## 3 Results and Discussion
### Color Analysis  
The whiteness of pangasius gel at different pressure treatments and salt concentrations is shown in Table 1. PG gels exhibited whiteness values ranging from 63.17 \(\pm\) 0.26 to 64.56 \(\pm\) 2.04 and were higher than those of HIGs (60.52 \(\pm\) 0.10) (_p_ < 0.05). This result corresponds with the study by [PERSON] et al. (2015) [5] on Alaska Pollock gel in which brightness increased with higher pressure levels. It is hypothesized that HPP can induce greater protein denaturation, aggregation, and cross-linking, resulting in structural changes in a way that increases whiteness [4; 5]. In addition, HPP may disrupt the heme group and break down globin in fish muscle proteins, reducing pigment intensity and enhancing the whiteness of fish gels [33]. It has been suggested that the increase in light scattering due to compact protein structures and the formation of a homogenous gel matrix also enhances the brightness [34]. In this study, all HPP-treated samples showed significantly increased whiteness regardless of salt concentration and pressure level, as compared to HIGs, which could be caused by protein structure changes and pigment disruption. This result also aligns with other research reporting that pressures above 200 MPa significantly altered the color of white fish meat [35]. Figure 1: TPC of pangasius gels at 1% and 2% salt concentrations at different high-pressure processing conditions. HIGs: conventional heat-induced gels; PG300/1%: salt concentration 1% and 300 MPa/10 \({}^{\circ}\)C/10 min; PG300/2%: salt concentration 1% and 300 MPa/10 \({}^{\circ}\)C/10 min; PG400/1%: salt concentration 1% and 400 MPa/10 \({}^{\circ}\)C/10 min; PG400/2%: salt concentration 1% and 400 MPa/10 \({}^{\circ}\)C/10 min; PG500/1%: salt concentration 1% and 500 MPa/10 \({}^{\circ}\)C/10 min; PG500/2%: salt concentration 1% and 500 MPa/10 \({}^{\circ}\)C/10 min. Different letters (a–c) indicate significant differences (_p_ < 0.05). \(\Delta\)E represents the perceptual difference in color between fish samples, with higher \(\Delta\)E values indicating a greater color difference [23]. \(\Delta\)E values ranging from 3.0 to 6.0 correspond to very distinctive differences, while \(\Delta\)E values ranging from 6.0 to 12 indicate strong differences [36]. In this study, the \(\Delta\)E value ranging from 6.15 to 6.59 indicates a strong color difference between the pressure-induced gels and HIGs (Figure 2). These results confirm that HPP changed the appearance of pangasius gels compared to HIGs in both statistically and visually significant ways. The effect was apparent at both 1% and 2% salt concentrations, suggesting that pressure treatment resulted in dominant effects on gel color as compared to salt concentration. \begin{table}
\begin{tabular}{c c c} \hline
**Treatment** & **Whiteness** & \(\Delta\)**E** \\ \hline HIGs & 61.21 \(\pm\) 0.55a & \\ PG300/1\% salt & 64.56 \(\pm\) 2.04b & 6.53 \(\pm\) 0.88 \\ PG300/2\% salt & 63.17 \(\pm\) 0.26b & 6.15 \(\pm\) 0.99 \\ PG400/1\% salt & 63.45 \(\pm\) 0.91b & 6.59 \(\pm\) 0.47 \\ PG400/2\% salt & 64.06 \(\pm\) 0.50b & 6.18 \(\pm\) 0.71 \\ PG500/1\% salt & 63.81 \(\pm\) 1.43b & 6.42 \(\pm\) 0.59 \\ PG500/2\% salt & 63.26 \(\pm\) 0.67b & 6.54 \(\pm\) 0.49 \\ \hline HIGs: conventional heat-induced gels; PG300/1\%: salt concentration 1% and 300 MPa/10 \({}^{\circ}\)C/10 min; PG300/2\%: salt concentration 1% and 300 MPa/10 \({}^{\circ}\)C/10 min; PG400/1\%: salt concentration 1% and 400 MPa/10 \({}^{\circ}\)C/10 min; PG500/1\%: salt concentration 1% and 500 MPa/10 \({}^{\circ}\)C/10 min; PG500/2\%: salt concentration 1% and 500 MPa/10 \({}^{\circ}\)C/10 min. Different letters (a, b) in the same column indicate significant differences (\(p<0.05\)). & \\ \hline \end{tabular}
\end{table} 
Table 1: Color of pangasius gel at 1% and 2% salt concentrations under different high-pressure processing conditions. Figure 2: Visual observation of pangasius fish gel color under varying salt concentrations and HPP treatments.