Table 2.
Essential (EAA) and non-essential (NEAA) amino acids expressed in g/100 g dw sample (g/100 g protein) of hake by-products, salmon heads, and protein hydrolysates prepared from hake by-products (HPH) and salmon heads (HPS) by Alcalase hydrolysis.
| EAA | Hake By-Products | Salmon Heads | HPH | HPS |
|---|---|---|---|---|
| HIS | 1.33 ± 0.10 b (1.70 ± 0.13) A |
0.58 ± 0.10 a (1.63 ± 0.27) A |
0.75 ± 0.15 a,b (0.97 ± 0.20) A |
1.06 ± 0.37 a,b (1.40 ± 0.48) A |
| LYS | 5.68 ± 1.67 a (7.30 ± 2.15) A |
3.38 ± 0.46 a (9.51 ± 1.30) A |
6.24 ± 0.61 a (8.12 ± 0.80) A |
6.09 ± 0.92 a (8.05 ± 1.22) A |
| LEU | 5.95 ± 0.05 d (7.64 ± 0.06) A |
2.22 ± 0.25 a (6.25 ± 0.70) B |
5.42 ± 0.11 c (7.05 ± 0.14) A,B |
4.60 ± 0.02 b (6.08 ± 0.02) B |
| VAL | 3.75 ± 0.22 c (4.81 ± 0.28) A |
1.53 ± 0.12 a (4.30 ± 0.33) A |
3.43 ± 0.03 b,c (4.46 ± 0.04) A |
3.13 ± 0.03 b (4.13 ± 0.04) A |
| MET | 1.90 ± 0.50 b (2.44 ± 0.64) A |
0.47 ± 0.08 a
(1.31 ± 0.21) A |
1.56 ± 0.08 b
(2.02 ± 0.10) A |
1.44 ± 0.11 b (1.91 ± 0.15) A |
| CYS | 0.79 ± 0.07 b
(1.01 ± 0.08) B |
0.51 ± 0.06 a (1.44 ± 1.18) A |
0.89 ± 0.03 b (1.16 ± 0.04) A,B |
1.05 ± 0.01 c (1.39 ± 0.02) A |
| PHE | 3.13 ± 0.17 c (4.02 ± 0.21) A |
1.21 ± 0.13 a (3.39 ± 0.36) A,B |
2.89 ± 0.06 c (3.76 ± 0.07) A,B |
2.47 ± 0.06 b (3.27 ± 0.08) B |
| TYR | 2.69 ± 0.16 c
(3.45 ± 0.21) A |
1.05 ± 0.10 a (2.94 ± 0.29) A,B |
2.42 ± 0.04 c
(3.15 ± 0.05) A,B |
2.06 ± 0.06 b
(2.73 ± 0.08) B |
| ILE | 3.40 ± 0.24 c (4.37 ± 0.30) A |
1.28 ± 0.12 a (3.58 ± 0.34) B |
2.93 ± 0.07 b (3.81 ± 0.10) A,B |
2.60 ± 0.02 b
(3.44 ± 0.03) B |
| THR | 4.03 ± 0.24 b
(5.18 ± 0.31) A |
1.93 ± 0.20 a
(5.41 ± 0.57) A |
4.02 ± 0.01 b
(5.23 ± 0.01) A |
3.53 ± 0.13 b (4.67 ± 0.18) A |
| NEAA | ||||
| ASP | 8.16 ± 0.33 c
(10.48 ± 0.42) A |
3.22 ± 0.34 a
(9.05 ± 0.95) A |
7.57 ± 0.15 b,c
(9.86 ± 0.20) A |
6.80 ± 0.09 b
(8.98 ± 0.12) A |
| GLU | 12.96 ± 0.55 c
(16.64 ± 0.70) A |
4.79 ± 0.50 a
(13.44 ± 1.40) B |
12.11 ± 0.22 c
(15.76 ± 0.28) A,B |
10.12 ± 0.12 b
(13.38 ± 0.17) B |
| ASN | <QL (<QL) |
<QL (<QL) |
<QL (<QL) |
<QL (<QL) |
| SER | 3.52 ± 0.15 b
(4.52 ± 0.10) A |
1.49 ± 0.19 a
(4.17 ± 0.54) A |
3.50 ± 0.07 b (4.55 ± 0.09) A |
3.14 ± 0.10 b (4.15 ± 0.13) A |
| GLN | <QL (<QL) |
<QL (<QL) |
<QL (<QL) |
<QL (<QL) |
| GLY | 4.14 ± 0.05 a
(5.31 ± 0.07) C |
3.27 ± 0.53 a (9.17 ± 1.49) A,B |
5.47 ± 0.12 b
(7.12 ± 0.16) B,C |
7.31 ± 0.15 c
(9.66 ± 0.20) A |
| ARG | 4.86 ± 0.16 b (6.24 ± 0.20) A |
2.21 ± 0.26 a
(6.22 ± 0.74) A |
4.74 ± 0.12 b
(6.17 ± 0.15) A |
4.58 ± 0.14 b (6.05 ± 0.19) A |
| ALA | 4.98 ± 0.19 b (6.39 ± 0.25) A |
2.42 ± 0.25 a (6.80 ± 0.70) A |
5.16 ± 0.03 b (6.72 ± 0.04) A |
5.25 ± 0.11 b (6.94 ± 0.15) A |
| Tau | <QL (<QL) |
<QL (<QL) |
<QL (<QL) |
<QL (<QL) |
| PRO | 3.11 ± 0.41 b
(3.99 ± 0.53) A |
1.80 ± 0.22 a (5.05 ± 0.61) A |
3.49 ± 0.10 b (4.54 ± 0.13) A |
3.91 ± 0.36 b
(5.17 ± 0.48) A |
| HYP | <QL (<QL) |
0.42 ± 0.07 a
(1.19 ± 0.19) A |
<QL (<QL) |
1.00 ± 0.03 b
(1.32 ± 0.04) A |
| Total AA (g/100 g) | 74.38 | 33.77 | 72.57 | 70.14 |
Different letters in each line indicate significant differences (p < 0.05) for each amino acid. QL—quantification limit.