## 3 Results and Discussion
### Amino Acid and Peptide Profile
#### 3.2.2 Peptide Profile
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Essential** & **CONC1** & **CONC2** & **CONC3** & **HYDR1** & **HYDR2** & **COLL1** \\ \hline His & \textless{}0.18 & \textless{}0.18 & \textless{}0.18 & 2.12 \(\pm\) 0.34 \({}^{\text{a}}\) & 0.63 \(\pm\) 0.1 \({}^{\text{b}}\) & \textless{}0.18 \\ [PERSON] & \textless{}0.18 & \textless{}0.18 & \textless{}0.18 & 7.4 \(\pm\) 0.74 \({}^{\text{a}}\) & 0.61 \(\pm\) 0.06 \({}^{\text{b}}\) & \textless{}0.18 \\ [PERSON] & 0.19 \(\pm\) 0.02 \({}^{\text{a}}\) & \textless{}0.08 & 0.1 \(\pm\) 0.01 \({}^{\text{a}}\) & 26 \(\pm\) 2.08 \({}^{\text{b}}\) & 2.46 \(\pm\) 0.2 \({}^{\text{c}}\) & \textless{}0.08 \\ Lys & 0.3 \(\pm\) 0.05 \({}^{\text{a}}\) & 0.13 \(\pm\) 0.02 \({}^{\text{a}}\) & 0.14 \(\pm\) 0.02 \({}^{\text{a}}\) & 9.31 \(\pm\) 1.49 \({}^{\text{b}}\) & 1.15 \(\pm\) 0.18 \({}^{\text{a}}\) & \textless{}0.07 \\ Met & \textless{}0.08 & \textless{}0.08 & \textless{}0.08 & 7.86 \(\pm\) 0.63 \({}^{\text{a}}\) & 0.59 \(\pm\) 0.05 \({}^{\text{b}}\) & \textless{}0.08 \\ Phe & \textless{}0.16 & \textless{}0.16 & \textless{}0.16 & 12.7 \(\pm\) 1.78 \({}^{\text{a}}\) & 0.77 \(\pm\) 0.11 \({}^{\text{b}}\) & \textless{}0.16 \\ Thr & \textless{}0.03 & 0.07 \(\pm\) 0.01 \({}^{\text{a}}\) & \textless{}0.03 & 5.51 \(\pm\) 0.55 \({}^{\text{b}}\) & 0.5 \(\pm\) 0.05 \({}^{\text{a}}\) & \textless{}0.03 \\ Trp & \textless{}0.1 & \textless{}0.1 & \textless{}0.1 & 1.94 \(\pm\) 0.19 \({}^{\text{a}}\) & 0.16 \(\pm\) 0.02 \({}^{\text{b}}\) & \textless{}0.1 \\ Val & 0.1 \(\pm\) 0.01 \({}^{\text{a}}\) & \textless{}0.08 & 0.09 \(\pm\) 0.01 \({}^{\text{a}}\) & 10.5 \(\pm\) 1.26 \({}^{\text{b}}\) & 1.12 \(\pm\) 0.13 \({}^{\text{a}}\) & \textless{}0.08 \\ \hline \multicolumn{6}{c}{Non-Essential} \\ \hline Ala & 0.37 \(\pm\) 0.03 \({}^{\text{a}}\) & 0.24 \(\pm\) 0.02 \({}^{\text{a}}\) & 0.47 \(\pm\) 0.04 \({}^{\text{a}}\) & 9.43 \(\pm\) 0.75 \({}^{\text{b}}\) & 1.46 \(\pm\) 0.12 \({}^{\text{c}}\) & 0.14 \(\pm\) 0.01 \({}^{\text{a}}\) \\ Arg & 0.25 \(\pm\) 0.03 \({}^{\text{a}}\) & 0.08 \(\pm\) 0.01 \({}^{\text{a}}\) & 0.05 \(\pm\) 0.01 \({}^{\text{a}}\) & 14.1 \(\pm\) 1.41 \({}^{\text{b}}\) & 1.09 \(\pm\) 0.11 \({}^{\text{a}}\) & \textless{}0.05 \\ Asp & \textless{}0.09 & \textless{}0.09 & \textless{}0.09 & 2.47 \(\pm\) 0.22 \({}^{\text{a}}\) & 0.79 \(\pm\) 0.07 \({}^{\text{b}}\) & 0.2 \(\pm\) 0.02 \({}^{\text{c}}\) \\ Glu & \textless{}0.11 & \textless{}0.11 & \textless{}0.11 & 6.26 \(\pm\) 0.44 \({}^{\text{a}}\) & 2.14 \(\pm\) 0.15 \({}^{\text{b}}\) & \textless{}0.11 \\ Gly & 0.31 \(\pm\) 0.03 \({}^{\text{a}}\) & 0.18 \(\pm\) 0.02 \({}^{\text{a}}\) & 0.3 \(\pm\) 0.03 \({}^{\text{ab}}\) & 1.74 \(\pm\) 0.16 \({}^{\text{c}}\) & 0.66 \(\pm\) 0.06 \({}^{\text{d}}\) & 0.43 \(\pm\) 0.04 \({}^{\text{b}}\) \\ Tau & 3.05 \(\pm\) 0.31 \({}^{\text{a}}\) & 1.71 \(\pm\) 0.17 \({}^{\text{b}}\) & 4.41 \(\pm\) 0.44 \({}^{\text{c}}\) & 5.9 \(\pm\) 0.59 \({}^{\text{d}}\) & 3.02 \(\pm\) 0.3 \({}^{\text{a}}\) & \textless{}0.09 \\ Orn & \textless{}0.1 & \textless{}0.1 & \textless{}0.1 & \textless{}0.1 & 0.18 \(\pm\) 0.02 & \textless{}0.1 \\ Pro & \textless{}0.1 & 0.14 \(\pm\) 0.01 & \textless{}0.1 & \textless{}0.1 & \textless{}0.1 & \textless{}0.1 \\ Ser & \textless{}0.08 & \textless{}0.08 & \textless{}0.08 & 4.52 \(\pm\) 0.5 \({}^{\text{a}}\) & 0.68 \(\pm\) 0.07 \({}^{\text{b}}\) & \textless{}0.08 \\ Tyr & \textless{}0.12 & \textless{}0.12 & \textless{}0.12 & 7.03 \(\pm\) 1.27 \({}^{\text{a}}\) & 0.6 \(\pm\) 0.11 \({}^{\text{b}}\) & \textless{}0.12 \\ Cys & \textless{}0.07 & 0.11 \(\pm\) 0.02 \({}^{\text{a}}\) & \textless{}0.07 & 5.71 \(\pm\) 0.91 \({}^{\text{b}}\) & 1.74 \(\pm\) 0.28 \({}^{\text{c}}\) & \textless{}0.07 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Free amino acids (\(\mu\)g/g) in commercial fish protein concentrates, hydrolysates, and hydrolyzed collagen with mean and standard deviation of three replicate measurements. Different letters within the same row indicate a statistically significant difference with ANOVA post hoc pair comparison (\(p<0.05\)). raw material.