Enzymatic production of protein hydrolysates from steelhead (Oncorhynchus mykiss) skin gelatin as inhibitors of dipeptidyl-peptidase IV and angiotensin-I converting enzyme

Abstract

The objective of this study was to generate protein hydrolysates with dual in vitro inhibitory activities against dipeptidyl-peptidase IV (DPP-IV) and angiotensin-I converting enzyme (ACE), by proteolytic enzymes acting either individually or sequentially on steelhead skin gelatin. The results showed strong dual bioactivity in the low molecular weight (< 3 kDa) fractions obtained by ultrafiltration of hydrolysates produced using the enzymes pepsin, CorolaseN or papain. Alternatively, unfractionated hydrolysates exhibiting high ACE and DPP-IV inhibitory activities as well as yields could be attained by strategic selection of two enzymes for successive hydrolysis of gelatin. In particular, hydrolysates produced using 4% papain for 2 h followed either by ultrafiltration or by a second hydrolysis with 1% CorolaseN for 2 h, presented potent dual activity as ACE and DPP-IV inhibitors, and should be investigated further as potential functional food ingredients or nutraceuticals for the management of hypertension and diabetes.

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

“…As reported in Table , protein hydrolysates (FPE) at a concentration of 5 mg mL −1 exhibited a strong activity against ACE (93.48 ± 0.24%), while the antihypertensive drug, captopril, showed 99.45 ± 0.01% inhibition at all concentration used (1.25 to 5 mg mL −1 ). It is suggested that peptides with ACE‐inhibitory activity are generated during hydrolysis (Cheung & Li‐Chan, ). Inhibition activity was concentration‐dependent as the values increased with increasing hydrolysate concentration from 1.25 to 5 mg mL −1 , with an IC 50 = 0.015 mg mL −1 for FPE.…”

“…Both ACE and DPP‐IV inhibitory activities are often reported to be associated with lower molecular weight peptides (Iwaniak et al ., ; Power et al ., ). For example, Cheung & Li‐Chan () showed that <3 kDa fractions had better ACE and DPP‐IV inhibitory activities than unfractionated steelhead skin‐gelatin hydrolysates. Based on these findings, the EDUF system used in this study can be a suitable process for delivering fractions containing specific bioactive peptides.…”

“…Recent scientific research has focused on converting by‐products into protein hydrolysates through enzymatic treatments with subsequent screening for bioactive peptides (He et al ., ; Ketnawa & Liceaga, ; Nguyen et al ., ; Suwal et al ., ). For example, peptides with ACE and DPP‐IV inhibitory activity were obtained from rainbow (steelhead) trout skin‐gelatin (Cheung & Li‐Chan, ) and salmon ( Salmo salar ) trimmings (Neves et al ., ), proposing their application as functional ingredients for controlling hypertension and type‐2 diabetes.…”

Biological activity of peptides purified from fish skin hydrolysates

“…Ultrafiltration of steelhead/rainbow hydrolysates yielded fractions of less than 3 kDa with ACE inhibitory activity higher than the activity of the whole hydrolysates (Cheung and Li-Chan 2017). The low MW fractions were prepared from whole hydrolysates using commercial enzyme kits.…”

“…Antihyperglycemic activity of fish skin was evaluated using dipeptidyl peptidase IV (DPP-IV) inhibitory assay. Steelhead (Oncorhynchus mykiss) skin gelatin hydrolysates were prepared, and the hydrolysate of 4% papain had the highest DPP-IV inhibitory activity 40-45% (Cheung and Li-Chan 2017). The hydrolysates were purified with ultrafiltration to obtain fraction of less than 3 kDa.…”