## 3 Results and Discussion
### Combined-Treated Samples
\begin{table}
\begin{tabular}{l l r r r} \hline  & & \(p\) **(Order of** & \(p\) **(Pressure Level)** & \(p\) **(Order of Treatments** \\  & & **Treatments)** & \(p\) **(Pressure Level)** & \(\times\) **Pressure Level)** \\ \hline Moisture & (\%) & 0.085 & 0.101 & 0.361 \\ Weight loss & (\%) & \textless{}0.001 *** & \textless{}0.001 *** & \textless{}0.001 \\ pH & & 0.197 & 0.859 & 0.557 \\ Color & L* & 0.105 & 0.154 & 0.245 \\ a* & \textless{}0.001 *** & \textless{}0.001 *** & 0.565 \\ b* & 0.030 * & \textless{}0.001 *** & 0.619 \\ DSC & denaturation heat (J/g) & 0.067 * & 0.003 ** & 0.020 * \\ Texture & hardness (N) & 0.508 & \textless{}0.001 *** & 0.817 \\ TBARS & mg MDA/kg & 0.989 & 0.043 * & 0.985 \\ Microbiology & anaerobic TVC (log\({}_{10}\), CFU/g) & 0.373 & 0.898 & 0.407 \\  & aerob TVC (log\({}_{10}\), CFU/g) & 0.268 & 0.523 & 0.957 \\  & _L. monocytogenes_ TVC (log\({}_{10}\) & n/a & n/a & n/a \\  & CFU/g) & & & \\ \hline \end{tabular}  
* significant effect at \(p<0.001\); *
* significant effect at \(p<0.01\);
* significant effect at \(p<0.05\). n/a—not applicable; below detection limit in all cases.  
\end{table} 
Table 5: The effects of the treatment order, the pressure level, and their interaction, based on the measurements of the combined heat- and pressure-treated samples. Increasing pressure levels resulting in higher lipid oxidation of beef and chicken breast muscle, and marine and pork fats were reported by [PERSON] and [PERSON] [43] and [PERSON] et al. [23]. Despite the very clear effect of the pressure level on the TBARS values, this factor only led to significant differences (\(p<0.043\)) due to higher variance within groups. Regarding the pressure level, our results are similar to those found by [PERSON] et al. [22] in a detailed study of pork lipid oxidation. As the pressure level of the treatments increased, more secondary oxidation products and higher TBARS values were detected in their research (the peak TBARS value was measured at 400 MPa and after heat treatment at a lower temperature). The effect of storage was not examined in that case. Our measurements of TBARS values showed no change within the 21-day storage period at 2 \({}^{\circ}\)C and a minimal rise at 8 \({}^{\circ}\)C. The treatment order had no effect on this parameter. The result of the thermal analysis shows a significant impact (\(p<0.001\)) of the pressure level and a borderline near-significant difference (\(p=0.067\)) caused by the order of treatments. The interaction of the two factors was also significant (\(p=0.02\)). In the samples where pressure was the first treatment, the pressure level had less of an impact on the enthalpy values. When the sous-vide samples were pressurized, a decrease in denaturation heat was observed during the storage period. Changes in the protein structure were more important in the 300 MPa samples. However, the DSC denaturation heat (enthalpy) results should be examined together with the DSC thermograms (Figure 1a). The form of each peak or the absence of a peak gives additional information on the effect of each treatment. The differences between the heat and pressure treatment differences were clearly visible during the single-step treatments. The protein denaturation effects are still visible in the combined-treated samples but mainly at the lower (300 MPa) pressure level. The sous-vide heat treatment at 60 \({}^{\circ}\)C, combined with a pressure treatment of 600 MPa (both orders) led to a more intensely denatured protein set. While the heat + pressure-treated samples showed sensitivity to the pressure level (i.e., the higher the pressure, the stronger the effect), the pressure + heat treatment had similar curves at both pressure levels. Regarding the results of the combined treatments, we have to remark that the order of the treatments has a very important role concerning the protein content of the samples. The application of the heat treatment in combination with the pressure treatment still resulted in a partly denatured meat sample.