Impact of processing on stability of angiotensin I-converting enzyme (ACE) inhibitory peptides obtained from tuna cooking juice

In this study, angiotensin I-converting enzyme (ACE) inhibitory peptides, which had previously been identified in an active gelfiltration fraction from tuna cooking juice, were examined for the stability of their inhibitory properties and composition changes during processing and in the presence of gastrointestinal proteases. Results indicated that ACE inhibitory peptides reserved almost the same composition before and after various temperatures (20–100 °C), levels of pressure (50–300 MPa) and pH (2–10) treatments. ACE inhibitory peptides retained 95–99% activity after simulated digestion. High Performance Liquid Chromatography (HPLC) chromatograph peptide mappings exhibited slight differences before and after temperature (100 °C), pressure (300 MPa) and pH (2, 10) treatments. Our results indicate that tuna cooking juice-derived ACE inhibitory peptides possess some degree resistance to the influence of temperature, pressure, pH treatments, and gastrointestinal proteases.