Suppressing thermo-induced peroxidation products in peroxidatively-susceptible frying oils by the employment of culinary oil blend formulations

The consumption of highly polyunsaturated fatty acid rich (PUFA)-culinary oils is of growing concern, knowing that they are highly susceptible to thermo-oxidation, which renders them a richer source of mutagenic and cytotoxic epoxy-fatty acid and aldehydic lipid oxidation products (LOPs). To observe the effects on the resistance of PUFA-rich oils to thermo-oxidation, sunflower oil was blended with coconut and/or macadamia oils. These oil blends were continuously thermally stressed at 180 celcius, whilst undergoing stirring at 250 rpm. The chemical compositions of the thermo-oxidised culinary oils and oil blends were monitored for 300 min using high-field NMR. Analysis indicated macadamia-sunflower oil blends gave rise to a higher LOP suppressive activity than that observed with coconut-sunflower oil blends, despite coconut oil being highly saturated and therefore more highly resistant to thermo-oxidation than macadamia oil. Overall, this study highlights the practical importance in selecting the most suitable culinary oil, as well as correctly evaluating the volumetric proportional amount added for reducing the evolution of genotoxic and carcinogenic LOPs in an oil blend. It also suggests that the mechanisms by which LOP evolution can be retarded by blending requires further investigation.