## 3 Results and Discussion  
### Texture Properties of the Gels  
The gel textures of the heat-induced and cold-induced gels are shown in Figure 1. As can be seen from Figure 1a, an increase in hardness of the heat-induced gel was observed at lower concentrations, while the gel hardness was decreased at higher concentrations of Na\({}^{+}\) (0.01-0.015 M), \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Buffer Series** & **NaCI** & **Tris-HCl, pH 8.0** & **SDS** & **Urea** & \(\beta\)**-ME** \\ \hline S1 & 0.6 mol/L & & & \\ S2 & & 20 mmol/L & & \\ S3 & & 20 mmol/L & 1\% & \\ S4 & & 20 mmol/L & 1\% & 8 mol/L & \\ S5 & & 20 mmol/L & 1\% & 8 mol/L & 2\% \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The five different buffers used to measure the solubility of the gel. Mg\({}^{2+}\) (0.01-0.015 M), and Ca2\({}^{+}\) (0.015 M). At the same concentration, Ca\({}^{2+}\) resulted in the highest gel strength. The hardness of the cold-induced gel was decreased. These results might be due to the gel strength being related to the amount of protein involved in the formation of the network structure and the forces forming the network structure [23; 24; 25]. The addition of Na+ diminishes repulsive forces, and protein-protein association occurs, forming a self-supporting gel [26]. Mg\({}^{2+}\) and Ca\({}^{2+}\) at lower levels may act as a bridge between negatively charged residues, which would promote protein aggregation with increased gel strength [27]. Additionally, excessive salt ions may result in excessive aggregation of proteins, which would decrease the gel strength. Salts at high levels might also compete for water, causing the \"salting out\" effect, with gels in turn being less soluble and weaker [28]. The strengths of gels containing Ca\({}^{2+}\) and Mg\({}^{2+}\), which had the same divalent ions, were very different. This difference resulted from dissociation of the two salts in aqueous solution. The strength of gels is affected by the type of cation [29]. Thus, the effect of Ca\({}^{2+}\) on the strength of the heat-induced gel was stronger than those of Na+ and Mg\({}^{2+}\). Figure 1: _Cont._  
Figure 1: _Cont_. The springiness and chewiness of heat-induced and cold-induced gels both increased at 0.01 M Na\({}^{+}\), 0.005 M Mg\({}^{2+}\), and 0.005 M Ca\({}^{2+}\) as shown in Figure 1b,c. Springiness measures the degree of springing back after being deformed under the first compression [21]. Chewiness signifies how much energy is needed to crunch a semi-solid food [21]. If hardness and springiness are high, it requires more mastication energy in the mouth. High springiness will be obtained when the gel structure is broken into a few large pieces during the first TPA (texture profile analysis) compression, while low springiness results from the gel breaking into many small pieces [30]. The resilience and gumminess of heat-induced and cold-induced gels both increased as shown in Figure 1d,e. Resilience is the ratio of recoverable energy when the first compression is relieved and gumminess is the product of stress at 70% compression [21; 26]. The results indicated that disulfide bonds played an important role in the network formation of heat- and cold-induced gels. Gel cohesiveness is often used as an index of the ability of a gel to maintain an intact network structure; it indicates how well the product withstands a second deformation compared to the first deformation [31]. The results showed that salt-induced aggregates of gels with different divalent and monovalent cations showed decreased cohesiveness as the concentration increased to 0.01 M, as shown in Figure 1f. The results were in good agreement with those of [PERSON], [PERSON], and [PERSON] (2009) who reported that cohesiveness was slightly decreased when the salting time was increased in salted eggs [32].