Characterizing the biological effects of sunflower oil under different ozonation levels

Ozonated vegetable oils contain oxygenated compounds formed by ozone reaction with unsaturated lipids. This study evaluated the correlation of peroxide value (PV) variations with the physicochemical, structural, antioxidant, and antimicrobial properties of ozonated sunflower oil (OSO). Ozonation increased PV (305–407 meq O₂/kg) and acid value, while reducing iodine value. Oleic and linoleic acids decreased from 36.76 to 26.57% and from 50.44 to 13.18%, respectively. Density and viscosity increased, whereas refractive index remained unchanged. Saponification value increased from 194 to 298 mg KOH/g. Color changes were evident (ΔE* = 8.14–8.44), with chroma decreasing from 12.44 to approximately 4. FTIR showed increased carbonyl and C–O vibrations from oxidative compounds. Antibacterial activity was strongest against Enterococcus faecalis and Bacillus cereus (MIC 50 mg/mL). Antifungal activity occurred against Candida glabrata, but not C. albicans. Radical-scavenging activity decreased with increasing PV, highlighting PV as an important parameter which controls OSO characteristics and optimizes potential applications.