Salting-induced lipid hydrolysis and oxidation in dried squid fillets: A mechanistic link to formaldehyde formation, color browning, and flavor alteration.

Salt-dried squid fillets (SDSF) is a popular seafood product. In this study, the effect of different NaCl concentrations (0 %, 1 %, 5 % and 10 %) on the color, formaldehyde (FA) and volatile compounds (VOCs) of SDSF was investigated by determining the acid value (AV), thiobarbituric acid reactive substances (TBARS) value, lipid-related enzyme activities and lipidomics. These findings showed that the AV and TBARS value initially increased and subsequently decreased with increasing NaCl concentrations. Lipidomics indicated salting facilitated the hydrolysis of triglycerides and phospholipids by lipase, alongside the oxidation of fatty acids by auto-oxidation and lipoxygenase. Specifically, salting darkened the color via pyrrolization and inhibited the FA content via alleviating lipid oxidation, and contributed to characteristic VOCs (3-methyl-butanal, methionaland nonanal, etc.). Overall, 5 % NaCl SDSF performed less browning and FA content (23.95 mg/kg), but more VOCs (2885.03 μg/kg) and better overall acceptance. This research contributes to improving the quality of salt-dried seafood.