Abstract: This study aimed to elucidate the mechanism of lipid oxidation in different parts of silver carp during the drying process. The dorsal and ventral muscles of this fish, which differ significantly in lipid composition, were dried at 45 ℃ for up to 48 h. Their peroxide values (POV), thiobarbituric acid reactive substances (TBARS) values, free fatty acid (FFA) composition, sensory properties, and volatile flavor compounds were measured during the drying process. Moreover, the correlations among POV, TBARS values, FFA composition, and volatile flavor compounds were analyzed. The results showed that the POV and TBARS values of the dorsal muscle increased significantly during drying, especially in the middle and late stages (24–48 h), reaching (12.49 ± 1.01) mmol/kg and (1.73 ± 0.55) mg/kg, respectively, while the oxidation process of the dorsal muscle was relatively mild. The ventral muscle accumulated higher concentrations of (E)-2-nonenal, 1-octen-3-ol, hexanal, 2-pentylfuran and heptanal (OAV > 1) at the end of drying (48 h) and showed the most prominent rancid and oily notes in sensory evaluation, while the dorsal muscle displayed the strongest meaty aroma and the most balanced flavor profile at 48 h. Correlation analysis indicated that key fishy odor compounds such as hexanal, heptanal, and (E)-2-nonenal were significantly negatively correlated with polyunsaturated fatty acids including linoleic acid, alpha-linolenic acid, arachidonic acid, and docosahexaenoic acid (DHA). In conclusion, the dorsal and ventral muscles of silver carp exhibit distinct oxidation pathways and flavor evolution patterns during drying, providing a theoretical basis for the optimization of part-based processing technologies for fish products and the development of distinctive differentiated dried fish products.

Key words: oxidation; flavor; precursor; drying