Partial NaCl replacement with arginine during brining influences apoptosis and post-brining quality of grass carp...

Traditional salt brining may compromise the biochemical stability and texture of fish fillets during storage. This study evaluated the effects of partial sodium chloride substitution with arginine on postmortem quality and apoptosis in grass carp fillets. Fillets were treated with NaCl, arginine, or their mixtures, rinsed, and stored at 4 °C. The 1.5% NaCl + 1.5% Arg treatment delayed ATP degradation, reduced K-values, and improved color retention. Apoptosis-related markers, including caspase-3 activity and inducible nitric oxide synthase (iNOS) expression, increased during brining and remained elevated during storage in high-NaCl and high-Arg groups. Immunofluorescence confirmed sustained iNOS-associated apoptotic activity under these conditions. In contrast, balanced substitution attenuated oxidation-related indices and coincided with lower caspase-3 activity and reduced TUNEL/iNOS signals during storage. These findings suggest that NaCl-arginine brining alters oxidative and apoptosis-associated responses, thereby delaying quality deterioration during chilled storage.