## 3 Results and Discussion
### Physicochemical Analysis
The initial cutting force for the reference (CNT) samples was 5.16 \(\pm\) 0.17 N, while for the HPP samples, it was 4.92 \(\pm\) 0.26 N. These values did not change during storage under either isothermal or dynamic storage conditions for all samples, exhibiting slightly, though insignificantly, decreased final means (\(p>0.05\)) of 4.95 \(\pm\) 0.28 N and 4.87 \(\pm\) 0.72 N for the CNT and the HPP samples, respectively. The initial values of the textural attributes obtained after the double compression test on the slice of CNT frankfurter-type sausages were calculated as 4.65 \(\pm\) 0.26 N, 0.74 \(\pm\) 0.01, 0.069 \(\pm\) 0.007 N-s, 3.44 \(\pm\) 0.19 N-s, and 3.54 \(\pm\) 0.11 N-s for hardness, cohesiveness, adhesiveness, gumminess, and chewiness, respectively, whereas the index of elasticity was found  
Figure 2: Changes in color parameters of (**a**) CNT and (**b**) HPP frankfurter-type sausages during storage under different temperature conditions. The bars represent the mean values, while the error bars represent the standard deviation values out of three replicates. The symbol *** is used to indicate significant differences (\(p<0.05\)) among same parameters based on [PERSON]’s post hoc comparison test. equal to 1.00 \(\pm\) 0.02 for all studied cases. At the end of the storage period, a slight, yet significant (_p_ < 0.05), change in the main textural attributes was detected, exhibiting mean values of 5.05 \(\pm\) 0.24 N, 0.84 \(\pm\) 0.06, 0.029 \(\pm\) 0.002 N-s, 4.25 \(\pm\) 0.41 N-s, and 4.37 \(\pm\) 0.14 N-s for hardness, cohesiveness, adhesiveness, gumminess, and chewiness, respectively, without presenting significant variations among samples stored at different temperature conditions. Similarly, the corresponding values for the main textural attributes of HPP frankfurter-type sausages were calculated as 4.60 \(\pm\) 0.17 N, 0.83 \(\pm\) 0.04, 0.064 \(\pm\) 0.004 N-s, 3.83 \(\pm\) 0.35 N-s, and 3.94 \(\pm\) 0.36 N-s for hardness, cohesiveness, adhesiveness, gumminess, and chewiness, respectively. Based on the results of the texture profile analysis, it is evident that the application of HPP affected only the cohesiveness of the frankfurter-type sausages, leading to a significant (_p_ < 0.05) increase of approximately 0.1 units, indicating that more coherent products are formed after HPP treatment. Similar results have been previously reported, where the application of pressures up to 600 MPa at 25 \({}^{\circ}\)C for 5 min also led to a comparable increase in the cohesiveness values of bratwurst sausages [9,41]. At the end of the storage period, no significant (_p_ > 0.05) changes in the main textural attributes' values of HPP sausages were observed, regardless of the storage temperature. The water activity (a\({}_{\mathrm{w}}\)) of the frankfurter sausages with storage time was also monitored in the present study. The results of the a\({}_{\mathrm{w}}\) measurement of the frankfurter-type sausage samples in relation to storage time, under isothermal conditions of 4, 8, 12, and 18 \({}^{\circ}\)C, are presented in Figures 3a-d and 4a-d for the CNT and HPP samples, respectively. The sausages had a\({}_{\mathrm{w}}\) values ranging from 0.978 to 0.994 (Figures 3 and 4). Based on the results of the measurement of a\({}_{\mathrm{w}}\), the greatest fluctuations were noted for the samples exhibiting greater and more evident spoilage, with liquid exudation in the packaging, mainly for the reference samples. Regarding the HPP samples, the smallest and statistically insignificant differences (_p_ > 0.05) were observed throughout the storage period and for all the studied temperature conditions (constant and dynamic). As for the samples stored  
Figure 3: Changes in water activity (a\({}_{\mathrm{w}}\)) in CNT frankfurter-type sausages during storage at **(a)** 4, **(b)** 8, **(c)** 12, and **(d)** 18 \({}^{\circ}\)C. The bars represent the mean values, while the error bars represent the standard deviation out of three replicates.