Antioxidant and angiotensin I-converting enzyme inhibitory activities of northern shrimp (Pandalus borealis) by-products hydrolysate by enzymatic hydrolysis

In the present study, we investigated to the antioxidant and angiotensin I-converting enzyme (ACE) inhibitory activities of the northern shrimp (Pandalus borealis) by-products (PBB) hydrolysates prepared by enzymatic hydrolysis. The antioxidant and ACE inhibitory activities of five enzymatic hydrolysates (alcalase, protamex, flavourzyme, papain, and trypsin) of PBB were evaluated by the 2, 2′-azino-bis [3-ethylbenzothiazoline-6-sulfonic acid] (ABTS) radical scavenging and superoxide dismutase (SOD)-like activities, reducing power and Li’s method for ACE inhibitory activity. Of these PBB hydrolysates, the protamex hydrolysate exhibited the most potent ACE inhibitory activity with IC50 value of 0.08 ± 0.00 mg/mL. The PBB protamex hydrolysate was fractionated by two ultrafiltration membranes with 3 and 10 kDa (below 3 kDa, between 3 and 10 kDa, and above 10 kDa). These three fractions were evaluated for the total amino acids composition, antioxidant, and ACE inhibitory activities. Among these fractions, the < 3 kDa and 3–10 kDa fractions showed more potent ABTS radical scavenging activity than that of > 10 kDa fraction, while the > 10 kDa fraction exhibited the significant reducing power than others. In addition, 3–10 kDa and > 10 kDa fractions showed the significant ACE inhibitory activity. These results suggested that the high molecular weight enzymatic hydrolysate derived from PBB could be used for control oxidative stress and prevent hypertension.