Potential of metal-organic frameworks to adsorb ethylene for fresh produce active packaging applications

Metal-organic framework (MOF) is an innovative synthetic porous material widely used for gas storage and separation, but its applications for food packaging have barely been investigated. The objective was to evaluate MOFs' potential to be embedded in packaging films as ethylene adsorbers to control ripening and extend the shelf life of fresh produce during distribution. The potential was evaluated at two levels. The first evaluation was at the MOF powder level, where the ethylene adsorption capacities of eight commercial MOF powders were measured using gas chromatography (GC). As a result, Mg formate MOF (MgF) and Al(OH) fumarate MOF (AlF) were found to have much higher ethylene adsorption capacities than the other six MOFs. Overall, MgF was the best ethylene adsorber due to its stable ethylene adsorption under various temperatures, relative humidities, and ethylene concentrations. The second evaluation was at the packaging film level, where MgF powder was embedded into three different packaging films. The results showed that MgF-embedded LDPE film had higher ethylene adsorption than MgF-embedded PLA and PVA films. Furthermore, a bio-efficacy study confirmed that MgF-embedded LDPE film could effectively delay banana ripening and extended their shelf life. In conclusion, this study indicates that MgF has promising potential as an ethylene adsorber for shelf life extension of bananas and probably other fresh produce.