Chitosan/cellulose nanocrystal biocomposite coating for fruit postharvest preservation

Abstract

Storage and transportation of fresh fruits and vegetables result in significant wastage, making their preservation post-harvest a global issue. Although petroleum-based synthetic wax is commonly used in fruit post-harvest preservation due to its effectiveness, its adverse effects on ecological environment and human health cannot be ignored. Hence, it is imperative to explore natural and sustainable coatings that can serve as an eco-friendly and healthy alternative to petroleum-based synthetic waxes for fruit preservation. In this study, we developed a biocomposite coating based on chitosan (CS) as the bio-based film forming material, cellulose nanocrystals (CNC) as the reinforcement and sodium tripolyphosphate (TPP) as the crosslinking agent. By employing the dip coating process, it becomes feasible to apply micron-sized films onto the surfaces of diverse perishable fruits. The results revealed that the CNC and TPP significantly enhanced mechanical strength, oxygen barrier performance, thermal stability, antibacterial activity, and hydrophobicity of the coating. As a proof-of concept, bananas were utilized as experimental samples to investigate the impact of the coating. The findings demonstrate the efficacy of this coating in preserving the fruit's visual appeal and prolonging its storage duration. The coating can be used in various scenarios and on different products, having excellent potential in preservation technology, transportation and storage of postharvest agricultural products. The utilization of a multifunctional coating based on chitosan represents a promising and sustainable approach to address the pressing issue of global food waste. This innovative coating offers a cost-effective solution to effectively reduce postharvest losses of perishable foods, contributing to a more sustainable food system.