# Sustainable PLA–Citronella Essential Oil Films: Development and In Vitro Antifungal Evaluation for Potential Blueberry Packaging Applications

## TL;DR

This study develops biodegradable films with citronella oil to prevent fungal spoilage in blueberries, offering a sustainable packaging solution.

## Contribution

The novel contribution is the development and evaluation of PLA films enriched with citronella essential oil for antifungal packaging.

## Key findings

- PLA films with citronella essential oil showed concentration-dependent antifungal activity against blueberry spoilage fungi.
- Citronella oil incorporation did not significantly affect water vapor barrier properties of PLA films.
- The antifungal mechanism involved membrane disruption and morphological damage in fungal hyphae.

## Abstract

Postharvest fungal decay is a primary cause of losses in blueberries, motivating the development of sustainable alternatives to conventional fungicides. This study aimed to develop and evaluate antifungal active films based on polylactic acid (PLA) enriched with citronella essential oil to control phytopathogenic fungi associated with blueberry spoilage. PLA films containing 7.5, 10, and 12.5% (w/w) citronella essential oil were produced by solvent casting and characterized for water vapor transmission rate and nanomechanical properties. The antifungal effect was tested in vitro against Epicoccum nigrum, Alternaria alternata, and Cladosporium herbarum. Active films exhibited concentration-dependent antifungal activity, with C. herbarum being the most sensitive fungus. The incorporation of citronella essential oil did not significantly alter the water vapor barrier properties of PLA, while mechanical analysis revealed a reduction in elastic modulus only at the highest concentration. The antifungal mechanism was elucidated using scanning electron microscopy, fatty acid profiling, absorbance at 260 nm, and conductivity measurements. The results indicate that the released citronella essential oil induced membrane disruption and morphological damage in fungal hyphae, with species-specific responses. Overall, PLA–citronella essential oil films represent a promising biodegradable packaging solution to control postharvest blueberry losses.