Gastrointestinal digestion enhances the release of bioactive peptides from yogurt

This study investigated whether simulated gastrointestinal (SGI) digestion enhances the release of bioactive peptides from yogurt and improves their associated bioactivities.

Yogurt was subjected to INFOGEST-based SGI digestion. Bioactivities were evaluated using ACE and DPP-IV inhibition and DPPH radical scavenging assays. Protein degradation was assessed by SDS-PAGE, and peptides were identified by UPLC-LTQ Orbitrap mass spectrometry, followed by in silico peptide screening and molecular docking.

Compared with undigested yogurt, SGI digestion markedly enhanced ACE inhibitory, DPP-IV inhibitory, and antioxidant activities, with IC₅₀: 9.6 µg/mL, 300.3 µg/mL, and 530.7 µg/mL, respectively. SDS-PAGE confirmed extensive protein hydrolysis, accompanied by increased peptide content. Peptidomic analysis identified 129 oligopeptides, predominantly < 1.5 kDa, with 31 prioritized as predicted bioactive candidates. Selected peptides exhibited favorable predicted interactions with ACE, DPP-IV, Keap1, and DPPH.

SGI digestion promotes the release of low-molecular-weight peptides with enhanced in vitro bioactivities, providing a peptide-level framework for prioritizing yogurt-derived peptide candidates for future validation. Further experimental validation is needed before functional food, nutraceutical, or therapeutic applications can be proposed.