Antioxidant and angiotensin I-converting enzyme (ACE) inhibitory peptides of rainbow trout (Oncorhynchus mykiss) viscera hydrolysates subjected to simulated gastrointestinal digestion and intestinal absorption

Abstract

The objective of this work was to evaluate in vitro bioaccessibility, intestinal absorption, antioxidant and angiotensin I-converting enzyme (ACE) inhibitory activities of peptides from rainbow trout viscera hydrolysate (H). Rainbow trout Viscera (V) was hydrolyzed by Alcalase® 2.4L and a degree of hydrolysis (DH) of 44.8 ± 2.5% was achieved. Viscera and its hydrolysate were subjected to simulated gastrointestinal digestion (SGID) and intestinal absorption across Caco-2/TC7 cell monolayers. After the hydrolysis with Alcalase® 2.4L and the SGID of V, the species between 60.6 kDa and 13.0 kDa were decreased, causing an increase in species less than 6.51 kDa. The SGID of H did not modify the oxygen radical absorbance capacity (ORAC) or ACE inhibitory values but caused a significant decrease in the hydroxyl radical antioxidant capacity (HORAC) (30.2%). It also produced an increase in ABTS radical cation (ABTS assay) scavenging activity and ferric reducing antioxidant power (FRAP) (9.46% and 20.2%, respectively). Bioactive peptides in H were stable after SGID and they were partially able to cross Caco-2/TC7 cell monolayer, which demonstrates their possible intestinal absorption and their potential to act inside the organism.