Effect of processing conditions and simulated gastrointestinal digestion on the activity of angiotensin I-converting enzyme (ACE) inhibitory peptide derived from duck meat hydrolysate

ABSTRACT In this study, the ACE-inhibitory peptide (<3 kDa) was obtained through ultrafiltration of duck meat enzymatic hydrolysate. The research investigated the effect of processing conditions (heating, pH, NaCl, glucose) and simulated gastrointestinal digestion on the activity of peptide. It was found that contents of NaCl and glucose, heating temperatures (up to 100°C), and heating times (20–120 min) had no significant effect on the activity of peptide. The peptide attained highest activity at pH = 7, while sharply declined at alkaline condition. The activity of peptide significantly increased by 9.08% than before in vitro digestion. Peptides were cleaved into smaller fragments after pepsin digestion and leading to increased exposure of internal hydrophobic residues. With further treatment of trypsin, more free amino acids were released and surface hydrophobicity was declined. The study showed that the activity of ACE-inhibitory peptide has ideal tolerance for different processing conditions and in vitro gastrointestinal digestion