Blueberry Extract as a Source of Natural Antioxidants to Improve Thermal Stability of Standard Sunflower Oil

Vegetable oils are highly susceptible to thermo-oxidative degradation, leading to the deterioration of quality, the development of undesirable off-flavours, and the generation of potentially harmful compounds that may pose risks to human health. Although synthetic antioxidants are commonly used to mitigate these effects, growing safety concerns have stimulated research interest in natural alternatives. In the present study, a selection of commercially available plant extracts were carefully chosen and evaluated to assess their efficacy in enhancing the thermal oxidative stability of standard sunflower oil. Among the extracts tested, one blueberry extract (BE-B) exhibited the highest phenolic content as well as the strongest antioxidant activity. When incorporated into oil, BE-B significantly delayed the formation of primary oxidation products and the development of triacylglycerol polymers during heating, with the protective effects becoming more pronounced at higher concentrations. Volatile compound analysis further confirmed a substantial reduction in α,β-unsaturated aldehydes, which are recognized as major contributors to rancidity and oil degradation. Overall, these findings indicate that BE-B represents a highly promising natural antioxidant, capable of improving the quality and stability of vegetable oils, and underscore the potential for blueberry extract to be employed in commercial applications within the edible oil industry.