## 4 Discussion  
The current study assessed the impact of the level of nitrate addition on the quality of traditionally produced fermented loans. It has been shown that changes in the basic meat components during production changed the chemical composition of the products as compared to the properties of the raw material. The values of the physicochemical properties of raw material used for fermented loin production were typical for good-quality fresh pork and similar to those obtained by Keska and Stadnik [31]. Water loss during drying, by almost 10% compared to the moisture content in raw material, resulted in a higher concentration of nutrients, especially proteins. The fermented loins had a relatively high average protein content in the range of 26.72 to 28.91%. The significant loss of water during production implied also that the loins had a high total pigment content, over 20 mg kg\({}^{-1}\) more compared to the raw material at the end of production. The reduction of the water content and the biochemical changes taking place during fermentation and drying resulted in the reduction of the water activity to the value 0.917 to 0.940 depending of the storage time. The observed value of water activity indicated unfavorable conditions preventing the growth of the most popular bacteria in meat products such as _Listeria monocytogenes_ and _Clostridium botulinum_[32]. With increased storage time, a decrease in water activity was observed for all fermented ions which may point to the production of low molecular weight nitrogen compounds from the decomposition of meat protein during storage by meat and microbial enzymes [33]. The average water activity in fermented loins with different levels of nitrate was similar to that found by [PERSON] et al. [34] for dry-cured loins. Unfortunately, no decrease in pH was achieved during the production in relation to the raw material, which indicates insufficient lactic acid bacteria growth during production. The increase of pH value during processing may result from many factors including proteolytic changes. According to [PERSON] et al. [35], as a result of proteolysis, which causes, among others, protein breakdown, decarboxylation and deamination, substances such as ammonia and amines can be released. In this context, the progressive increase in the content of these compounds reduces the acidity of fermented meat products. A very important aspect of the quality of fermented meat products is the oxidative stability of the lipids they contain. At the beginning of the storage period, the TBARS values were significantly higher in fermented loins without nitrate and with the lowest \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Parameter** & **FL0** & **FL50** & **FL100** & **FL150** \\ \hline N-Nitrosodibutylamin (NDBA) [ug kg\({}^{-1}\)] & \textless{}5 & \textless{}5 & \textless{}5 & \textless{}5 \\ \hline N-Nitrosodiethylamine (NDEA) [ug kg\({}^{-1}\)] & \textless{}5 & \textless{}5 & \textless{}5 & \textless{}5 \\ \hline N-Nitrosodimethylamine (NDMA) [ug kg\({}^{-1}\)] & \textless{}5 & \textless{}5 & \textless{}5 & \textless{}5 \\ \hline N-Nitrosodipropylamin (NDPA) [ug kg\({}^{-1}\)] & \textless{}5 & \textless{}5 & \textless{}5 & \textless{}5 \\ \hline N-Nitrosomorpholin (NMOR) [ug kg\({}^{-1}\)] & \textless{}5 & \textless{}5 & \textless{}5 & \textless{}5 \\ \hline N-Nitrosopiperidin (NPIP) [ug kg\({}^{-1}\)] & \textless{}5 & \textless{}5 & \textless{}5 & \textless{}5 \\ \hline N-Nitrosopyrrolidin [ug kg\({}^{-1}\)] & \textless{}5 & \textless{}5 & \textless{}5 & \textless{}5 \\ \hline NaNO\({}_{2}\) [mg kg\({}^{-1}\)] & \textless{}10 & \textless{}10 & \textless{}10 & \textless{}10 \\ \hline NaNO\({}_{3}\) [mg kg\({}^{-1}\)] & \textless{}10 & 11.0 \(\pm\) 2.0 & 17.0 \(\pm\) 2.0 & 19.0 \(\pm\) 1.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Nitrosamine, nitrite and nitrate residues in fermented loins after production. level of nitrate addition compared to samples with the nitrate addition in the amount of 100 and 150 mg kg\({}^{-1}\).