Functionalization of a poly(lactic acid)/poly(butylene adipate-co-terephthalate)/thermoplastic starch film with olive leaf extract and its impact on postharvest green pepper quality

In the context of packaging innovation, active packaging using biodegradable polymers offers a viable alternative for preserving fresh products by ensuring microbial stability and reducing cold damage. This eco-friendly approach also combines green technology (supercritical impregnation) and a natural olive leaf extract (OLE). The development films exhibited, especially on those impregnated at 400 bar/55 °C, a suitable impregnation level (19.8 ± 3.2 % w/w OLE) and significant antioxidant activity (0.44 ± 0.08 gTEAC/100g film) to exert preservative action. Moreover, OLE preserved the water barrier properties and enhanced light-blocking capabilities of films. These properties were key to the extension of the shelf life of green peppers, as the impregnated films provided better color protection and reduced aerobic counts (3.95 ± 0.10 against 4.50 ± 0.08 log CFU/g) compared to non-impregnated films, reducing the chilling injury symptoms in 20 days of assay. • Olive leaf extract (OLE) boosts antioxidant activity in biodegradable food films. • OLE was successfully incorporated into films via supercritical solvent impregnation. • OLE impregnation preserves water barrier properties and improves light-blocking. • Impregnated films improve antimicrobial protection in green pepper packaging.