Location: Food Quality LaboratoryTitle: An entrapped metal-organic framework system for controlled release of ethylene
|GUAN, YONGGUANG - University Of Maryland|
|TENG, ZI - University Of Maryland|
|MEI, LEI - University Of Maryland|
|ZHANG, JINGLIN - University Of Maryland|
|WANG, QIN - University Of Maryland|
|Luo, Yaguang - Sunny|
Submitted to: Journal of Colloid and Interface Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2018
Publication Date: 8/21/2018
Citation: Guan, Y., Teng, Z., Mei, L., Zhang, J., Wang, Q., Luo, Y. 2018. An entrapped metal-organic framework system for controlled release of ethylene. Journal of Colloid and Interface Science. 533:207-215.
Interpretive Summary: Non-ripe fruit such as bananas that will ripen after harvest when treated with the natural ripening agent ethylene are classified as climacteric fruit. Treating climacteric fruits with ethylene gas to stimulate ripening is a common industry practice. While this process ensures best eating quality of the fruits, the flammable nature of ethylene restricts such applications to only skilled workers at specially designed facilities. More importantly, ethylene application shortens product shelf life especially when the ripened fruits cannot be consumed within the short period following the treatments. In collaboration with a university partner, USDA scientists developed a novel storage system comprising a core for safe ethylene storage and a shell for controllable release. This technology offers consumers, shippers, and other fresh produce handlers an option to treat climacteric fruits at the end of the supply chain, making high quality ripe fruit available as needed, and minimizing postharvest loss and waste.
Technical Abstract: A novel gas storage and release system was developed for ethylene, an exogenous plant hormone that regulates fruit ripening and senescence. This system consists of a metal organic framework (MOF) core and an alginate-based shell. The MOF comprises a coordination complex of Al and [btc]3- ligands, which formed hexagonal structure (P63/mmc) with unit cell of 14.28 × 14.28 × 31.32 Å3, as revealed by the X-ray diffraction analysis. Ethylene absorption isotherm exhibited an absorption capacity of 41.0 cm3/g MOF at 25 °C and 101.3 kPa. After charging with ethylene, the MOFs are further entrapped in a close-knit bead formed with alginate-Fe(III) matrix, observed under a scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). The alginate shell is degraded by exposing to 200 mM sodium citrate (NaCit) aqueous solution, triggering a continuous release of ethylene. With 50 mg of MOF, ethylene concentration reached 0.164-0.182 mg/L after 2.5 hr. This is the first report regarding a controlled release of ethylene through degrading alginate-Fe(III) matrix rather than by changing the interfacial pore size of Al-MOF at extreme conditions. This technology can enable precisely controlled and targeted applications of ethylene for food processing and agricultural applications.