Synthesis of Umami-, Salty-, and Kokumi-Enhancing γ-Glutamyl Peptides from Soy Protein Isolate Hydrolysate and Their Taste Mechanism via In Silico Study

A high-salt diet is detrimental to human health, and applying γ -glutamyl peptides, known for their significant taste-enhancing properties, can offer a promising strategy for reducing salt intake while preserving saltiness. This study employed glutaminase-mediated transpeptidation of soy protein isolate hydrolysate to produce γ -glutamyl peptides, followed by identifying peptide sequences through LC–MS/MS analysis. γ -Glu-Gly-Pro-Phe and γ -Glu-Ala-Phe-Phe were selected for solid-phase synthesis and evaluated for their taste-enhancing effects. The results showed that both peptides could enhance saltiness, umami, and kokumi, with taste enhancement thresholds of 0.76 ± 0.22 and 0.58 ± 0.21 mmol L –1 , 0.43 ± 0.18 and 0.40 ± 0.21 mmol L –1 , and 0.25 ± 0.18 and 0.20 ± 0.21 mmol L –1 . Molecular docking and molecular dynamics simulation confirmed their stable binding with the calcium-sensing receptor (CaSR). Overall, γ -glutamyl peptides derived from soybean protein isolate exhibit taste-enhancing properties, making them potentially effective taste enhancers. Graphical