The effect of the application of plasma-activated water (PAW) on the quality and preservation of fresh-cut lettuce is reported in this article. PAW was produced by using a liquid-cathode air discharge. The average (bulk) water temperature was kept at $\sim$ 22 $^{\circ}$ C during the activation procedure and stored at 4 $^{\circ}$ C for up to five days. The pH value, electrical conductivity, and concentrations of H $_{2}$ O $_{2}$ and NO $_{3}^{-}$ in liquid at day 1 were 2.81, 1492 $\mu$ S/cm, and 77.8 and 223.4 mg/L, respectively, with slight variations over the whole storage time. No measurable amounts of NO $_{2}^{-}$ were found. Twenty pieces of lettuce leaves were washed for 1 and 5 min in 1 L of PAW and stored for one and five days. PAW treatments were compared to tap water treatments. The lettuce samples were stored at 4 $^{\circ}$ C and analyzed on days 1, 3, and 7. The chromatic parameter results suggest that PAW treatments significantly reduce the degradation of lettuce chlorophyll from day 3 of refrigerated storage. The lettuce firmness was not significantly modified. The microbiological results of aerobic mesophilic (RAM), enterobacteriaceae, and psychrotrophs populations have shown that lettuce treated with PAW after three days of storage exhibited the strongest inactivation efficiency. Psychrotrophs counts were maintained for up to seven days. Similar inactivation efficiencies were found regardless of the PAW storage time. PAW treatments also favored both the antioxidant capacity FRAP, ABTS, and DPPH, and the total phenolic contents of lettuce at day 7 of storage.

A model of a stationary glow-type discharge in atmospheric-pressure air operated in high-gas-temperature regimes (1000 K < T_g < 6000 K), with a focus on the role of associative ionization reactions involving N(²D,²P)-excited atoms, is developed. Thermal dissociation of vibrationally excited nitrogen molecules, as well as electronic excitation from all the vibrational levels of the nitrogen molecules, is also accounted for. The calculations show that the near-threshold associative ionization reaction, N(²D) + O(³P) → NO⁺ + e, is the major ionization mechanism in air at 2500 K < T_g < 4500 K while the ionization of NO molecules by electron impact is the dominant mechanism at lower gas temperatures and the high-threshold associative ionization reaction involving ground-state atoms dominates at higher temperatures. The exoergic associative ionization reaction, N(²P) + O(³P) → NO⁺ + e, also speeds up the ionization at the highest temperature values. The vibrational excitation of the gas significantly accelerates the production of N₂(A³∑_u⁺) molecules, which in turn increases the densities of excited N(²D,²P) atoms. Because the electron energy required for the excitation of the N₂(A³∑_u⁺) state from N₂(X¹∑_g⁺, v) molecules (e.g., 6.2 eV for v = 0) is considerably lower than the ionization energy (9.27 eV) of the NO molecules, the reduced electric field begins to noticeably fall at T_g > 2500 K. The calculated plasma parameters agree with the available experimental data.