Biodegradable Cellulose and Cellulose Nanofibres-Based Coating Materials as a Postharvest Preservative for Horticultural Products

Currently, the packaging material is composed of fossil fuel-based plastics, which are non-biodegradable. Therefore, the biodegradable coating material developed from cellulose can be explored for applications like packaging, cutlery, bowls, straws, etc. The aim of the present study was to develop an agro-waste-based sustainable coating material using a waste-to-wealth approach. The study focused on transforming cellulose and cellulose nanofibre (CNF) derived from rice straw into biodegradable polymeric coatings. The cellulose and CNF were extracted from the rice straw using the alkali method and blended with gelatin, agar, and varied glycerol concentrations to initiate the study. Four polymeric coating variants were developed. Thus, the coating named NCG-2.5, incorporated with 1.2 g CNF, 2.5 ml glycerol, 1.15 g gelatin, and 0.55 g agar, exhibited significant improvements in properties as compared to the other samples. The polymeric coatings were characterized for their surface morphology, roughness, solubility, and physico-chemical properties using FTIR spectroscopy and TGA analysis. The NCG-2.5 exhibited the best potential in terms of promising coating and biodegradability properties, with 97% of weight loss within 7 days. Furthermore, the studies where the synthesized polymeric coating was applied to the surface of the banana proved a considerable delay in the enzymatic browning of the banana for up to 12 days. Thus, the study reflects the novel approach of value addition and utilization of waste agricultural resources for developing coating materials via a circular economy approach.