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

Abstract

SummaryMicrowave 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 IC50 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.