Preparation, identification, and molecular docking of novel angiotensin‐converting enzyme inhibitory peptides derived from rice‐based distillers' spent cakes

Background

Rice‐based distillers' spent cake (RDSC), a by‐product of the Chinese liquor (Baijiu) industry, is a potential source of ACE inhibitory peptide. Since angiotensin‐converting enzyme (ACE) plays a crucial role in controlling hypertension, inhibition of ACE has been widely emphasized. The ACE inhibitory active peptide derived from by‐products of food has been recognized as safer and cheaper inhibitors.

Results

Aimed to discover ACE‐inhibiting active peptides in RDSC. Hydrolysis of RDSC by alcalase for 4 h followed by ultrafiltration yielded low‐molecular‐weight (< 3 kDa) fractions. Subsequently, a comprehensive method that using a combination of LC‐Q‐TOF‐MS and LC‐Q Exactive‐MS to identify the novel short‐ (3–5 amino acids residues; n = 7) and medium‐sized peptides (more than 6 amino acids residues; n = 6). In vitro activity assay showed that the peptides KPFFPGL, GFPRPLL, GPPGVF, and VGK exhibited the highest activity with IC₅₀ of 11.63, 12.34, 19.55, and 33.54 μM. Molecular docking reveal that the active and inactive sites (Glu123, Asp121, Arg522, and Lys118) play important roles in enhancing the ACE inhibitory activity of peptides.

Conclusion

Here we report a comprehensive method that effectively extracted and identified the bioactive peptides from RDSC. Four highly active novel peptides may be the most promising candidates for functional foods to against hypertension, provide significant information for enhancing value of rice‐based distilled by‐products.

This article is protected by copyright. All rights reserved.