Incorporating of Oxidized Cellulose Nanofibers@d-Limonene Pickering Emulsion into Chitosan for Fully Biobased Coatings toward Fruits Protection

Due to the perishable nature and limited shelf life, it is crucial to develop highly efficient techniques for fruit preservation while avoiding the use of environmentally hazardous materials. Herein, the ecofriendly oxidized cellulose nanofibers (OCNF) with an optimized solid content (1.0 wt %) was utilized to stabilize d-Limonene to form an oil-in-water Pickering emulsion. By incorporating the Pickering emulsion into chitosan (Cs) solution, fully biobased Cs/OCNF@d-Limonene coatings were successfully obtained via a simple solvent casting method. Thanks to the physical cross-linking and hydrogen bond reaction between OCNF and Cs matrix, the films exhibited high transmittance, high haze, exceptional mechanical properties, and the ability to effectively shield 96.5% UVB and 69.3% UVA radiation. Most importantly, the inclusion of d-Limonene exhibited a remarkable enhancement in the inhibition zones against E. coli and S. aureus, and an outstanding 72.5% improvement in antioxidation properties. These outstanding film properties make the Cs/OCNF@d-Limonene coatings ideal as conformal films for fruit protection, which can effectively reduce the fruit water loss rate, delay ripening, prevent oxidation and microbial invasion, and significantly extend the shelf life of fruits. The well-designed coatings present a promising, cost-effective, and sustainable alternative to conventional plastic packaging materials for fruit protection.