Ion-chelated porous chitosan nanocrystal for highly efficient postharvest preservation

Abstract

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.