Effects of Reverse Micelles Formed by Minor Components on Oxidative Stability of Flaxseed Oil

In this research, the critical micelle concentrations (CMC) of various minor components (phospholipids, oleic acid, β-sitosterol and diglyceride (DAG)) in stripped flaxseed oil were determined, and the effects of the formation of reverse micelles on the oxidative stability of the flaxseed oil and the antioxidant activity of α-tocopherols were studied. The results showed that phospholipid (DOPC) was an important component for the formation of reverse micelles, and its critical micelle concentration was 125 μmol/kg oil. Compared with the control group, the addition of low concentrations (< CMC) of microcomponents had no significant effect on the thermal stability of flaxseed oil. But the formation of reverse micelles could reduce the initial oxidation temperature (~12%) and oxidation induction time (~33%) of the oil, and increase the concentrations of hydroperoxide (~36%), propionaldehyde (~13%) and hexanal (~200%) during storage, showing pro-oxidant activity. Compared with the control group, α-tocopherol inhibited the oxidation of oil, but the formation of reverse micelles exhibited higher oxidation product concentration, reducing the antioxidant activity of α-tocopherol. Therefore, controlling the formation of reverse micelles in flaxseed oil is beneficial to improve its oxidative stability, and can provide a new strategy and approach for the steady-state control of oil rich in n-3 polyunsaturated fatty acids (PUFA).