## 3 Results and Discussion
### Residual Nitrite Content and Percent Cured Meat Pigment  
The amount of residual nitrite in cured meat products depends on several factors, including the amount of nitrite added in the curing process, the type of meat used, curing time and temperature, and the presence of other ingredients that may influence the direction of the nitrite reaction in the final product ([PERSON] _et al._, 2018). Table 3 shows residual nitrite levels in liver pates cured with nitrites from various sources and stored for 7 days. The NC group had the lowest nitrite concentration during the storage period (\(p<0.05\)). This was probably due to inadvertent contamination of the product with nitrites, e.g., from the nitrogen metabolism of the animal and feed ([PERSON] _et al._, 2018). The calculated amount of added nitrite ions for groups PC1 and PTEW1 was 40 ppm, while for groups PC2 and PTEW2 it was 80 ppm. As expected, liver pates from groups PC1 and PTEW1 showed significantly lower (\(p<0.05\)) nitrite content from day 1 than pates from groups PC2 and PTEW2. This was due to the lower amount of nitrite ions added to the batters during production. Importantly, in terms of residual nitrite throughout the entire storage period, groups with plasma-activated egg whites did not differ from groups that contained the same amount of nitrite ions derived from sodium nitrite (\(p\geq 0.05\)). Although [PERSON] et al. (2018) showed that the residual nitrite content in emulsion-type sausages containing plasma-treated water decreases more rapidly during storage, our study found no significant differences between the residual nitrite content of the PC1 and PTEW1 groups and that of the PC2 and PTEW2 groups on individual days of storage. The obtained results might provide support for the effectiveness of using plasma-treated egg whites as a potential replacement for traditional nitrite-based additives in meat preservation. [PERSON] et al. (2018) reported that although the nitrite content of the liver pates decreased the most after the first 24 h compared to the initial level due to heat treatment, it continued to decline gradually during storage. Similarly in our research, in all cured samples (PC1, PTEW1, PC2, PTEW2) a significant decrease in nitrite content (\(p<0.05\)) was observed with the extension of storage time, which was consistent with the literature data for pates containing nitrites ([PERSON] _et al._, 2018), and may be related to the reactivity of nitrites with meat ingredients, as well as oxidation to nitrates ([PERSON] _et al._, 2018). During the curing process of meat, nitrite reacts with myoglobin to form nitrosylmyoglobin. As a result of heat treatment, unstable nitrosylmyoglobin reacts further with nitric oxide to form nitrosyl hemochrome, which is responsible for the characteristic pink color of cured meat products ([PERSON] _et al._, 2018). As expected, throughout 7 days of storage, liver pates from the NC group were characterized by significantly lower nitrosyl hemochrome content (\(p<0.05\) \begin{table}
\begin{tabular}{l l c c c c} \hline \hline
**Parameters** & **Group 2** & **1 Day** & **3 Day** & **5 Day** & **7 Day** \\ \hline \multirow{6}{*}{pH [–]} & NC & 6.33 \(\pm\) 0.02 & 6.36 \(\pm\) 0.01 & 6.39 \(\pm\) 0.01 & 6.42 \(\pm\) 0.02 \\  & PC1 & 6.32 \(\pm\) 0.04 & 6.34 \(\pm\) 0.02 & 6.39 \(\pm\) 0.01 & 6.42 \(\pm\) 0.01 \\ \cline{1-1}  & PC2 & 6.33 \(\pm\) 0.03 & 6.36 \(\pm\) 0.01 & 6.41 \(\pm\) 0.01 & 6.41 \(\pm\) 0.01 \\ \cline{1-1}  & PTEW1 & 6.35 \(\pm\) 0.04 & 6.34 \(\pm\) 0.03 & 6.40 \(\pm\) 0.01 & 6.40 \(\pm\) 0.02 \\ \cline{1-1}  & PTEW2 & 6.33 \(\pm\) 0.04 & 6.33 \(\pm\) 0.02 & 6.41 \(\pm\) 0.01 & 6.40 \(\pm\) 0.02 \\ \hline \hline \end{tabular}  
* SE–standard error; 2 NC—negative control (liver páts without a nitrite source); PC1—positive control (liver páts with 60 ppm of sodium nitrite); PTEW1—liver páts with plasma-treated egg white containing 40 ppm NO2 –; PC2—positive control (liver páts with 120 ppm of sodium nitrite); PTEW2—liver páts with plasma-treated egg white containing 80 ppm NO2 –.  
\end{table}