## 3 Results and Discussion
### Assessment of the Quality of Fresh Fillets
The results of measurement of the parameters (L*, a*, b*) of the color of fresh fillets showed that the L* values of the color of the external (ES) and internal (IS) surfaces of the m. _pectoralis major_ (PMj) and m. _pectoralis minor_ (PMn) muscles from chickens stunned using the OC device were, respectively, approx. 67, 63, and 58, and were higher than the L* values of the corresponding muscles of chickens stunned with the PLC device by approx. 2.5%, 2%, and 2%. The a* ES and IS values of the above-mentioned muscles of chickens stunned with the OC device were 2.94, 3.19, and 4.22, respectively, and were smaller than the a* of the corresponding muscles of chickens stunned with the PLC device by approx. 9%, 5%, and 8%. The b* values of ES and IS--PMj colors of chickens stunned with the OC device were 12.41 and 15.81, respectively, and were higher than the b* values of this muscle of chickens stunned with the PLC device by approximately 8.4% and 4.6%. The b* value of the PMn color of chickens stunned using the OC and PLC devices was the same--15.12 (Table 2). The results of color parameter measurements clearly indicate that the use of the OC device results in greater meat brightness (L* \(\approx\) 67-58), and low values of the a* parameter--red color saturation (2.94-4.22) and high values of the b* parameter--yellow color saturation (12.41-15.12), which are probably the result of a smaller number of hemorrhages occurring on the inner and outer surfaces (Figure 3A) and defects (Figure 3B). Statistical analysis of chicken meat color parameters showed significant differences (\(p\) < 0.01; \(p\) < 0.05) between the L* of ES color of fillet and tenderloin of chickens stunned using the OC and PLC devices. Significant differences (\(p\) < 0.01) were also observed between the b* color parameter of chicken fillets stunned with OC and PLC devices (Table 2). \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Measured Parameter**} & \multicolumn{2}{c}{**Type of Device**} \\ \cline{2-3}  & **OC** & **PLC** \\ \hline pH\({}_{9h}\) & 5.88 \(\pm\) 0.11 & 5.90 \(\pm\) 0.07 \\ F\({}_{\text{P}}\) [N] & 25.44 \(\pm\) 4.31 A & 27.82 \(\pm\) 2.35 B \\ D\({}_{\text{P}}\) [mm] & 7.88 \(\pm\) 0.76 A & 9.32 \(\pm\) 1.73 B \\ Cooking loss [\%] & 14.75 \(\pm\) 1.62 & 15.06 \(\pm\) 0.55 \\ \hline \hline \end{tabular} \({}^{\Lambda\text{-B}}\)—significant differences between rows (devices), \(p\) < 0.05.  
\end{table} 
Table 1: The values (mean \(\pm\) standard deviation) of pH\({}_{9h}\), maximum puncture force (F\({}_{\text{P}}\)), deformation (D\({}_{\text{P}}\)), and cooking loss from meat of chickens stunned using the own-construction (OC) and Polish company (PLC) devices. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Type of Device**} & \multicolumn{2}{c}{**m.pectoralis major (PMj)**} & \multicolumn{3}{c}{**Analysis of Variance,**} \\  & **External** & **Internal** & **minor (PMn)** & \multicolumn{3}{c}{**Variable Surface**} \\ \cline{3-6}  & **Surface (ES)** & **Surface (IS)** & **ES-IS** & **IS-PMn** & **PMn-ES** \\ \hline \hline \multicolumn{6}{c}{L*} \\ \hline OC & 66.92 \(\pm\) 2.39 b [FOOTNOTE:b]Footnote b—significant differences between rows, \(p\) < 0.01; \(\text{A}^{\text{-B}}\)—significant differences between rows, \(p\) < 0.01; \(\text{S}^{\text{--}}\)—significant differences between rows, \(p\) < 0.05; **——significant differences between surfaces, \(p\)  
The conducted research shows that, regardless of the stunning device used, the L* values of the color of the fillet on the external surface were higher and differed significantly from the L* value of the color on the internal surface of the fillet and tenderloin. The obtained results confirm the results of research by [PERSON] and [PERSON] [23] and [PERSON] et al. [24], where the outer surface of the fillet was lighter than the internal surface. Therefore, measuring the color on the external surface may pose a problem when classifying the raw material into a specific quality group [25].