Construction of fatty acid-conjugated antioxidant peptides and their thermostabilizing effects on flaxseed oil

Natural peptide antioxidants often face challenges of poor stability and limited efficacy in lipid systems. To address these constraints, we engineered C8-ED by conjugating octanoic acid to the ED dipeptide. Structural characterization revealed C8-ED's transformation into fibrous tubular aggregates. The modified peptide concurrently demonstrated enhanced antioxidant capacity, with superoxide scavenging reaching 45.9 % (vs. 11.3 % control) and linoleic acid oxidation inhibition of 63.9 % (vs. 27.3 % control). In flaxseed oil at 240 °C, C8-ED reduced peroxide value to 25.1 meq kg −1 (vs. 34.1 meq kg −1 control) and minimized viscosity elevation, outperforming control and TBHQ respectively in oxidation suppression. This work establishes a peptide design principle where fatty acid conjugation and sequence compatibility synergistically enhance thermal stability, providing a biomolecular strategy for developing multifunctional lipid protectants in high-temperature food applications. • C8-ED exhibits thermal stability and dual antioxidant-lipid protection functions. • C8-ED achieves 45.87 % superoxide scavenging efficiency, surpassing ED's 11.26 %. • C8-ED forms enzyme-resistant gels, reducing flaxseed oil oxidation by 26.5 % at 240 °C. • C8-ED outperforms TBHQ in high-temperature oxidation resistance.