## 3 Results and Discussion  
### Colour Parameters and pH  
The pH value may significantly determine the technological properties of meat. Therefore, the initial pH value of goose breast meat was tested. The samples did not differ significantly in the initial value of this characteristic, and the pH value of meat was in the range of 5.76-5.82. The indicated values are consistent with the results presented by [PERSON] et al. [4]. Table 1 summarises the results of the instrumental measurement of the colour parameters lightness (L*), redness (a*) and yellowness (b*), as well as calculated values determining the hue angle (h) and chroma (C) of goose breast meat processed in various experimental conditions. Instrumental colour parameters were differentiated by the heat treatment method, with significant differences identified between products heated using the SV method and those heated using the OV method. The lightness (L*) of samples heated using the SV method, regardless of the heating time, was significantly higher than that of samples heated using the OV method. A similar relationship was found for b* values. However, in meat heated using the OV method, significantly higher values of a* were found compared to samples heated using the SV method, regardless of the heating temperature used. Pectoral muscles heated using the SV method were also characterised by higher values of the hue angle (h). It was also found that the value of the h parameter of meat heated at OV90 was significantly lower compared to those heated at a lower temperature (OV80). The heating time of goose breasts using the SV method did not significantly differentiate the chroma value (C) of the products, although it was significantly higher compared to the OV samples. Based on the \(\Delta\)E and NBS unit values, the changes in the analysed colour parameters were classified as considerable in the case of OV samples (NBS OV80 = 9.21 and NBS OV90 = 6.58) and as significant in SV samples (NBS SV4 = 16.47 and NBS SV10 = 19.49). The CIE Lab colour parameters determined for raw goose breast meat in this study were similar to the values indicated by [PERSON] et al. [37] and [PERSON] et al. [30]. In the indicated studies, the value of the L* in the breast muscle of the White Kolda goose ranged from 37.87 to 40.25. At the same time, the values of parameters a* and b* were in the ranges of 19.30-20.02 and 1.33-3.23, respectively. The colour of fresh meat depends mainly on the content of heme pigments and the share of individual myoglobin fractions: oxymyoglobin (MbO\({}_{2}\)), myoglobin (Mb) and metmyoglobin (MetMb). The share of individual myoglobin fractions in goose meat may vary depending on the bird variety [4]. \begin{table} \begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Parameters**} & \multirow{2}{*}{**Raw Meat**} & \multicolumn{4}{c}{**Heat Treatment**} \\ \cline{3-6}  & & **SV4** & **SV10** & **OV80** & **OV90** \\ \hline L* & 34.54 b  \(\pm\) 2.36 & 47.72 a  \(\pm\) 2.79 & 51.17 a  \(\pm\) 2.18 & 38.54 b  \(\pm\) 0.71 & 34.51 b  \(\pm\) 0.67 \\ \hline a* & 15.89 c  \(\pm\) 1.59 & 6.54 b  \(\pm\) 0.11 & 6.48 b  \(\pm\) 0.87 & 7.90 a  \(\pm\) 0.69 & 9.58 a  \(\pm\) 0.88 \\ \hline b* & 3.45 c  \(\pm\) 1.87 & 10.80 a  \(\pm\) 0.26 & 12.05 a  \(\pm\) 0.39 & 7.76 b  \(\pm\) 0.75 & 6.61 b  \(\pm\) 0.78 \\ \hline h & 13.08 d  \(\pm\) 3.78 & 58.83 a  \(\pm\) 3.89 & 61.74 a  \(\pm\) 1.46 & 44.50 b  \(\pm\) 3.27 & 34.61 c  \(\pm\) 0.79 \\ \hline C & 19.34 a  \(\pm\) 3.04 & 17.35 a  \(\pm\) 0.68 & 18.53 a  \(\pm\) 0.62 & 15.66 b  \(\pm\) 0.84 & 16.19 b  \(\pm\) 0.52 \\ \hline \(\Delta\)E & - & 17.90 b  \(\pm\) 0.38 & 21.19 a  \(\pm\) 1.77 & 10.01 c  \(\pm\) 0.32 & 7.16 d  \(\pm\) 0.88 \\ \hline NBS & - & 16.47 b  \(\pm\) 0.38 & 19.49 a  \(\pm\) 1.77 & 9.21 c  \(\pm\) 0.32 & 6.58 d  \(\pm\) 0.88 \\ \hline \hline \end{tabular}   
* Values in rows with different upper case letters differ at \(p<0.05\). SV4—The changes in meat lightness resulting from heat treatment presented in this study were consistent with [PERSON]'s results [38].