Abstract

The present study compares the efficacy of plasma-activated water (PAW) produced by dielectric barrier discharge (DBD) and microwave (MW) plasma for extending fruit shelf life and enhancing seed germination and plant growth. PAW was generated using both DBD and MW setups, and their physicochemical properties have been analyzed. DBD-PAW exhibited a higher oxidizing potential, with an oxidation–reduction potential (ORP) of 647 mV compared to 427 mV for MW-PAW, the higher value of ORP in DBD-PAW was due to the presence of hydrogen peroxide (18.9 mg L⁻¹) and dissolved ozone (2.3 mg L⁻¹). In contrast, MW-PAW had higher electrical conductivity and contained greater concentrations of nitrogen species, such as NO<inf>2</inf>ˉ and NO<inf>3</inf>ˉ; this was attributed to the higher emission band peaks of NO<inf>γ</inf> in the MW plasma compared to the DBD plasma, leading to an increased concentration of dissolved NO<inf>2</inf>ˉ and NO<inf>3</inf>ˉ ions in PAW. Additionally, the elevated temperature of the MW plasma inhibited the formation of H<inf>2</inf>O<inf>2</inf> and O<inf>3</inf> in the PAW. In food preservation trials, DBD-PAW significantly reduced microbial growth, spoilage, and weight loss in lemons and chilies compared to MW-PAW, achieving a 54.7% microbial reduction in lemons and 58% in chilies, with nearly no spoilage after two weeks, while MW-PAW-treated fruits exhibited 23–24% spoilage. DBD-PAW also enhanced seed germination by degrading the hydrophobic seed coat. However, in plant growth trials, MW-PAW was more effective, promoting root lengths that were 18.4% longer and shoot lengths 56.8% longer, along with higher fresh and dry weights. In conclusion, DBD-PAW is more effective for food preservation, while MW-PAW promotes superior plant growth, offering complementary benefits for sustainable agriculture and food storage.