Valorization of Bay Leaf Essential Oil as a Bioplasticizer and Antibacterial Agent in Polybutylene Adipate-co Terephthalate Biofilms for Food Packaging Applications

Abstract

Although the high flexibility of PBAT (polybutylene adipate-co-terephthalate) makes it ideal for food packaging, its poor antibacterial properties restrict its use in the food industry and shorten the shelf life of food products. In this work, PBAT polymer film was modified with bay leaf essential oil to improve its antibacterial properties. Gas chromatography-mass spectrometric analysis showed 38 chemical components in bay leaf. The main absorbances were the strong C=O stretching of the ester group (1720 to 1730 cm⁻¹) and the aliphatic C–H stretching (2950 and 2850 cm⁻¹). An increase in the amount of essential oil resulted in a decrease in the melting temperature of the PBAT, confirming a plasticizing effect. No antibacterial activity was observed in the PBAT films containing 5 wt% or 10 wt% bay leaf oil against either gram-positive or gram-negative bacteria. However, PBAT films containing 15 wt% and 20 wt% bay leaf oil exhibited zone diameters of 8 and 12 mm, respectively, against the E. coli strain. PBAT films with enhanced plasticizing and antibacterial properties, resulting from the addition of 20 wt% bay leaf oil, could be of great interest to the food packaging and biomedical industries.