Methionine sulfone-containing orbitides, good indicators to evaluate oxidation process of flaxseed oil

This study aimed to explore the possibility of using methionine sulfone (Msn)-containing orbitides as indicators to evaluate the oxidation process of flaxseed oils. Results showed that after 4 days' heating, oxidation values slightly increased (p > .05) with significant decrease in methionine (Met)-containing peptides (p < .05) instead of γ-tocopherol (p > .05). However, as oxidation time continues increasing, oxidation values significantly increased (p < .05) with significant reduction of γ-tocopherol (p < .05). It demonstrated that Met-containing peptides were more readily oxidized compared with γ-tocopherol and showed certain antioxidant activity. Besides, high logarithmic correlations were found between oxidation values and Msn-containing orbitides (0.94-1.00), such as between total carbonyl compounds and orbitide [1-8-NαC],[1-MetO2]-CLE (64.95 lnx − 52.14, R2 = 0.99, Dingya23 oil). Therefore, in comparison with common oxidation indices, Msn-containing orbitides may be better indicators for evaluating the oxidation process of flaxseed oil with superior separation efficiency, specific information and high stability.