## 3 Results and Discussion
### Physicochemical Analysis
Different lowercase letters within each figure indicate significant differences (_p_ < 0.05) among samples based on [PERSON]’s post hoc comparison test. under dynamic storage conditions, it was observed that the samples stored under conditions with T\({}_{\text{eff}}\) = 4.5 \({}^{\circ}\)C exhibited similar behavior to those stored under isothermal conditions at 4 \({}^{\circ}\)C, and the samples stored under conditions with T\({}_{\text{eff}}\) = 11.1 \({}^{\circ}\)C exhibited similar behavior to those stored under isothermal conditions at 12 \({}^{\circ}\)C (Figure 5). Apart from microbial spoilage, lipid oxidation is one of the main factors affecting the quality of meats and poultry. From a sensory perspective, lipid oxidation leads to rancidity, which is undesirable to consumers [42]. Additionally, lipid oxidation has been associated with an increase in protein oxidation [43], a negative impact on texture [44],  
Figure 4: Changes in water activity (a\({}_{\text{w}}\)) in HPP 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. Different lowercase letters within each figure indicate significant differences (\(p<0.05\)) among samples based on [PERSON]’s post hoc comparison test. Figure 5: Comparison of the changes in water activity (a\({}_{\text{w}}\)) values in HPP-treated samples during storage under dynamic conditions with T\({}_{\text{eff}}\) equal to **(a)** 4.5 \({}^{\circ}\)C and **(b)** 11.1 \({}^{\circ}\)C to the corresponding ones under isothermal storage conditions. The bars represent the mean values, while the error bars represent the standard deviation out of three replicates. Different lowercase letters within each figure indicate significant differences (\(p<0.05\)) among samples based on [PERSON]’s post hoc comparison test. and discoloration of meat products [45]. For this reason, it was considered necessary to determine the degree of oxidation. The results of the lipid oxidation show that the MDA values ranged from 0.82 \(\pm\) 0.11 to 1.52 \(\pm\) 0.03 mg MDA/kg of frankfurter-type sausage. Independent of the formulation used to manufacture frankfurters, throughout storage, the TBARS values remained below the maximum acceptable limit, which is reported as the limit beyond which processed meat products will normally develop objectionable odors/tastes. For processed meats (like sausages, bacon), the limits may be a bit higher, around 2-4 mg MDA/kg, due to added ingredients and processing steps that can influence lipid oxidation [46; 47]. Similar results were reported by [PERSON] et al. [48] and [PERSON] et al. [49], where the TBARS values of dry-cured Iberian ham and frankfurters, respectively, increased during chilled storage. Therefore, lipid oxidation did not serve as a significant indicator for the spoilage of these products. The results of the present study are not in agreement with other researchers who have shown that HPP can accelerate lipid oxidation on HPP meat products [50] by triggering intrinsic pro-oxidants such as myoglobin [51].