Effect of ionic strength on the structural properties and emulsion characteristics of myofibrillar proteins from hairtail (Trichiurus haumela)

Myofibrillar proteins (MPs) are susceptibly affected by ionic strength. The effect of ionic strength on the structure and emulsifying properties of MPs from hairtail (Trichiurus haumela) is still unclear. Therefore, the effect of ionic strength on the structural properties and emulsification of myofibrillar proteins from hairtail was analyzed. The increase in ionic strength led to the increase in endogenous fluorescence intensity of MPs. The alpha-helix content in MPs first increased and then decreased from ionic strength of 0 to 1.0 mol/L and beta-sheet content exhibited the oppositive trend, indicating that alpha-helix in MP transformed into beta-sheet. The surface hydrophobic groups of MPs increased; however, the contact angle decreased with the increase in ionic strength of 0-0.8 mol/L and a slight rebound at 1.0 mol/L. Sulfhydryl content and electrophoretic analysis further exhibited the change of MP structure at ionic strengths of 0-1.0 mol/L. Besides, the droplet size of MP emulsions was small and evenly distributed at 0.6 mol/L. Additionally, the creaming index of MP emulsions had better stability prepared at 0.6 mol/L than the other ionic strength conditions. The apparent viscosity of MP emulsions increased with the increase in ionic strength of 0-0.8 mol/L and decreased slightly at 1.0 mol/L. The rheological behavior of MP emulsions exhibited gel-like behavior without the effect of temperatures at 20-80 C. These results can broaden the potential application of MPs from hairtail on the emulsion-type seafood products and delivery system in the food industry.

Automated summary

This study investigated the effects of ionic strength on the structure and emulsifying properties of myofibrillar proteins from hairtail. The results showed that the increase in ionic strength caused changes in the structure and emulsification of the proteins. These findings have significant implications for the application of myofibrillar proteins in emulsion-type seafood products and the food industry.