Table 4.

Antioxidant activities of tuna skin collagen, gelatin, and their hydrolysates.

Samples	IC50 (µg protein/mL)
	ABTS	DPPH
Collagen	313.29 ± 0.15 f	560.51 ± 0.02 g
Hydrolyzed collagen	66.28 ± 0.12 e	119.10 ± 0.01 f
Peptides >30 kDa	64.47 ± 0.13 e	101.77 ± 0.01 f
Peptides 10–30 kDa	33.02 ± 0.05 cd	83.22 ± 0.01 de
Peptides 3–10 kDa	29.24 ± 0.02 c	75.94 ± 0.01 d
Peptides <3 kDa	35.39 ± 0.07 d	82.12 ± 0.02 de
Gelatin	62.21 ± 0.01 e	654.62 ± 0.03 g
Hydrolyzed gelatin	16.28 ± 0.01 b	78.87 ± 0.01 d
Peptides >30 kDa	19.17 ± 0.01 b	84.15 ± 0.01 e
Peptides 10–30 kDa	9.11 ± 0.01 a	15.12 ± 0.01 a
Peptides 3–10 kDa	17.06 ± 0.01 b	50.04 ± 0.01 c
Peptides <3 kDa	11.20 ± 0.01 ab	23.80 ± 0.01 b

Note: Different superscripts in the same column show significant differences (p < 0.05).