## 3 Results and Discussion
### Effect of HP on the Sensorial Characteristics of Fish Filllets  
The sea bass fillets were evaluated both raw and cooked in order to investigate the effect of HP treatment on selected sensorial attributes of the samples. Regarding the case of raw untreated and raw HP-treated fillets, the samples were presented to the panelists as a ready-to-cook product. Results indicated that the application of HP at pressures above 100 MPa led to fish fillets with a significantly lighter surface and consequently lower scores for color and appearance (as they were evaluated on a hedonic scale). However, they did not reach unacceptable levels (set level of acceptance: 5), at least at the beginning of the storage period (Figure 5a). However, it is worth noting that at the end of the storage period, both the untreated samples and those treated at 100 MPa exhibited the most intense changes in terms of appearance and color when compared to samples treated at pressures above 200 MPa, which achieved similar results throughout the storage period (Figure 5b). Moreover, the latter samples exhibited the least changes regarding odor, maintaining it above acceptable levels until the end of their shelf life. This might be attributed to the bacterial mitigation after HP processing and consequently to the inhibited production of off-odor products, e.g., trimethylamine, biogenic amines, and volatile nitrogen, leading to odor stability and an improved consumer acceptability of the HP-treated fish products [40]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Fish Fillet Treatment** & **Lipid Oxidation Rate \({}^{\ast}\) (d\({}^{-1}\))** & **Lag Phase (d)** & **R-Square** & **Shelf Life \({}^{\ast\ast}\) (d)** \\ \hline Untreated fillet & 0.104 \({}^{\circ}\) (\(\pm\)0.011) & - & _0.957_ & 9.67 \({}^{\text{a}}\) (\(\pm\)1.03) \\
100 MPa\_25 \({}^{\circ}\)C\_10 min & 0.050 \({}^{\text{b}}\) (\(\pm\)0.005) & - & _0.950_ & 20.3 \({}^{\text{b}}\) (\(\pm\)2.11) \\
200 MPa\_25 \({}^{\circ}\)C\_10 min & 0.042 \({}^{\text{ab}}\) (\(\pm\)0.004) & - & _0.949_ & 23.8 \({}^{\text{c}}\) (\(\pm\)2.26) \\
300 MPa\_25 \({}^{\circ}\)C\_10 min & 0.048 \({}^{\text{b}}\) (\(\pm\)0.003) & 6.08 \({}^{\text{a}}\) (\(\pm\)1.76) & _0.989_ & 27.0 \({}^{\text{d}}\) (\(\pm\)1.14) \\
400 MPa\_25 \({}^{\circ}\)C\_10 min & 0.036 \({}^{\text{a}}\) (\(\pm\)0.002) & 5.85 \({}^{\text{a}}\) (\(\pm\)1.99) & _0.979_ & 34.0 \({}^{\text{e}}\) (\(\pm\)1.82) \\ \hline \hline \end{tabular}  
* As estimated using linear regression. \({}^{\ast\ast}\) Acceptable limit: 1 mg MDA/kg product. Values are means \(\pm\) standard error of regression. Different lowercase letters in the same column indicate significant difference (_p_ < 0.05) between tested samples according to [PERSON]’s mean values post hoc comparison test.  
\end{table} 
Table 4: Kinetic parameters of TBARs development for different treated sea bass fillets aerobically stored. Figure 6 presents the overall acceptability scores for untreated and HP-treated fish samples, with the latter being treated at different pressure levels and at an ambient temperature for 10 min as it was observed that both the processing temperature and time had no effect on the sensorial characteristics of the fillets. This is in agreement with previous studies in which no effect of temperature and processing time was observed on the sensorial attributes of cold smoked salmon and fresh gilthead sea bream stored at 2 \({}^{\circ}\)C after undergoing HP treatment at 220, 250, and 330 MPa at 3-25 \({}^{\circ}\)C for 5 and 10 min [17; 29].