Selective separation and characterisation of dual <scp>ACE</scp> and <scp>DPP</scp>‐<scp>IV</scp> inhibitory peptides from rainbow trout (<i>Oncorhynchus mykiss</i>) protein hydrolysates

Abstract

Summary Microwave pretreatment and hydrolysis were applied to rainbow trout ( Oncorhynchus mykiss ) by‐products to produce bioactive peptides with dual in vitro angiotensin‐I converting enzyme ( ACE ) and dipeptidyl‐peptidase IV ( DPP ‐ IV ) inhibitory activities. Peptides were fractionated using the single step electrodialysis with ultrafiltration membrane ( EDUF ). Concentration of cationic peptides ( CP ) increased in the recovery solution, reaching 125 μg mL −1 after a 4‐h treatment with migration rate of 15.68 ± 2.98 g m −2 h. CP fractions displayed ACE and DPP ‐ IV I inhibitory properties, with IC 50 values of 0.0036 mg mL −1 and 1.23 mg mL −1 respectively. The bioactivity was attributed to the low molecular weight peptides (300–500 Da) recovered. CP exhibited non‐competitive inhibition patterns for ACE and DPP ‐ IV , which were dose dependent. These results showed that bioactive peptides can successfully be separated from complex hydrolysate mixtures by EDUF . The fractionated peptides can serve as potential functional food ingredients or nutraceuticals for the management of hypertension and diabetes.