Table 4.

ABTS and DPPH radical scavenging activities, reducing power (RP), Fe²⁺ and Cu²⁺ chelating activities, and ACE inhibitory activity of protein hydrolysates prepared from salmon heads (HPSs) and hake by-products (HPHs).

Sample	EC50/A0.5 * (mg/mL)
	ABTS	DPPH	RP *	Fe2+	Cu2+	ACE
HPS	2.4 ± 0.01 a	10.5 ± 0.04 b	25.5 ± 0.16 b	0.45 ± 0.04 a	n.a.	2.2 ± 0.13 b
HPH	2.1 ± 0.05 a	9.5 ± 0.10 a	20.1 ± 0.35 a	0.52 ± 0.02 b	0.64 ± 0.01	0.86 ± 0.05 a

n.a.—not achieved—50% inhibition was not achieved in the range of concentrations tested. * In the case of reducing power, A_0.5 was determined. Different letters in each column indicate significant differences (p < 0.05) between FPH.