## 3 Results and Discussion
### Antioxidant Activity
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sample** & **Fraction** & **FRAP [U]** & **TEAC [U]** & **DPPH [U]** \\ \hline \multirow{3}{*}{Meat, 2 \({}^{\circ}\)C} & Unfractionated & 34.9 \(\pm\) 3.9 ab & 135.7 \(\pm\) 1.8 a & 281.1 \(\pm\) 2.2 f \\  & \(>\)10 kDa & 4.0 \(\pm\) 0.0 k & 8.6 \(\pm\) 0.2 o & 38.3 \(\pm\) 1.7 m \\  & 5–10 kDa & 20.3 \(\pm\) 1.4 d & 78.5 \(\pm\) 3.7 d & 70.7 \(\pm\) 3.9 k \\  & \(<\)5 kDa & 10.9 \(\pm\) 0.9 i & 64.9 \(\pm\) 5.1 f & 168.5 \(\pm\) 9.7 h \\ \hline \multirow{3}{*}{Meat, 7 \({}^{\circ}\)C} & Unfractionated & 30.4 \(\pm\) 0.8 bc & 106.9 \(\pm\) 5.3 c & 312.7 \(\pm\) 18.1 e \\  & \(>\)10 kDa & 4.6 \(\pm\) 0.5 j & 13 \(\pm\) 0.8 n & 22.6 \(\pm\) 1.4 P \\  & 5–10 kDa & 26.4 \(\pm\) 3.2 c & 61.9 \(\pm\) 4.7 f & 35.2 \(\pm\) 0.5 o \\  & \(<\)5 kDa & 10.5 \(\pm\) 3.0 i & 55.7 \(\pm\) 3.8 g & 113.7 \(\pm\) 12.3 i \\ \hline \multirow{3}{*}{Meat, 12 \({}^{\circ}\)C} & Unfractionated & 33.7 \(\pm\) 2.0 a & 124.2 \(\pm\) 3.8 b & 251.5 \(\pm\) 14.3 g \\  & \(>\)10 kDa & 4.3 \(\pm\) 0.1 j & 6.9 \(\pm\) 0.1 P & 36.2 \(\pm\) 0.1 n \\  & 5–10 kDa & 13.3 \(\pm\) 1.5 ghi & 60.5 \(\pm\) 3.2 f & 41 \(\pm\) 3.9 m \\  & \(<\)5 kDa & 16.1 \(\pm\) 0.9 f & 71.1 \(\pm\) 4.1 deg & 138.9 \(\pm\) 17.4 j \\ \hline \multirow{3}{*}{Brine, 2 \({}^{\circ}\)C} & Unfractionated & 31.2 \(\pm\) 1.3 ab & 35.7 \(\pm\) 0.1 i & 615.5 \(\pm\) 38.9 b \\  & \(>\)10 kDa & 1.8 \(\pm\) 0.0 l & 1.7 \(\pm\) 0.0 r & 35.2 \(\pm\) 1.2 no \\  & 5–10 kDa & 15.7 \(\pm\) 0.9 f & 29.3 \(\pm\) 0.8 k & 128.6 \(\pm\) 7.8 j \\  & \(<\)5 kDa & 14.1 \(\pm\) 0.4 h & 24.0 \(\pm\) 0.9 m & 325.3 \(\pm\) 22.4 e \\ \hline \multirow{3}{*}{Brine, 7 \({}^{\circ}\)C} & Unfractionated & 26.6 \(\pm\) 1.5 c & 34.3 \(\pm\) 0.3 j & 638.4 \(\pm\) 19.3 b \\  & \(>\)10 kDa & 1.6 \(\pm\) 0.1 l & 1.5 \(\pm\) 0.0 s & 57.3 \(\pm\) 5.4 l \\ \cline{1-1}  & 5–10 kDa & 15.5 \(\pm\) 0.6 f & 27.4 \(\pm\) 0.9 l & 121.3 \(\pm\) 1.3 j \\ \cline{1-1}  & \(<\)5 kDa & 17.6 \(\pm\) 1.0 e & 27.5 \(\pm\) 0.9 l & 410.6 \(\pm\) 15.5 c \\ \hline \multirow{3}{*}{Brine, 12 \({}^{\circ}\)C} & Unfractionated & 29.1 \(\pm\) 1.0 bc & 36.6 \(\pm\) 0.1 h & 679.9 \(\pm\) 15.3 a \\ \cline{1-1}  & \(>\)10 kDa & 1.8 \(\pm\) 0.1 l & 1.5 \(\pm\) 0.0 s & 12.8 \(\pm\) 1.2 r \\ \cline{1-1}  & 5–10 kDa & 20.3 \(\pm\) 0.7 d & 34.9 \(\pm\) 0.9 g & 372.5 \(\pm\) 9.3 d \\ \cline{1-1}  & \(<\)5 kDa & 18.3 \(\pm\) 1.3 deg & 27.8 \(\pm\) 1.5 kl & 392 \(\pm\) 8.8 c \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Antioxidant activity of ISP extracts from meat and brine before (unfractionated) and after fractionation (\(>\)10, 5–10, and \(<\)5 kDa); \({}^{\circ}\)–ps means within the same column with different lowercase letters differing significantly. in the brine before fractionation. This may be due to (i) the release of substances with antioxidant properties, similar to the phenomenon of cathepsin release from lysosomes [5]; (ii) the removal of enzymes with oxidative activity [17], which remained in the >10 kDa fraction and reduced its activity almost completely (Table 6); and/or (iii) an increase in the synergistic effect of individual peptides after purification/fractionation. A synergistic effect, and a 68% increase in antioxidant activity, was also described for the cod hydrolysate and its RP-HPLC fractions [46]. The free-radical-scavenging capacity of the unfractionated ISP extract and its UF fractions were also tested by their ability to scavenge the stable DPPH radical. The DPPH radical scavenging activity in the meat was 251.5-312.7 uM TE/100 g, while in the brine, it was 615.5-679.9 uM TE/100 ml. (Table 6). The highest DPPH activity was using marination at 7 \({}^{\circ}\)C for the meat, and 12 \({}^{\circ}\)C for the brine. The DPPH activity in the meat consisted mainly of the <5 kDa fraction, while in the brine, in addition to the <5 kDa fraction, the 5-10 kDa fraction contributed significantly, especially as the marinating temperature became higher.