Microbubble enhanced plasma activated oil preparation and their applications in sterilization

In this paper, plasma activated camellia seed oil (PACO) was prepared by wire to cylinder dielectric barrier discharge plasma interacted with camellia seed oil. Combined with the imaging by ICCD camera of the interaction process between plasma and camellia seed oil and the diagnosis of plasma active species by emission spectroscopy, as well as the analysis of PACO structure and physicochemical properties by Fourier transform infrared spectroscopy (FTIR) and chemical analysis, the bactericidal activity of PACO and its stability was explored. After discharging for 4 h at 16 kV and 6 kHz with He and O2 gas mixtures as carrier gas, the physiochemical properties of PACO prepared in the case by placing the plasma nozzle in the oil (PACO-4h) changed obviously. Compared with the untreated camellia seed oil, the iodine value of PACO decreased from 84.5 to $72 \mathrm{~g} / 100 \mathrm{~g}$, while the peroxide value increased from 0.5 to $64.3 \mathrm{meq} / \mathrm{kg}$ and the acid value from 2.2 to $5.5 \mathrm{mg} / \mathrm{g}$. PACO-4 h has strong bactericidal activity against E. coli and S. aureus. The diameter of bacteriostatic ring is 15.04 and 14.53 mm, respectively. Comparing of the OD600 values of PACO newly prepared with stored for 3 to 15 days, those had little change. That means the as-prepared PACO had strong bactericidal effect and good stability. According to changes of PACO OD values before and after sterilization to five common pathogens, it is easily identified that PACO has obvious bactericidal activity against P. aeruginosa, Salmonella and C. albicans besides of E. coli and S. aureus. It is of great significance for application and understanding the mechanism as well as broad-spectrum antibacterial properties of plasma activated camellia seed oil.