Background: The global shift towards sustainable packaging has intensified interest in polylactic acid (PLA), a bio-based and biodegradable polyester. However, PLA’s inherent brittleness, low thermal stability, and poor barrier properties against oxygen and moisture limit its widespread application in active food packaging. Incorporating nanofillers offers a viable strategy to overcome these limitations while imparting functional properties such as antimicrobial activity.

Objective: This study aims to develop and characterize novel PLA-based nanocomposite films reinforced with cellulose nanocrystals (CNC) and zinc oxide nanoparticles (ZnO-NPs) to enhance mechanical strength, barrier performance, and antimicrobial efficacy for fresh produce packaging.

Method: PLA/CNC/ZnO nanocomposites were fabricated via solution casting using chloroform as a solvent. CNC was extracted from microcrystalline cellulose via acid hydrolysis, and ZnO-NPs were synthesized via sol-gel method. Films were characterized using XRD, FTIR, SEM, TGA, and DSC. Mechanical properties (tensile strength, elongation at break), water vapor permeability (WVP), and oxygen transmission rate (OTR) were evaluated. Antimicrobial activity was tested against E. coli and S. aureus.

Key Results: The addition of 3 wt% CNC and 1 wt% ZnO-NPs resulted in a 45% increase in tensile strength and a 60% reduction in WVP compared to neat PLA. The nanocomposite exhibited significant inhibition zones against both bacterial strains, attributed to the synergistic effect of CNC barrier enhancement and ZnO-induced oxidative stress. Thermal stability improved by 15°C in onset decomposition temperature.