Role of hydrothermally prepared CeO2 in developing chitosan-based functional coating for banana preservation

Abstract

This work aims to construct a nanocomposite coating made from chitosan (CS) and hydrothermally prepared ceria nanoparticles (hCeO2 NPs), and thoroughly evaluate its influence on extending the lifespan of post-harvest bananas over a 12-day period. The hCeO2 NPs were characterized to confirm their synthesis before being integrated within the CS matrix. The morphological, structural, mechanical, water-, and UV-barrier properties of nanocomposite coating films were determined. Furthermore, the physicochemical properties of the fresh banana, such as visual attributes, peel color, respiration rate, firmness, weight loss, total soluble solids, titratable acidity, ripening rate, and pH, are thoroughly considered throughout storage. Results showed that the water permeability, solubility, swelling index, fracture resistance, and flexibility are significantly enhanced by adding 1-2% (w/w) hCeO2 NPs. Notably, a 3.5- and 1.6-fold increase in the fracture strength and plasticity of CS was achieved by adding 1.5% (w/w) hCeO2 NPs. The great UV-barrier function of the hCeO2-loaded CS nanocomposite coating films in UVB and UVC is found. For banana preservation, the CS-1.5%-hCeO2 nanocomposite coating manifested its superior efficiency in retarding the banana ripening compared to CS, commercial chitosan products, and uncoated fruit, extending the expiration date of fresh bananas without deteriorating the fruit's physicochemical characteristics.