## 3 Results and Discussion
### Instrumental Texture Analysis
#### 3.6.2 Texture Profile Analysis (TPA)  
TPA delivers more information on the texture of meat products than shear force which in turn is a useful indicator of initial meat tenderness [48].  
Texture profile attributes are presented in Table 3. The treatment temperature that resulted in the lowest hardness was 60 \({}^{\circ}\)C, and the values declined with prolonged cooking time from 60.26 N to 54.77 N. Comparable hardness was observed for the samples cooked at 65 \({}^{\circ}\)C for 3 or 4 h and at 70 \({}^{\circ}\)C for 1 h. In general, the higher the cooking temperature, the higher the hardness of samples noted. Similar increases with increased temperature of process were observed in other texture attributes of samples. It is worth noting that at 60 and 65 \({}^{\circ}\)C, hardness and chewiness values tended to decline with prolonged cooking time, while the opposite tendency occurred at 70 and 75 \({}^{\circ}\)C. This observation presumably could be explained by the relatively mild myofibrillar protein denaturation at lower temperatures and increasing collagen hydrolyzation with prolonged cooking time while at higher temperatures the changes in myofibrillar proteins predominated, leading to increased meat toughness. Likewise in the case of shear force, temperature and time of treatment influenced meat hardness significantly (\(p<0.001\)), but not their interaction. Other texture attributes were affected by temperature and cooking time as well as their interaction.  
\begin{table}
\begin{tabular}{l l l l l l} \hline \hline \multicolumn{1}{c}{**Sample**} & \multicolumn{1}{c}{**Shear Force [N]**} & \multicolumn{1}{c}{**Hardness [N]**} & \multicolumn{1}{c}{**Springiness [cm]**} & \multicolumn{1}{c}{**Cohesiveness [-]**} & \multicolumn{1}{c}{**Chewiness [N \(\times\) cm]**} \\ \hline
60 \({}^{\circ}\)C & & & & & & \\  & 2 h & 23.80 \(\pm\) 0.95  & 60.26 \(\pm\) 3.33  & 0.50 \(\pm\) 0.01  & 0.56 \(\pm\) 0.01  & 17.51 \(\pm\) 0.01  \\  & 3 h & 17.63 \(\pm\) 1.70  & 58.84 \(\pm\) 3.67  & 0.46 \(\pm\) 0.01  & 0.51 \(\pm\) 0.01  & 16.00 \(\pm\) 0.01  \\  & 4 h & 25.61 \(\pm\) 0.68  & 54.77 \(\pm\) 4.19  & 0.46 \(\pm\) 0.02  & 0.51 \(\pm\) 0.02  & 13.65 \(\pm\) 0.01  \\ \hline
65 \({}^{\circ}\)C & & & & & \\  & 2 h & 18.24 \(\pm\) 1.39  & 79.29 \(\pm\) 4.06  & 0.53 \(\pm\) 0.01  & 0.57 \(\pm\) 0.01  & 24.01 \(\pm\) 0.01  \\  & 3 h & 13.29 \(\pm\) 1.01  & 71.12 \(\pm\) 4.23  & 0.51 \(\pm\) 0.01  & 0.59 \(\pm\) 0.01  & 21.19 \(\pm\) 0.01  \\  & 4 h & 19.95 \(\pm\) 0.52  & 72.91 \(\pm\) 2.85  & 0.45 \(\pm\) 0.01  & 0.52 \(\pm\) 0.01  & 17.34 \(\pm\) 0.01  \\ \hline
70 \({}^{\circ}\)C & & & & & \\  & 1 h & 22.47 \(\pm\) 1.30  & 69.20 \(\pm\) 2.22  & 0.52 \(\pm\) 0.01  & 0.60 \(\pm\) 0.00  & 21.32 \(\pm\) 0.01  \\  & 1.5 h & 18.40 \(\pm\) 1.19  & 90.11 \(\pm\) 3.46  & 0.49 \(\pm\) 0.01 [PERSON] et al. [21] noted lower hardness and chewiness of pork ham sous vide cooked at 61 \({}^{\circ}\)C and 71 \({}^{\circ}\)C for 45 and 90 min, compared to the control samples boiled in a pot for 45 min. [PERSON] et al. [3] did not observe any significant effect of cooking at 60 \({}^{\circ}\)C for 5 or 12 h on texture attributes of pork cheeks, while during treatment at 80 \({}^{\circ}\)C, increasing cooking time from 5 to 12 h caused a decline in these parameters. These finding were supported by the histological analyses which showed a bigger formation of completely denatured collagen fibres of the samples cooked at 80 \({}^{\circ}\)C than at 60 \({}^{\circ}\)C. [PERSON] et al. [53] observed collagen shrinkage at 57 \({}^{\circ}\)C and collagen denaturation between 59 \({}^{\circ}\)C and 61 \({}^{\circ}\)C. [PERSON] et al. [54] ascribed a lower hardness, cohesiveness and chewiness of beef cooked at 60 \({}^{\circ}\)C than at 70 or 80 \({}^{\circ}\)C to the myosin and actin denaturation (at 40-60 \({}^{\circ}\)C and 66-73 \({}^{\circ}\)C, respectively) and shrinking of collagen (56-62 \({}^{\circ}\)C), which might as well be an explanation of observations made in the present study.