## 3 Results and Discussion
### Color Changes  
Table 3 presents the effect of different heat treatment (HT) methods on the color parameters (\(L^{*}\), \(a^{*}\), \(b^{*}\)) of the perimeter and center of the cross-section of ST muscle, as well as the total color difference (\(\Delta E\)). The study of the color components on both the sample's perimeter and center allowed us to assess the degree of color uniformity across the product's cross-section during heat treatments at different heating rates. The significantly highest \(L^{*}\) lightness values, both at the perimeter and center of the ST muscle section, were observed in the SV75 and \(\Delta\)T40 samples (62.68/61.15 and 62.22/61.98, respectively, \(p\leq 0.05\)). In contrast, the lowest \(L^{*}\) lightness was recorded in the product treated with the CON method (56.54/53.33, \(p\leq 0.05\)). This effect can be attributed to variations in cooking loss across different methods. [PERSON] et al. [49] have shown that steaks with higher moisture content reflect more light, leading to increased \(L^{*}\) values. Furthermore, the CON-treated product exhibited the lowest redness values both at the perimeter (\(a^{*}=5.35\)) and the center (\(a^{*}=8.24\)) of the cross-section. In contrast, the samples \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multicolumn{1}{c}{**HT**} & \multicolumn{3}{c}{**PC-S**} & \multicolumn{3}{c}{**CC-S**} & \multirow{2}{*}{\(\Delta\)**\(E\)**} \\ \cline{2-2} \cline{6-7} \multicolumn{1}{c}{**Method**} & & \(L^{*}\) & \(a^{*}\) & \(b^{*}\) & \(L^{*}\) & \(a^{*}\) & \(b^{*}\) \\ \hline \multirow{3}{*}{CON} & \(\overline{X}\) & 56.54 a, Y & 5.34 a, X & 8.26 a, X & 53.33 a, X & 8.24 a, Y & 9.16 a, X & 4.48 f \\  & SD & \(\pm\)0.66 & \(\pm\)0.84 & \(\pm\)0.58 & \(\pm\)1.43 & \(\pm\)0.41 & \(\pm\)0.32 & \(\pm\)0.64 \\ \cline{1-1}  & \(\overline{X}\) & 57.12 ab, X & 20.01 f, X & 11.58 d, X & 56.56 b, X & 20.42 e, X & 12.15 c, X & 0.86 a \\ \cline{1-1}  & SD & \(\pm\)1.84 & \(\pm\)0.46 & \(\pm\)0.82 & \(\pm\)2.19 & \(\pm\)0.83 & \(\pm\)0.65 & \(\pm\)0.28 \\ \cline{1-1}  & \(\overline{X}\) & 58.84 ab, X & 15.83 d, X & 10.11 c, X & 57.94 b, X & 16.27 c, X & 10.98 b, X & 1.35 b \\ \cline{1-1}  & SD & \(\pm\)1.01 & \(\pm\)0.59 & \(\pm\)1.02 & \(\pm\)1.67 & \(\pm\)1.21 & \(\pm\)0.38 & \(\pm\)0.49 \\ \cline{1-1}  & \(\overline{X}\) & 62.68 c, X & 8.12 b, X & 9.22 b, X & 61.15 d, X & 9.03 b, Y & 9.88 a, X & 1.97 c \\ \cline{1-1}  & SD & \(\pm\)1.18 & \(\pm\)0.73 & \(\pm\)0.26 & \(\pm\)1.04 & \(\pm\)0.41 & \(\pm\)0.38 & \(\pm\)0.35 \\ \cline{1-1}  & \(\overline{X}\) & 59.75 b, X & 19.12 e, X & 10.28 c, X & 59.29 c, X & 19.57 e, X & 11.12 b, X & 1.49 b \\ \cline{1-1}  & SD & \(\pm\)0.49 & \(\pm\)0.95 & \(\pm\)0.46 & \(\pm\)0.85 & \(\pm\)0.59 & \(\pm\)0.38 & \(\pm\)0.38 \\ \cline{1-1}  & \(\overline{X}\) & 62.22 c, X & 13.14 c, X & 11.24 d, X & 61.98 d, X & 15.52 c, Y & 12.54 c, Y & 2.68 e \\ \cline{1-1}  & SD & \(\pm\)1.08 & \(\pm\)0.49 & \(\pm\)0.75 & \(\pm\)1.47 & \(\pm\)1.06 & \(\pm\)0.43 & \(\pm\)0.47 \\ \cline{1-1}  & \(\overline{X}\) & 60.83 b, X & 16.21 d, X & 12.02 e, X & 60.75 cd, X & 18.32 d, Y & 12.81 c, X & 2.29 d \\ \cline{1-1}  & SD & \(\pm\)1.15 & \(\pm\)0.94 & \(\pm\)0.44 & \(\pm\)1.22 & \(\pm\)0.29 & \(\pm\)0.47 & \(\pm\)0.52 \\ \hline \end{tabular}  
* PC–S—perimeter of cross-section; CC–S—center of cross-section.
* (a, b...) show the significant differences in a column (\(p\leq 0.05\)); (X, Y...) show the significant differences in a row (\(p\leq 0.05\)).  
\end{table} 
Table 3: The changes in color coordinates \(L^{*}\), \(a^{*}\), and \(b^{*}\) on the PC-S and CC-S surfaces and the \(\Delta E\) values on the cross-section of the product obtained from ST muscle depending on the HT method. processed using SV55 and \(\Delta\)T20 showed the highest redness, with values of 20.01 and 19.12 at the perimeter and 20.42 and 19.57 at the center, respectively (\(p\leq\) 0.05). The increased redness in SV and \(\Delta\)T samples resulted from lower center temperatures, which minimized myoglobin denaturation, preserving the red color in the cooked ST muscle.