Metal-loaded starch aerogel for ethylene adsorption under ambient conditions and its preservation of bananas

The development of materials for the control of ethylene concentration is crucial for managing fruit ripening and minimizing postharvest decay. However, commonly used ethylene removal materials, such as activated carbon and zeolite, exhibit weak affinities for ethylene, which hinders their effectiveness in adsorbing ethylene under ambient pressure. In this study, we fabricate a metal-loaded starch aerogel through the in situ reduction of metal ions on starch-fatty acid salt complexes, demonstrating enhanced ethylene adsorption properties for fruit preservation. Characterization analyses, including scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, micro-computational tomography and X-ray diffraction, revealed a porous structure with a low-density profile in the metal-loaded aerogels. These aerogels significantly surpassed the ethylene adsorption capacities of both the starch aerogel and ZSM-5 zeolite, with the nano-silver@aerogel and nano-copper@aerogel achieving the highest adsorption capacities of 30.5 mL g −1 and 32.5 mL g −1 , respectively. The materials exhibited excellent repeatable gas uptake capabilities and high stability in ethylene adsorption, which was attributed to the strong interactions facilitated by π-complexation. Theoretical calculations and X-ray photoelectron spectroscopy substantiated the π-complexation mechanism between ethylene and the metal centers through electron transfer. Preservation experiments with bananas treated with these aerogels showed that the aerogel effectively maintained fruit freshness by keeping the ethylene concentration at 0 ppm for at least 7 days. This work offers an eco-friendly and reproducible strategy for managing ethylene concentration during fruit storage and preservation, with promising applications in the food industry to reduce postharvest losses.