Abstract

This study evaluated the effectiveness of plasma-activated water (PAW) for preserving Cestrum nocturnum L. (Night-Blooming Jasmine, NBJ) flowers when applied as either a washing treatment or a storage medium. Plasma treatment for 10–30 min progressively altered water properties (PAW-10 to PAW-30); after 30 min, pH decreased from 6.9 to 4.9 and oxidation potential increased from 250 to 385 mV. Electrical conductivity increased to 170 from 1 µS cm⁻¹, respectively, while NO<inf>3</inf>^- and NO<inf>2</inf>⁻ concentrations reached 13.8 and 1.4 mg L⁻¹. H<inf>2</inf>O<inf>2</inf> and dissolved O<inf>3</inf> initially increased but subsequently declined due to reactive interactions under acidic and highly oxidative conditions. PAW washing significantly improved postharvest quality such as minimizes weight loss, microbial growth, spoilage, and sensory attributes. After 15 days, normalized microbial growth was reduced to 0.71, 0.61, and 0.66 for PAW-10, PAW-20, and PAW-30, compared to control. Final weight loss decreased to 25.3% (PAW-10), 20.9% (PAW-20), and 23.9% (PAW-30), compared with higher losses in the control. Spoilage was also reduced from 100% in the control to 73%, 85%, and 92% in PAW-10, PAW-20, and PAW-30 treatments. Nonetheless, PAW-washed flowers exhibit brighter colors and a slower browning process, along with sustained antioxidant properties. In contrast, using PAW as a storage medium did not effectively limit spoilage and may have induced oxidative damage due to prolonged exposure to reactive species. Overall, PAW is effective as a washing agent to enhance flower quality, although its direct use as a storage medium requires caution.