Effect of the different levels of salt and phosphate on some emulsion attributes of the northern pike fish (Esox lucius L., 1758) flesh

Abstract

In this present study, the effect of salt (NaCl) (0.0, 1.0, and 2.0%) and phosphate (K2HPO4) (0.00, 0.25, 0.50%) solutions at various concentration on the emulsion properties of Northern pike fish flesh was studied in a model system. Protein, fat, ash, dry matter contents of Northern pike flesh (pH 6.7) were 16.83, 2.41, 0.82, and 20.16%, respectively. pH values of slurries containing fish flesh, salt and phosphate solutions ranged from 6.58 to 7.30. Emulsions prepared with various slurries had pH values ranging from 6.81 to 7.87. The emulsion or slurry pH values significantly increased with the use of phosphate solution (p<0.01). On the other hand, the effect of salt was insignificant (p>0.01), even though the use of salt concentration decreased pH values of either slurry or emulsion. Emulsion capacity (EC) of Northern pike fish varied from 230.74 to 274.44 mL oil/g protein. The use of phosphate solution significantly increased EC (p<.01). However, the effect of salt concentration on EC was insignificant (p>0.01). Emulsion stability (ES) was between 66.00 and 78.97%. The increase in phosphate concentration or the presence of salt in emulsion increased ES values (p<0.01); however, salt concentration had an insignificant effect on ES (p>0.01). Emulsion viscosity (EV) values ranged from 1800 to 4600mPa. s. While all phosphate treatments increased EV values significantly (p<0.01), the effect of salt was statistically insignificant (p>0.01). In conclusion, Northern pike fish is suitable for emulsion type of food products as far as its emulsion properties are concerned. Moreover, the combination of salt and phosphate solutions with fish flesh may be helpful for further improvement of its emulsion properties.