Increasing the oxidative stability of soybean oil through fortification with antioxidants

Vegetable oils high in polyunsaturated fatty acids (PUFA), like soybean oil (SO), are known for lowering the risk of consumers for contracting cardiovascular disease as well as improving cognitive health. However, they are more susceptible to lipid oxidation than recently introduced high-oleic cultivars like high-oleic sunflower oil (HOSFO). Thus, the objective of this study was to increase the stability of PUFA oils to maintain the aforementioned health benefits by supplementing them with industrially relevant antioxidant compounds that prevent or delay oxidation during food production and storage. Herein, a variety of synthetic and natural antioxidants tested alone or in mixtures was screened to bring the stability of SO closer to that of HOSFO. Oils were stored under accelerated conditions (35 °C) in the dark for 28 weeks, and the evolution of primary (hydroperoxides) and secondary (hexanal) lipid oxidation products was monitored. Oxidative stability index data showed that addition of 300 ppm of ascorbyl palmitate (AP) stabilised SO to the greatest magnitude. Further, a combination of AP (300 ppm) and M-TOC (1000 ppm) was able to limit hydroperoxide and hexanal formation in SO at 35 °C for 12 weeks. It was demonstrated that assessing multiple quality parameters for lipid stability are a necessary undertaking.