## 3 Results and Discussion  
Comparison of the Effects of the Single Heat and Pressure Treatments Focusing on the Main Differences  
The results of the measurements on the single-step heat- or pressure-treated samples are presented in Table 3. Heat and pressure act differently on proteins. The differences between the single heat and pressure treatments are mainly derived from the different ways they modify the protein structure of the meat. The behavior of the different protein groups under heat or pressure treatment can be followed on DSC thermograms [49; 50; 51]. This dissimilarity is not explained by the measured enthalpy values alone, where no significant differences were observed between the treatments; also the form and pattern of the thermogram can characterize the single heat- or pressure-treated meat samples (Figure 1a). The raw pork sample has three dominant endothermic peaks: the myosin at around 49-52 \({}^{\circ}\)C, the sarcoplasm and connective tissue proteins at 56-58 \({}^{\circ}\)C, and the actin at 71-73 \({}^{\circ}\)C. The total measured enthalpy value was 3.09 J/g in the case of the raw pork sample, which has three well-distinguished peaks. These values correspond to the findings of our previous study where the myosin protein group was found at 50-55 \({}^{\circ}\)C (enthalpy value: 0.76 J/g), the sarcoplasm proteins and collagen at around 60-65 \({}^{\circ}\)C (enthalpy value: 1.31 J/g), and the actin at 70-75 \({}^{\circ}\)C (enthalpy value: 1.31 J/g), [51]. The sous-vide-treated sample showed a complete loss of the myosin peak, and only a partially modified collagen peak could be observed. In the case of high hydrostatic pressure treatment, the first observation was that the HHP treatment affected different protein groups than the heat treatment-induced  
Figure 1: DSC thermograms of the single-treated pork LTL muscle: (**a**) DSC thermograms of the combined heat and pressure-treated pork LTL muscle (**b**). denaturation. Above 200 MPa, denaturation can be seen on the myosin and actin groups, and their peak is modified, but in most cases, their complete loss can be observed. Below this pressure value, the treatment has practically no effect on the techno-functional properties of the meat samples [51; 52]. The collagen and sarcoplasmic proteins are still stable, and the pressure has only a slight effect on them. [PERSON] and [PERSON] [43] cite several studies reporting diverse changes even after a 100 MPa HHP treatment. Regarding weight loss, the heat-treated samples produce more important loss due to the shrinkage of myofibrils [53]. Weight loss values of the SV samples were not affected by storage temperature, while in the pressure-treated samples, higher weight loss values were observed. The higher the temperature, the more important the exudate. Contradicting these weight loss values (mainly water), moisture content does not show similar tendencies. Since [PERSON] and [PERSON] [46] proposed a simple and very effective technique to measure the water-holding capacity (WHC) of meat (the ability of meat to retain its natural water content), it has been extensively reviewed in several studies. Regarding the WHC values in our work (results not shown in this paper), we must conclude that samples where essentially different treatments were applied were not comparable due to the different weight losses induced by the treatments. This weight loss comprised mainly water, and these differences led to contradictions in the interpretation of the results (i.e., a sample that lost more weight--i.e., moisture/water--during the treatment resulted in a better WHC value, which is not necessarily an expression of the real water-holding parameter of the treated meat). The applied single sous-vide heat treatment at 60 \({}^{\circ}\)C and the 600 MPa pressure treatment resulted in a similar and slightly lighter color than the L* observed in the single 300 Mpa-treated sample. This value was stable with no significant change during the storage period.