Integration of lipidomics and flavoromics reveals the lipid-flavor transformation mechanism of fish oil from silver carp visceral with different enzymatic hydrolysis.

Lipidomics and volatile organic compounds (VOCs) of fish oil from silver carp visceral hydrolyzed by papain, alkaline protease, pepsin, neutral protease, flavor protease, trypsin, and complex protease were investigated to explore the lipid-flavor transformation mechanism. Our results showed that diglycerol (DG, 18:4/16:1, 18:3/18:3, 16:0/18:3)/fatty acids (20:4) in glycerides and phosphatidylethanolamine (PE, 4:0/18:2)/phosphatidylglycerol (8:0e/10:3) in phospholipids could be used as markers to distinguish fish oil by different enzymolysis. A total of 130 and 36 VOCs were detected in fish oil using GC-MS and GC-IMS, respectively, including 11 key VOCs, namely 1-octen-3-ol, 1-heptanol, eugenol, (E)-2-decenal, (E, E)-2,4-heptadienal, (E, E)-2,4-decadienal, (E)-2-nonenal, benzene acetaldehyde, and 2,3-pentanedione. Moreover, the correlation analysis showed that 1-octen-3-ol, octanal, nonanal, and benzene cetaldehyde, hold significant positive correlations with the DG (16:0/18:3), DG (18:4/16:1), and PE (4:0/18:2). Conclusively, DG and PE, rich in polyunsaturated fatty acids, may be essential precursors for forming key fish oil flavors during enzymolysis extraction.