Oxidation mechanism and interrelationship of lipid and protein oxidation in duck leg muscles during sous vide cooking

The laws and interrelationships of lipid and protein oxidation in duck meat during sous vide cooking (SVC) are still unclear. In this study, the oxidation mechanisms of the muscle of duck legs during SVC were investigated from the aspects of fatty acid (FA) profile, antioxidant system activity, enzyme activity, and iron element. Lipid oxidation predominantly occurred within the initial 0-2 h of the SVC process, during which the Thiobarbituric acid reactive substances (TBARS) value escalated to 10-fold of its initial level. Protein oxidation was mainly observed between 0 and 4 h, with the carbonyl content increasing by 23.3%. The FAs profile underwent changes primarily within the initial 0-2 h, and then their proportions continued to evolve in a manner that was favorable for oxidative stability. Following 4 h of SVC, the scavenging rates of ·OH and DPPH· free radicals decreased to the lowest, decreasing by 92.9% and 45.6%. As cooking time increased, lipoxygenase activity increased by more than six times, while Total superoxide dismutase (T-SOD) and GSH-Px activity decreased by 31.7% and 75.2%, respectively. The heme iron content was decreased by 26.1% after 8 h of SV treatment. These data can provide a theoretical foundation for optimizing parameters of the SVC process and improving the oxidative stability of SVC meat products.