Effects of NaCl Concentration on Physicochemical Properties and Gel-forming Ability of Myofibrillar Protein from European Eel

Abstract

The effect of NaCl concentration on heat-induced gel forming ability of myofibrillar protein from European eel muscle was studied. The turbidity, surface hydrophobicity and reactive sulfhydryl groups of the protein was measured. Meanwhile, the properties of heat-induced gel of myofibrillar protein at 0.1, 0.3 and 0.5 mol/L NaCl concentration were investigated. It was found that turbidity, surface hydrophobicity and reactive sulfhydryl groups began to increase at 30, 35 and 40 ℃, respectively. With the increase of NaCl concentration, the temperature of endothermic peaks of myofibrillar protein decreased, while the storage modulus and loss modulus increased. The breaking strength of heat-induced protein gel prepared with 0.5 mol/L NaCl was 98.81 g, which was higher than that of the heat-induced protein gel prepared with low NaCl concentration. The increased NaCl concentration could promote the interaction between myosin heavy chain and actin according to the electrophoresis analysis. Based on the results of Fourier transform infrared spectra and scanning electron microscopy, heat-induced myofibrillar protein gel with 0.5 mol/L NaCl had a highest Amide II/Amide I intensity ratio and densest network. The result of this study suggested that myofibrillar protein from European eel muscle was prone to denature at above 35 ℃, and the gel strength and network structure of heat-induced myofibrillar protein gels could be improved by increasing the addition of NaCl. The obtained results will provide theoretical guidance for controlling the quality of eel based heat-processed food by using salt concentration and temperature.

Keywords

• european eel
• myofibrillar protein
• gelling properties
• heat induced gelation
• microstructure