From byproduct to taste enhancer: Effective preparation of γ-glutamyl peptides from Morchella esculenta stipes and their mechanism of taste enhancement

Long-term consumption of high-salt diets can lead to an increased risk of cardiovascular diseases. γ-Glutamyl peptides (GGP) display a taste-enhancing effect, which contributes to salt reduction. However, preparation of GGP in a sustainable fashion is challenging. Morchella esculenta stipe is a byproduct abundant in Glu/Gln, serving as a potential precursor of GGP. In this study, Morchella esculenta stipe was employed to prepare GGP by transpeptidation reaction. The reaction conditions were optimized, and their taste-enhancing effects were evaluated by sensory and electronic tongue analyses. Several novel GGP were identified by LC-MS/MS, and their binding modes with CaSR were analyzed by molecular docking. It was found that the optimal conditions were enzymatic hydrolysis for 5 h, transpeptidation time for 2 h, and enzyme of 12 U/g. GGP displayed a significant taste-enhancing effect based on sensory and electronic tongue analyses. Several novel di-, tri-, and oligo-GGPs were found. Molecular docking revealed that GGP can bind to CaSR through hydrogen bonds and hydrophobic interaction to enhance taste perception. Overall, this study highlights the potential of utilizing Morchella esculenta stipes as a sustainable source of γ-glutamyl peptides, which effectively enhance salt and umami taste perception and may contribute to salt reduction without compromising the taste.