The effect of cold plasma treatment on quality attributes and shelf life of apples

Abstract

The effectiveness of atmospheric air dielectric barrier discharge (DBD) cold plasma was compared with existing decontamination methods for improving the quality and shelf life of apples. The samples were stored in two different storage conditions (ambient, 27 ± 3 °C; and cold, 10 ± 1 °C) to check the effect of storage temperature on their shelf life. The microbial load on the apples was reduced after all the treatments, and samples stored at 10 ℃ showed a higher reduction in microbial load with increased shelf life. The polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) enzyme activities showed a significant reduction after cold plasma treatment; however, peroxidase (POD) activity showed a lower reduction than PPO and PAL enzymes. Color changes evaluated using L*, a*, and b* values showed higher retention for the red color in the treated samples compared to control samples, and the firmness of all treated samples was maintained throughout the storage period. The total phenolic content (TPC) increased after cold plasma treatment and carotenoid content was retained in the treated samples. In addition, the present study demonstrated that the novel cold plasma decontamination method was more effective in reducing the pesticides (Malathion, Fenthion, and Chlorpyrifos) from the apple surfaces than the conventional methods. Cold plasma can be a better alternative for decontaminating apples; however, other hurdles may be required to increase their shelf life further.