Effect of triacylglycerol structure on the antioxidant activity of γ-oryzanol

[Display omitted] •γ-Oryzanol activity in the propagation phase was determined using a Sigmoidal model.•Removal of TAG structure (RTS) increased the antioxidant activity of γ-oryzanol.•ET mechanism showed an important effect on improving the γ-oryzanol performance.•Mass transfer of reactants was facilitated by RTS.•RTS improved the effective collisions between γ-oryzanol molecules & free radicals. In this study, the triacylglycerol structure of vegetable oils was removed and the effects of this removal were observed on the antioxidant efficiency of γ-oryzanol. A sigmoidal-model was used for calculating kinetic parameters relevant to the initiation and propagation phases during the peroxidation of soybean, corn, sesame, and olive oils as well as their fatty acid methyl esters. Removing the triacylglycerol structure caused an increase in the antioxidant activity of γ-oryzanol (26.49%) by affecting both inhibitory mechanisms, i.e. hydrogen-donating (7.80%) and electron-transfer (14.72%). Unexpectedly, the antioxidant performance of γ-oryzanol continued even when the induction period had ended. During the propagation phase, the highest antioxidant activity was observed in the fatty acid methyl esters of soybean oil (3.86) based on hydroperoxides decomposition. An evaluation of how the endergonic activated complexes formed could indicate that the removal of the triacylglycerol structure increased the effective collisions between the γ-oryzanol molecules and free radicals.