Journal of Agricultural, Life and Environmental Sciences ISSN:2233-8322(Print) 2508-870X(Online) 농업생명환경연구

Paprika is an important agricultural export in Korea. However, paprika is not suitable for exporting over long distances as it does not store well. A major cause of damage to fresh agricultural produce, including paprika, is infection with pathogenic microorganisms that cause post-harvest diseases during storage and distribution. To address this problem, research is ongoing to develop a range of surface sterilization techniques. The recent confirmation of the sterilization effects of reactive oxygen species (ROS) generated from plasma discharge has attracted substantial research interest in applying the plasma technology to agriculture. Therefore, a plasma sterilization system was developed in this study to improve paprika storability. This system consists of an atmospheric-pressure plasma generator, a plasma controller, and a chamber for plasma treatment. To validate the system performance, the internal chamber temperature was measured; the volume of ozone, a strong oxidant that generates ROS, was also measured to compute the volume of all ROS generated through plasma discharge; based on this calculation, the concentration of ROS that can effectively deactivate microorganisms was identified. The sterilization effect of the present system was examined using Erwinia carotovora, the bacteria responsible for soft rot in paprika. Erwinia carotovora samples were treated with plasma for 30 and 60 s with 2.5 bar pressure and 500 W, 700 W, and 1000 W plasma power. The samples treated for 60 s showed a 100% sterilization effect. To then validate the effectiveness of the system in maintaining paprika freshness, paprika were treated at 1000 W plasma power for 30 and 60 s. As a result, browning was observed in the stem end of untreated paprika due to withering, whereas browning was delayed for 26 d in the stem end of plasma-treated paprika.