High-molecular-weight fibroin as a preservation coating for perishable fruits

Fresh fruits and vegetables are prone to spoilage during storage. To prolong the shelf life of perishable produce, various preservation technologies, such as plastic packaging, are widely used; however, many contribute to environmental pollution and food safety concerns. This study developed a simple and scalable coating solution based on high-molecular-weight (MW) fibroin for preserving fresh fruits. Specifically, the lightly-degraded silk protein was blended with edible alcohol to prepare the preservation coating solution. The incorporation of a moderate ethanol concentration (15%) not only promoted structural transition of fibroin into a β-conformation and enhanced preservation efficacy, but also eliminated the need for additional annealing steps and lowered production costs. The resulting coating film exhibits excellent mechanical strength and optimal barrier properties, effectively delaying decay while significantly extending the shelf lives of winter jujube and avocado. This protein-based, potentially eco-friendly coating strategy demonstrates promising economic prospects for post-harvest preservation and sustainable agricultural practices.