Comparison of the Changes in Fatty Acids and Triacylglycerols between Decapterus maruadsi and Trichiurus lepturus during Salt-dried Process

In order to reveal changes in fatty acids and triglycerides during the pickling process of white-fleshed and dark-fleshed fish with high-fat, to compare the changes of triacylglycerols (TAGs) and fatty acids (FAs) in round scad (Decapterus maruadsi, dark-fleshed) and hairtail (Trichiurus lepturus, white-fleshed) during salt-dried processing, ESI-MS/MS and GC-MS techniques were used to quantify. Lipid oxidation was evaluated via peroxide values (POVs), and thiobarbituric reactive substances (TBARS). A total of 31 and 27 FAs, 45 and 44 TAGs were quantified in round scad and hairtail, respectively. DHA (C22:6n3), palmitic acid (C16:0), stearic acid (C18:0), and oleic acid (C18:1n9) were the main FAs in round scad. POO (16:0/18:1/18:1), PPO (16:0/16:0/18:1), POD (16:0/18:1/22:6), and PPaO (16:0/16:1/18:1) were dominant TAGs in both species. Salt-dried processing significantly affected (p < 0.001) 7/5 FAs and 24/29 TAGs in round scad/hairtail. MUFAs changed significantly (p < 0.05) in dark-fleshed round scad; only SFAs and PUFAs changed in white-fleshed hairtail. Both species exhibited near-identical TAG compositions with different variation trends. More significant changes were observed in FAs at the half-dried stages and in TAGs (p < 0.05) at the salted stage. This coincided with the changing stages of POV and TBARS values that also increased significantly (p < 0.05) at the salted stages but peaked at the half-dried stages of both species.