Abstract: The objective of this study was to evaluate the effect of different concentrations of NaCl (0.1, 0.2, 0.3, 0.4, 0.5, and 0.6 mol/L) on the properties of turbot myofibrillar protein (MP). MP was extracted and its solubility, emulsifying properties, chemical interactions (ionic bonds, hydrogen bonds and hydrophobic interactions) and sulfydryl contents, secondary structures and rheological properties were measured. The results showed that solubility, emulsifying activity index (EAI), emulsion stability index (ESI), active and total sulfydryl contents increased with the increase in NaCl concentration. Meanwhile, ionic and hydrogen bonds first increased and then decreased, whereas hydrophobic interactions first decreased and then increased. The secondary structures of MP tended to transit from helix to sheet with no significant change being observed for the other secondary structures; storage modulus (G’) was increased, with the highest value being observed at a NaCl concentration of 0.6 mol/L. In summary, 0.6 mol/L NaCl was optimal for improving the properties of turbot myofibrillar protein.

Key words: turbot, myofibrillar protein, NaCl, secondary structure, rheological properties