Sustainable active packaging films from pla and pbat with thyme oil: Extending the shelf life of cherry tomatoes

Abstract

This study aimed to develop antimicrobial and biodegradable packaging films with excellent printability, designed to preserve the freshness of cherry tomatoes, using polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), and natural thyme oil. Packaging films were prepared using the solvent casting method by incorporating 1%, 2.5%, and 5% (w/v) thyme oil into PBAT and PLA-based polymer matrices. Fourier-transform infrared (FTIR) spectroscopy confirmed the successful integration of thyme oil into PBAT, PLA, and PBAT/PLA polymeric matrices. When the concentration of thyme oil increased from 1% to 5%, the antibacterial properties against Staphylococcus aureus improved by 42% in films containing only PBAT, 46% in the films containing only PLA, and 28.5% in PBAT/PLA films. Similarly, for Escherichia coli, the improvements were 37.5%, 28.5%, and 45.5%, respectively. The water contact angle measurements revealed that the packaging films exhibited a certain degree of hydrophobicity. A packaging film incorporating 5% thyme oil (TO) (by total weight) into the PBAT and PLA polymeric matrix (PBAT/PLA-5TO) exhibited effective antibacterial properties and extended storage stability. The PBAT/PLA-5TO packaging film was found to extend the shelf life of cherry tomatoes sevenfold, significantly reducing spoilage rates and demonstrating remarkable effectiveness in prolonging shelf life. In conclusion, the packaging films prepared by incorporating thyme oil into the polymeric matrix present an innovative and biodegradable packaging material that offers a sustainable solution for the food packaging industry.