Biological conversion of red garlic (Allium sativum L) protein to bioactive peptides: ACE- DPP-IV inhibitory, and Techno-functional features

• Enzymolysis time impacted the amino acid content, functional and biological properties. • The techno-functional features significantly declined near the isoelectric point. • ACE- and DPP-IV inhibitory peptides were obtained from red-garlic protein (RGP). • Extensive enzymolysis (over 90 min) emulsifier capacities and TBARS value. • RGPHs could be known as natural preservative, stabilizer, antihypertensive and antidiabetic. This study explores the impact of enzymolysis on the free amino acid content, techno-functional properties, free-radical scavenging, ACE, DPP-IV inhibition, iron-ion chelation and TBARS production in O/W emulsion stabilized with red garlic protein (RGP) and hydrolysates (RGPHs). The research reveals that enzymolysis time and pH significantly influence the amino acid content (antioxidant, hydrophobic, and essential ones), functional and biological quality of RGP/RGPHs. The study demonstrates that enzymolysis positively correlates with solubility (up to 90%), health-promoting and antioxidant characteristics like DPPH (74.2%), ABTS (81.3%), OH (63.4%), Reducing power (1.1 Abs 700 ), NO (59.5%), TAA (1.4 Abs 695 ), ACE (71.9%), DPP-IV (51.5%) inhibitory, Fe 2+ chelating (46.8%) activity, and leading to reduced water/oil holding capacities, TBARS (from 0.61 to 0.38) value and lipid oxidation. However, extensive enzymatic hydrolysis (over 90 min) reduced emulsion and foaming abilities. On the other hand, the techno-functional properties of RGP and RGPHs exhibited a significant decline near the isoelectric point. This enhancement suggests that RGP could be used as a natural antioxidant with potential health benefits (antihypertensive and antidiabetic) in food and pharmaceutical formulations.