Increase in nitrite content and functionality of ethanolic extracts of Perilla frutescens following treatment with atmospheric pressure plasma

This study investigated the effect of atmospheric pressure plasma (APP) treatment on nitrite content and functionality of plant extracts. Ethanolic extracts of Perilla frutescens (EEP) were prepared and treated with APP for 60 min. Nitrite content increased from 0 to 45.8 mg/l in EEP after APP treatment for 60 min. Antimicrobial activity of EEP against Clostridium perfringens and Salmonella Typhimurium was increased by APP with no influence on antioxidative activity (p < 0.05). Lyophilized EEP (LEEP) treated with APP for 60 min contained 3.74 mg/g nitrite. The control (LEEP without APP) contained no nitrite. The minimum inhibitory concentration (MIC) of LEEP for C. perfringens was 200 mg/ml. The control did not inhibit C. perfringens growth between 25 and 1000 mg/ml. MICs of LEEP and the control against S. Typhimurium were 25 and 50 mu g/ml, respectively. New nitrite sources with increased antimicrobial activity can be produced from natural plants by APP treatment. (C) 2017 Elsevier Ltd. All rights reserved.