorporation of EOs into the PLA films was further evaluated using principal component analysis, where positive results were obtained. In this context, our findings suggest the significant potency of AE to be used as an antibacterial agent in active food packaging.

Automated summary

The study found that active PLA films containing different percentages of anise essential oil (AE) exhibited improved thermal stability and minimized water vapor permeability compared to neat PLA films. The addition of AE also led to changes in lightness and yellowness of the composites, as well as alterations in mechanical properties. Furthermore, the antibacterial analysis showed that the PLA/AE films had varying inhibitory effects on bacteria such as L. monocytogenes and V. parahaemolyticus, demonstrating the potential of AE as an antibacterial agent in active food packaging.