## 3 Results and Discussion
### Colour Analysis after Production and Storage  
The highest value of a* colour compound (10.55) after production was confirmed in the SL treatment (_p_ < 0.05), which was due to nitrosyl pigment levels in the product [43,44] (Table 2, Figure 2). Decreasing sodium nitrite to 50 mg/kg and using _S. carnosus_ ATCC 51,365 and _L. fermentum_ S8 bacteria for curing meat enabled obtaining higher redness in the product after cooking than in the control treatment in which NaNO2 at the level of 100 mg/kg was added. No statistically significant (_p_ > 0.05) differences were found between the C (a* = 10.02) and M (a* = 10.09) treatments. It indicates that decreasing the initial amount of sodium nitrite from 100 mg/kg to 50 mg/kg applied in the model composition did not have any effect on the red colour share in the final product. The negative influence of reducing the dose of nitrite used in meat curing on the colour of the final product has been indicated in a great deal of research [1,43,45,46]. However, apart from nitrite added to meat, there are a number of factors (a number of heme being pigments in meat, amount of connective tissue, redox of meat, application of antioxidants and others) that may have an influence on curing process effectiveness, nitrosyl pigments level, and the products colour [1,3,4,41,43,44]. [PERSON] et al. [47] observed that decreasing sodium nitrite from 100 to 50 mg/kg in roasted beef did not have a significant effect on the a* parameter value of the products. Whereas [PERSON] et al. [43] reported that decreasing the nitrite amount from 16 to 13 mg/kg had a significant effect on redness (a*) in cooked poultry rolls. In other research performed on finely ground cooked pork batters it was proved that when using 100 mg/kg of added sodium nitrite a significantly higher a* parameter value in the product was reported compared to a lower sodium nitrite amount (15 mg/kg) [15]. In other studies, sodium nitrite added in the production of Asian sausages (120 mg/kg), has been replaced with cochineal (0.05%), vitamin C (0.05%), vitamin E (0.05%), and celery (1%), which can be a natural source of nitrites and nitrates. The content  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Treatment**} & \multicolumn{4}{c}{**Time of Exposure to Light (Hours)**} \\ \cline{3-7}  & & **0** & **2** & **5** & **24** & **48** \\ \hline L* & C & 64.93 \(\pm\) 0.49 \({}^{\text{\text{\,BA}}}\) & 65.47 \(\pm\) 0.32 \({}^{\text{\,BB}}\) & 65.68 \(\pm\) 0.42 \({}^{\text{\,BB}}\) & 66.06 \(\pm\) 0.43 \({}^{\text{\,BC}}\) & 66.66 \(\pm\) 0.31 \({}^{\text{\,BD}}\) \\  & M & 64.45 \(\pm\) 0.40 \({}^{\text{\,AA}}\) & 65.20 \(\pm\) 0.36 \({}^{\text{\,AB}}\) & 65.31 \(\pm\) 0.25 \({}^{\text{\,AB}}\) & 65.60 \(\pm\) 0.34 \({}^{\text{\,AC}}\)  
of residual nitrites in the control sausage after heat processing was 88.7 mg/kg, while in the sample without the addition of nitrites it was 23.2 mg/kg. The redness (a*) of the sausage where nitrite was added was significantly higher than in the sample without nitrite [46]. After production, all treatments were of a similar b* colour parameter (4.85-4.95). The C treatment significantly (\(p<0.05\)) stood out with the highest L* (64.93) (Table 2). It was proved that SL treatment statistically (\(p<0.05\)) had the highest colour saturation (C* = 11.65). No statistically significant differences (\(p>0.05\)) were found between the C (C* = 11.13) and M (C* = 11.21) treatments (Table 2). At the same time, and significantly, the lowest value of the hue angle was h* = 25.05, proving a general colour tone shift towards the red colour, which was confirmed in the SL treatment. The average values of the h* parameter for the C (25.77) and M (25.79) treatments were not statistically significantly different (\(p>0.05\)). After eight weeks of storage, statistically (\(p<0.05\)) the highest value of the a* colour parameter (10.94) and b* parameter (5.08) were confirmed in the SL. Significantly lower a* and b* parameters values were reported in the C and M treatments (Table 3).