## 3 Results and Discussion
### Assessment of Technological Quality of Stored Meat
Nevertheless, these changes in the meat of chickens stunned with the PLC device differed significantly (\(p<0.05\)) as a function of storage time, which also confirms the significance of changes in the pH parameters (\(p<0.05\)) and tenderness F\({}_{\rm d}\) and D\({}_{\rm P}\) (\(p<0.01\))--Table 3.  
Taking into account that when assessing the quality of packaged meat, the consumer pays mainly attention to the color or its variation in the individual packaging [35], if the color is not acceptable, all other quality characteristics lose their importance; therefore, the influence of an additional factor of storage time (apart from the type of device) on the color changes of fillets and tenderion was determined. The results of measurements of the color of meat stored for 7, 9, 12, and 14 days showed that the values of the L\({}^{*}\) parameter of the color of the external surface (ES) of fillet (PMj) of chickens stunned using the OC device were, respectively: 65.25, 67.99, 68.40, and 62.06, while on the internal surface (IS), they were smaller, respectively, and amounted to: 63.10, 64.98, 66.30, and 61.78. The L\({}^{*}\) values of the tenderion (PMn) during the storage time presented above were lower than the values on the IS surface, which were: 60.48, 61.97, 62.19, and 59.51. The values of the ES color parameters a* and b* of the fillet and tenderion of chickens stunned with OC and stored for 7, 9, 12, and 14 days were, respectively: 2.76, 3.19, 3.24, and 3.96; and 15.53, 14.64, 15.25, and 13.83. The a* and b* values of the IS color of the fillet (except for the a* value of the muscle stored for 7 days) were higher and amountedto, respectively, 2.63, 3.77, 3.67, 4.16 and 17.30, 16.04, 16.99, and 16.29. The a* and b* values of the tenderloin color varied and amounted to: 3.28, 3.45, 5.20, 4.58; and 16.52, 14.43, 16.92, and 15.31. The results of previous own research [28] showed a beneficial effect of the device of own-construction compared to the effect of the Meyn device, expressed in a more even and stable color during storage, regardless of the time and origin of the raw material (Table 4). After 7 and 14 days of storage, the values of the ES color parameter L* of chicken fillets stunned with PLC were higher (by 0.44% and 0.9%), and after 9 and 12 days of storage, they were lower (by 6.2% and 7.8%) than the L* values of chicken fillets stunned with the OC device. After 7 days of storage, the L* values of the IS color of fillets and tenderloins of chickens stunned using the same device (PLC) were higher by 1.3% and 4.5%, while after 9, 12, and 14 days of storage, they were lower by 3.9%, 7.4%, and 0.3%, and at 6.11%, 5.3%, and 0.55% of the L* value of these muscles of chickens stunned with the OC device. In the case of the parameter a*, which is the red color saturation on ES and IS of chicken fillets stunned with the PLC device and stored for 7, 9, 12, and 14 days, its values were higher by approximately 14.5%, 14.1%, 19.1%, and 24% and approx. 45.63%, 11.14%, 15.5%, and 4.56% of the a* value of chicken fillets stunned using the OC device (Table 4). An inverse relationship with changes in the saturation of the red color (a*) was observed with changes in the saturation of the yellow color (b*). The b* values of meat from chickens stunned with the PLC device were lower for: ES of fillets stored for 9 and 12 days by approx. 20 and 15% and IS of fillets stored for 7, 9 and 12 days by approx. 0.2; 9.4 and 5.8% from the b* value of chicken fillets stunned with the OC device. The exceptions were: ES of fillets stored for 7 days--b* values were the same for the OC and PLC devices, and ES and IS of fillets stored for 14 days--b* values were higher by approximately 5.6 and 5.0% for the meat of chickens stunned with the OC device (Table 4).