Bio-Derived Active Packaging: Genipin-Cross-Linked Chitosan/Cellulose Nanocrystal Films Embedded with Lemongrass Essential Oil for Extended Post-Harvest Fruit Life

Abstract

Chitosan-based films are attractive eco-friendly substitutes for petrochemical packaging; however, their commercialization is limited by modest mechanical strength and limited functionality. This study presents a fully bio-sourced composite in which chitosan is covalently cross-linked with the natural reagent genipin, nano-reinforced with sulfonated cellulose nanocrystals (CNCs) and functionalized with lemongrass essential oil (LEO) as a broad-spectrum antimicrobial. Spectroscopic, microscopic, and thermal analyses confirmed the formation of a densely reticulated architecture through Schiff-base chemistry and hydrogen bonding. The optimized CS/G/CNC/LEO film reached a tensile strength of 49 MPa (above 80% higher than pure chitosan), showed a 74% fall in swelling ratio, and exhibited superior O₂ and UV barriers. As a coating for cherry tomatoes, the material restricted weight loss to 9%, preserved firmness, titratable acidity and vitamin C, suppressed microbial growth and respiration, and prolonged post-harvest shelf life by six days under room temperature storage conditions. These results demonstrate the potential of CS/G/CNC/LEO films as a sustainable active food packaging material.