Air Atmospheric Pressure Plasma Jet to Improve Fruiting Body Production and Enhance Bioactive Phytochemicals from Mutant Cordyceps militaris (White Cordyceps militaris)

This article investigated the effects of an air atmospheric pressure plasma jet (APPJ) with different treatment times (30 to 120 s) on changes in fruiting body production and biochemical phytochemicals from white Cordyceps militaris (white C. militaris). A low-cost neon transformer was applied to generate the APPJ. An optical emission spectrometer revealed reactive species, including hydroxyl radicals, nitrogen oxide, and atomic oxygen. After treatment with the optimal APPJ conditions, the fresh and dry weights of white C. militaris fruiting bodies significantly increased by 56.7 and 55.4%, respectively. Higher values of cordycepin, adenosine, superoxide dismutase, glutathione S-transferase, and beta-glucan in white C. militaris fruiting bodies were observed after a short time of APPJ treatments. Higher malondialdehyde contents were determined to be associated with high concentrations of APPJ treatments. However, the contents of carotenoids degraded with APPJ treatment. In addition, APPJ treatments significantly enhanced the total phenolic content, flavonoid content, polysaccharide content, 2,2-diphenyl-1-picrylhydrazyl radical scavenging ability, and ferric reducing antioxidant power. Thus, these results suggested that APPJ treatment improves the fruiting body production and nutritional qualities of white C. militaris, which provide health benefits for humans.