## 3 Results
### Chemical Composition and Physicochemical Properties of Fermented Loins  
The moisture, protein, collagen and fat content of the fermented loins is shown in Table 3. As expected, the proximate chemical composition of samples were not affected by the level of nitrate. Meat products were characterized by a high protein content ranging from 26.72 to 28.91%. The salt concentration in four formulations of fermented loins was similar due to the same amount added during production and a similar degree of drying of the products during processing. The moisture content was in the range of 65.15 to 66.43%. Table 4 shows the pH and water activity values of fermented loins with varying levels of nitrate. Statistical analysis showed that the process factors such as treatments and storage time influenced (\(p\leq 0.05\)) the pH and water activity. At the beginning of the storage (month zero), lower pH values were detected for the samples containing nitrate at the level 100 and 150 mg kg\({}^{-1}\) compared to the samples FL0 and FL50. No statistically significant changes in pH were observed for the FL0 and FL50 samples with a storage time. Samples of fermented loin with higher levels of added nitrate (FL100, FL150) in four months of storage were characterized by a significantly higher pH compared to the previous storage periods. Water activity did not differ statistically significantly between the formulations. The a\({}_{\rm w}\) values ranged from 0.917 to 0.940 during the six-month storage period. With increased storage time, a decrease in water activity was observed for all samples. The lowest values were found in the sixth month of storage (0.917-0.922). \begin{table}
\begin{tabular}{c c c} \hline  & & **Raw Material (Meat)** \\ \hline \multirow{4}{*}{Proximate chemical composition [\%]} & Fat & 3.92 \(\pm\) 0.83 \\ \cline{2-3}  & Protein & 21.30 \(\pm\) 0.99 \\ \cline{2-3}  & Moisture & 73.45 \(\pm\) 1.81 \\ \cline{2-3}  & Collagen & 1.08 \(\pm\) 0.64 \\ \hline \multirow{4}{*}{Basic technological parameters} & pH & 5.28 \(\pm\) 0.02 \\ \cline{2-3}  & a\({}_{\rm w}\) & 0.989 \(\pm\) 0.003 \\ \cline{2-3}  & L* & 63.71 \(\pm\) 4.64 \\ \cline{2-3}  & a* & 6.21 \(\pm\) 1.29 \\ \cline{2-3}  & b* & 15.60 \(\pm\) 1.30 \\ \hline Total pigment content [mg kg\({}^{-1}\)] & 72.31 \(\pm\) 4.27 \\ \hline Heme iron content [mg kg\({}^{-1}\)] & 6.30 \(\pm\) 0.40 \\ \hline TBARS [mg kg\({}^{-1}\)] & 0.41 \(\pm\) 0.03 \\ \hline \end{tabular} a\({}_{\rm w}\)—water activity, L*—lightness, a*—redness, b*—yellowness.  
\end{table} 
Table 2: Proximate chemical composition and basic technological parameters characterizing the raw materials (mean \(\pm\) standard deviation). \begin{table}
\begin{tabular}{c c c c c} \hline
**Component [\%]** & **FL0** & **FL50** & **FL100** & **FL150** \\ \hline \multirow{2}{*}{Fat Protein Moisture} & 4.21 \(\pm\) 0.24 & 4.39 \(\pm\) 0.48 & 3.86 \(\pm\) 0.42 & 4.80 \(\pm\) 0.53 \\ \cline{2-5}  & 27.82 \(\pm\) 0.71 & 28.57 \(\pm\) 0.73 & 28.91 \(\pm\) 0.73 & 26.72 \(\pm\) 0.68 \\ \cline{2-5}  & 66.29 \(\pm\) 3.41 & 65.15 \(\pm\) 3.26 & 65.51 \(\pm\) 3.28 & 66.43 \(\pm\) 3.32 \\ \cline{2-5}  & 0.78 \(\pm\) 0.19 & 0.72 \(\pm\) 0.15 & 0.76 \(\pm\) 0.13 & 1.05 \(\pm\) 0.21 \\ \cline{2-5}   Salt & 1.73 \(\pm\) 0.13 & 1.73 \(\pm\) 0.11 & 1.81 \(\pm\) 0.11 & 1.73 \(\pm\) 0.08 \\ \hline \end{tabular}
\end{table} 
Table 3: Proximate chemical composition of fermented loins (mean \(\pm\) standard deviation). Regarding lipid oxidation, TBARS values were significantly higher in fermented losing without nitrate (FL0) and the lowest level of nitrate addition (FL50) compared to samples FL100 and FL150 at the end of processing (month zero) and after one month of storage (Table 5). An increase in TBARS in the case of all formulations was observed in four months of storage. Then, it significantly decreased after six months of storage to the lowest value in the entire storage period (1.47 to 1.64 mg kg\({}^{-1}\)).