Applications of plant-derived food by-products to maintain quality of postharvest fruits and vegetables

The continuous growth of the world's population has driven the increased demand for fresh fruits and vegetables. Most postharvest fruits and vegetables are susceptible to quality loss and diseases during transport and storage. Numerous studies targeting the preservation of postharvest fruits and vegetables have hitherto been carried out. The processing of plant-derived food unavoidably generates a raft of by-products, which tends to be discarded as food waste. However, plant-derived food by-products (PDFBPs) contain abundant high added-value materials, which have the potential to maintain the postharvest quality of fruits and vegetables. This review attempts to summarize materials that are prepared from PDFBPs demonstrating the potential to maintain the quality and extend the shelf-life of postharvest fruits and vegetables. In addition, recent studies investigating the preservation effects of materials obtained from PDFBPs on postharvest fruits and vegetables are comprehensively reviewed. PDFBPs are economical sources of diverse high added-value materials, some of which exhibit the potential to maintain the postharvest quality of fruits and vegetables. These promising materials mainly consist of 1) extracts of bioactive compounds, 2) polysaccharides, oligosaccharides, and proteins, 3) essential oils, and 4) nanoparticles greenly synthesized by extracts. Polysaccharides, oligosaccharides, and proteins could be developed into edible coatings or biodegradable films with excellent oxygen and water barrier properties. Some extracts could be employed as immersion or washing agents to maintain the postharvest quality of fruits and vegetables and improve their resistance against diseases induced by fungal infections. Additionally, extracts, essential oils, and green synthesized nanoparticles could be incorporated into edible coatings or biodegradable films to improve their preservation effects on postharvest fruits and vegetables.