New perspectives on the ozonated high-oleic sunflower oil physico-chemical behaviour

Despite high-oleic sunflower oil (SFO) having strong antioxidant properties, there are very few studies regarding its physico-chemical characterization. In this study, SFO obtained through cold pressing, without prior chemical treatment, was subjected to an ozonation process. Simultaneously, a water-SFO emulsion (1:9 ratio) was prepared and ozonated in the same conditions. Both ozonated samples underwent physico-chemical evaluation (acid and peroxide values (AV, PV), rheological behaviour), structural analyses, and antioxidant properties evaluation. Through their AV and PV, the samples demonstrate excellent stability over time, from an AV of 3.073 to 3.723 mg NaOH/g oil and from a PV of 1439.36 to 1645.29 mmol/equiv/g oil over 6 months storage for ozonated SFO. The viscosity and flow activation energy increase with ozonation time and are superior to those of raw oil. The NMR and FTIR analyses reveal a high ozonation degree over time, acting according to Criegee's mechanism, and the water presence accelerates the ozonation process. Both sample types exhibited a strong capacity to neutralize free radicals, a high affinity for binding Fe²⁺ ions, and remarkable efficacy in protecting lipid membranes. The results obtained in our study bring important high novelty contributions in the field of ozonated sunflower oils, make it a promising candidate for future in-vivo testing.