Ion-chelated porous chitosan nanocrystal for highly efficient postharvest preservation

The presence of pesticide and herbicide residues on fruits and vegetables poses significant health risks, making it a major concern for consumers worldwide. We engineered Cu2+-chelated chitosan nanocrystal (Cu2+-ChNC), a 1D porous material, from nanocrystals of chitin, derived from fishery waste, such as shrimp and crab shells. These nanocrystals are scaffolded by Cu2+ ions, forming a unique nanochannel structure with a diameter of about 1.5 nm. Our Cu2+-ChNCs have shown exceptional efficiency in absorbing common chemical residues, such as glyphosate and chlorpyrifos. Additionally, applying an aqueous Cu2+-ChNC suspension to fruits and vegetables significantly extends their shelf life, thanks to the antimicrobial properties of Cu2+ ions. The synthesis process of Cu2+-ChNC is scalable, and the full process only employs materials and chemicals recognized as safe in food by the US Food and Drug Administration (FDA). Our research indicates that Cu2+-ChNC is a promising material for effectively removing residues and enhancing the postharvest preservation of fruits and vegetables.