Investigation into the Differential Oxidative Regulatory Mechanisms of Lipids in Fish Oil during Thermal Oxidation in a Mixed System: The Role of Fatty Acid Saturation and Myofibrillar Proteins

Elucidating the differential oxidation of proteins and lipids is crucial for targeted flavor modulation in thermally processed fish products. This study constructed a mixed thermo-oxidation model to investigate the effects of fatty acids with different degrees of saturation (stearic acid: SA, oleic acid: OA, linoleic acid: LA) and myofibrillar proteins (MPs) on the oxidation mechanism and flavor changes of fish oil. MPs inhibited key lipid flavor precursors and double-bond volatile compounds. Co-addition of MPs with SA or LA promoted specific lipid accumulation and generated (Z)-2-decenal or (E, E)-2,4-nonadienal, respectively. Fatty acids and MPs, as free radical donors, significantly reduced triacylglycerols and sphingolipids in mackerel oil, with unsaturated fatty acids showing greater degradation. Aldehydes and ketones decreased, while alcohols and esters increased, suggesting the further oxidation of secondary flavor compounds. This study elucidated the regulatory mechanisms of fatty acids and MPs on fish oil oxidation, providing insights into flavor control in thermal processing.