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 Cu 2+ -chelated chitosan nanocrystal (Cu 2+ -ChNC), a 1D porous material, from nanocrystals of chitin, derived from fishery waste, such as shrimp and crab shells. These nanocrystals are scaffolded by Cu 2+ ions, forming a unique nanochannel structure with a diameter of about 1.5 nm. Our Cu 2+ -ChNCs have shown exceptional efficiency in absorbing common chemical residues, such as glyphosate and chlorpyrifos. Additionally, applying an aqueous Cu 2+ -ChNC suspension to fruits and vegetables significantly extends their shelf life, thanks to the antimicrobial properties of Cu 2+ ions. The synthesis process of Cu 2+ -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 Cu 2+ -ChNC is a promising material for effectively removing residues and enhancing the postharvest preservation of fruits and vegetables.