Table 2.

Composition and contents of amino acids in the fish skin, collagen from fish skin and the hydrolysates prepared at different scales.

Amino acid	Fish skin (g/100 g)	Collagens from fish skin (g/100 g)	Laboratory scale (g/100 g)	Pilot scale (g/100 g)	Plant scale (g/100 g)
Ala	5.83 ± 1.55	8.29 ± 1.43	6.56 ± 0.63	7.25 ± 2.06	9.07 ± 1.21
Arg	9.57 ± 0.24	7.58 ± 0.31	8.72 ± 0.03	7.77 ± 0.92	8.96 ± 0.11
Asna	—	—	—	—	—
Asp	7.38 ± 0.31	6.03 ± 0.18	5.54 ± 0.19	5.83 ± 0.33	5.53 ± 0.19
Cysb	—	—	—	—	—
Glna	—	—	—	—	—
Glu	12.33 ± 0.44	10.67 ± 0.24	9.89 ± 0.07	10.31 ± 0.41	10.10 ± 0.21
Gly	14.82 ± 0.79	22.30 ± 0.34	22.85 ± 0.18	21.98 ± 0.38	21.73 ± 0.33
His	1.27 ± 0.10	0.93 ± 0.03	0.91 ± 0.02	0.94 ± 0.07	0.79 ± 0.03
Ile*	1.73 ± 0.13	1.03 ± 0.04	0.93 ± 0.02	1.05 ± 0.01	0.92 ± 0.04
Leu*	3.62 ± 0.22	2.19 ± 0.04	1.86 ± 0.02	2.10 ± 0.05	2.06 ± 0.06
Lys*	4.59 ± 0.33	3.07 ± 0.09	3.01 ± 0.06	3.21 ± 0.27	3.03 ± 0.08
Met*	1.16 ± 0.06	0.72 ± 0.09	0.77 ± 0.04	0.93 ± 0.19	0.54 ± 0.04
Phe*	4.93 ± 0.26	6.13 ± 0.18	6.46 ± 0.27	6.14 ± 0.21	5.75 ± 0.26
Pro	6.68 ± 0.17	8.79 ± 0.03	8.53 ± 0.07	8.43 ± 0.33	7.92 ± 0.09
Ser	4.82 ± 0.23	5.01 ± 0.14	4.85 ± 0.08	4.82 ± 0.33	4.47 ± 0.14
Thr*	3.81 ± 0.20	3.03 ± 0.08	2.61 ± 0.07	2.74 ± 0.04	2.82 ± 0.09
Trp*,a	—	—	—	—	—
Tyr	3.64 ± 0.10	1.70 ± 0.95	2.20 ± 0.10	2.53 ± 0.16	2.99 ± 0.35
Val*	2.53 ± 0.15	1.62 ± 0.04	1.44 ± 0.03	1.52 ± 0.17	1.41 ± 0.01
Hypro	5.49 ± 0.11	8.33 ± 0.28	8.01 ± 0.24	7.80 ± 0.50	8.09 ± 0.49
Hylys	0.38 ± 0.04	0.53 ± 0.02	0.48 ± 0.02	0.53 ± 0.02	0.59 ± 0.03
Total	94.58 ± 5.43	97.95 ± 4.51	95.62 ± 2.14	95.88 ± 6.45	96.77 ± 3.76

*Human-essential amino acids.

^aNot detectable because they were destroyed in the process of acid hydrolysis.

^bNot detectable because of its low content in collagen.

—Not detectable.