Synthesis of Water Stable γ‐Cyclodextrin Metal–Organic Frameworks as a Carbon Dioxide‐Selective Layer for Preservation of Fresh‐Cut Pears by Modified Atmosphere Packaging

Abstract Modified atmosphere packaging (MAP) is widely used in the preservation of fruit, but CO 2 concentration in most MAP continues to increase because of the respiration of fruit, which causes CO 2 injury to fruit. Herein, a three‐layer composite film is prepared by using a layer‐by‐layer stacking method, with diphenyl carbonate crosslinked cyclodextrin metal–organic framework (DPC‐CL‐CD‐MOF) as the inner layer, polycaprolactone nanofiber film as the middle layer, and chitosan casting film as the outer layer. Among three layers, the DPC‐CL‐CD‐MOF layer can increase the CO 2 permeability and CO 2 /O 2 selectivity of the composite film because of its CO 2 adsorption capacity. The film exhibits moderate thermal stability but lacks mechanical strength. Gas permeability tests show that with increasing DPC‐CL‐CD‐MOF loading content from 5% to 15%, the CO 2 permeability coefficient decreases of the film from 2002.16 to 582.69 barrer. The CO 2 /O 2 selectivity peaks at 19.12 with 10% DPC‐CL‐CD‐MOF. When applied in preserving fresh‐cut pears under active MAP conditions (5% O 2 , 10% CO 2 ), the three‐layer composite film with 10% DPC‐CL‐CD‐MOF effectively prevents fresh‐cut pears from CO 2 injury, inhibiting browning and softening of pears, reducing polyphenol oxidase activity, malondialdehyde content, and hydrogen peroxide content of fresh‐cut pears.