Olive leaf extract as a natural antioxidant and antimicrobial additive in biodegradable PLA film and its potential utilization in active packaging

Abstract

This study explores the development of a biodegradable film based on plasticized polylactic acid (PLA), incorporating olive leaf extract (OLE) to impart antimicrobial and antioxidant properties for potential use in the packaging of fruits and sensitive vegetables. Films were prepared using the casting method with triacetin as a plasticizer and three OLE concentrations (3%, 5%, and 8%). The addition of OLE induced notable changes in the colour, mechanical, and thermal properties of the films. The obtained films exhibited potent antioxidant activity and notable antibacterial effects against different bacterial strains. Migration tests, conducted by assessing the phenolic content and HPLC-DAD analysis to quantify released phenolic compounds, revealed a moderate migration rate below a 5% OLE content. Biodegradation tests demonstrated high carbon mineralization rates exceeding 50% over 60 days under burial and composting conditions. The PLA–OLE film effectively preserved high quality for 21 days at 4 °C, significantly extending the shelf life when used as active packaging for cherry tomatoes.