Interfacial performance of gallic acid and methyl gallate accompanied by lecithin in inhibiting bulk phase oil peroxidation

Schematic kinetic curves of the accumulation of lipid hydroperoxides (LOOH) and carbonyl compounds. PV: peroxide value; CV: carbonyl value; CMCL: the critical reverse micelle concentration of LOOH; IP: induction period; Pm: the middle point of the propagation phase; Pe: the end point of the propagation phase. [Display omitted] •Evaluation of innate potency of gallic acid and methyl gallate in donating H/e−.•Peroxidation in parallel with changes in water, interfacial tension, and particle size.•The role of interfacial activity of lecithin in the antioxidants performance.•Synergistic effect of lecithin on gallic acid and methyl gallate activities.•Lecithin as an antioxidant at lower levels than its critical micelle concentration. From an interfacial phenomena standpoint, gallic acid (GA), methyl gallate (MG), and their combination alone and together with lecithin (L) were evaluated for their inhibition against the formation of lipid hydroperoxides and carbonyl compounds in a stripped sunflower oil. Lecithin at a level (500 ppm) lower than its critical micelle concentration was able to protect the lipid system to some extent. GA (log P = –0.21), which was of higher capacity than MG (log P = – 0.14) in donating H/e− (IC50 = 36.4 vs. 39.9 μM and FRAP value = 598 vs. 514 μmol/L, respectively), exerted an antioxidant activity significantly better than MG in the bulk phase oil. Due to the improved interfacial performance, the inhibitory effect of the antioxidants was remarkably promoted in the presence of lecithin (L/GA/MG > L/GA > L/MG).