## 3 Results and Discussion
### Oxidation-Reduction Potential, pH, and TBARS Index
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & **Treatment** & \multicolumn{3}{c}{**Storage Time (Days)**} & **Treatment** & **Time** & **Treatment** \(\times\) **Time** \\ \cline{2-7}  & & **0** & **7** & **14** & \(p\) & \(p\) & \(p\) \\ \hline pH & C & 5.83 \(\pm\) 0.09\({}^{\text{cA}}\) & 5.82 \(\pm\) 0.02\({}^{\text{cA}}\) & 5.85 \(\pm\) 0.09 \({}^{\text{bA}}\) & *** & **+** & * \\  & V1 & 5.69 \(\pm\) 0.04 \({}^{\text{bA}}\) & 5.69 \(\pm\) 0.02 \({}^{\text{bA}}\) & 5.75 \(\pm\) 0.17 \({}^{\text{aB}}\) & & & \\  & V3 & 5.50 \(\pm\) 0.03 \({}^{\text{aA}}\) & 5.73 \(\pm\) 0.07 \({}^{\text{bB}}\) & 5.69 \(\pm\) 0.05 \({}^{\text{aB}}\) & & & \\  & V5 & 5.46 \(\pm\) 0.04 \({}^{\text{aA}}\) & 5.57 \(\pm\) 0.02 \({}^{\text{aB}}\) & 5.63 \(\pm\) 0.01 \({}^{\text{cC}}\) & & & \\ \hline  & C & 37.07 \(\pm\) 5.67\({}^{\text{aB}}\) & 376.05 \(\pm\) 2.91 \({}^{\text{aB}}\) & 358.50 \(\pm\) 5.16\({}^{\text{aA}}\) & *** & **+** & *** \\  & V1 & 371.50 \(\pm\) 4.63 \({}^{\text{aA}}\) & 382.43 \(\pm\) 4.29 \({}^{\text{bB}}\) & 379.55 \(\pm\) 7.42 \({}^{\text{bB}}\) & & & \\  & V3 & 392.58 \(\pm\) 1.06 \({}^{\text{bB}}\) & 382.23 \(\pm\) 2.08 \({}^{\text{bA}}\) & 384.43 \(\pm\) 6.35 \({}^{\text{bA}}\) & & & \\  & V5 & 390.10 \(\pm\) 4.06 \({}^{\text{bA}}\) & 396.15 \(\pm\) 1.14 \({}^{\text{cB}}\) & 389.55 \(\pm\) 3.59 \({}^{\text{cA}}\) & & & \\ \hline TBARS & C & 0.58 \(\pm\) 0.09 \({}^{\text{aA}}\) & 0.54 \(\pm\) 0.06 \({}^{\text{aA}}\) & 0.89 \(\pm\) 0.08 \({}^{\text{aB}}\) & * & *** & **+** \\ (mg/kg) & V1 & 0.61 \(\pm\) 0.04 \({}^{\text{aA}}\) & 0.71 \(\pm\) 0.04 \({}^{\text{aB}}\) & 0.86 \(\pm\) 0.04 \({}^{\text{cA}}\) & & & \\  & V3 & 0.67 \(\pm\) 0.05 \({}^{\text{bA}}\) & 0.64 \(\pm\) 0.01 \({}^{\text{bA}}\) & 0.86 \(\pm\) 0.03 \({}^{\text{aB}}\) & & & \\  & V5 & 0.55 \(\pm\) 0.04 \({}^{\text{aA}}\) & 0.69 \(\pm\) 0.03 \({}^{\text{bB}}\) & 0.91 \(\pm\) 0.05 \({}^{\text{aC}}\) & & & \\ \hline \hline \end{tabular}  
* \({}^{\text{aC}}\) Means in the same columns with different superscript small letters differ significantly (_p_ \(<\) 0.05); \({}^{\text{A-C}}\) Means in the same row with different superscript capital letters differ significantly (_p_ \(<\) 0.05); C—control sausage without apple vinegar; V1, V3, V5—sausage with apple vinegar 1, 3, and 5%, respectively. _p_: significance of effects; treatment; time; treatment-time interaction; \({}^{\text{aC}}\)_p_ \(<\) 0.05; \({}^{\text{aB}}\)_p_ \(<\) 0.01; \({}^{\text{aB}}\)_p_ \(<\) 0.001.  
\end{table} 
Table 4: The values of oxidation-reduction potential, pH, and TBARS index of sausage (means \(\pm\) standard deviation error). process with vinegar. The acidity level of meat affects its ability to hold water. Generally, meat can retain more water when its pH level is either above or below the isoelectric point of the meat proteins. It is worth noting that processed meat products with a lower pH level are less likely to develop pathogenic microbial growth, which ultimately improves their safety and extends their shelf life [43]. The pH of all samples increased throughout the refrigerated storage period, similar to [PERSON] et al. 's findings [44]. The elevation in the pH level of meat and its derived products is linked to the liberation of basic compounds, which include the imidazole, sulfhydryl, and hydroxyl groups, during processing and storage. We observed the treated batches (V3, V5) as the storage period progressed. The study revealed a noteworthy impact of treatment and storage time on the oxidation-reduction potential value with a \(p\)-value of less than 0.001. Furthermore, an interaction between the treatment and storage time was observed for the oxidation-reduction potential, as indicated in Table 4. The sausage treated with apple vinegar at the 3% and 5% levels showed a significantly higher level of oxidation-reduction potential (ORP) with a range of 13-16 mV compared to the control treatments, immediately after the production process. The lowest ORP value was recorded in the V1 and C treatment at 371.50 mV and 377.08 mV, respectively.