Impact of Micelle-Mediated Mass Transport of Oxidation Products on the Stability of Flaxseed Oil Emulsions

The physicochemical stability of emulsions is critically influenced by the aqueous phase micelle‑mediated dynamic transport of oxidation products. In this study, the dynamic migration of lipid oxidation products was investigated in flaxseed oil emulsions stabilized by five surfactants- Tween 20 (T20), sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), saponin (QS), and phospholipid (PL). Initial droplet sizes ranged from 0.15 to 0.29 µm, with SDS- and CTAB-stabilized emulsions exhibiting superior physical stability (TSI < 1.5) throughout storage. PL and QS generated highly viscous, polar interfaces that sterically impeded reactant diffusion, restricting aqueous phase lipid hydroperoxide (LOOH) concentrations to 6.56 and 5.50 µmol/L, respectively. Conversely, SDS and CTAB formed low-viscosity, highly fluid films that accelerated mass transport, with CTAB micelles exhibiting a propensity to transfer lower-molecular-weight secondary oxidation products, such as malondialdehyde (MDA, 3.46 µmol/L). Notably, T20 micelles facilitated the partitioning of LOOH into the aqueous phase (up to 23.95 µmol/L), spatially isolating these primary products from the oxidation sites. The above partitioning delayed the further degradation of LOOH, resulting in a slow increase in emulsion TBARS content (0.28–1.32 mmol/kg oil). By correlating interfacial structure with micelle-driven mass transfer, this work provides a theoretical basis for stabilizing flaxseed oil emulsions rich in n-3 polyunsaturated fatty acids.