Dielectric barrier discharge enhances ethylene decomposition and delays tomato fruit ripening during storage by cold atmospheric plasma

Abstract

Although the application of cold atmospheric plasma (CAP) technology in the preservation of fruits has attracted much attention, the effect is limited because CAP generator is commonly designed to reduce microbial contaminations, instead of destroy ethylene. This work was aimed to develop a dielectric barrier discharge (DBD) technique to generate CAP, directly based on the evaluation of the effects of different discharge factors of DBD device on the decomposition of ethylene. The results showed that CAP (quantitatively indicated with ozone and nitrogen oxides) was rapidly generated and ethylene was effectively decomposed by the existing DBD reaction device, with discharge voltage 25 kV, input frequency 8 kHz, electrode gap 4 mm, dielectric thickness 2 mm, and equipped with a heat-resistant ceramic plate used as the dielectric material under normal atmospheric conditions. The decomposition rate of ethylene reached more than 90 % after 4 min of treatment with CAP generated by DBD, and completely 100 % after 6 min, whether high or low initial concentration of ethylene at the beginning of CAP generation. Moreover, the CAP treatments both high- and low- intensity generated by the DBD device effectively suppressed ethylene production, delayed the color change of green ripe tomatoes and the decrease in fruit hardness during storage. In conclusion, the optimization of the design of DBD device according to its capacity of decomposing ethylene provided an alternative approach to enhance effect of CAP on fruit preservation.