Integrated peptidomics and in-silico approach for elucidation of the flavour generating peptides in enzymatically hydrolysed shiitake mushroom extracts.

Shiitake mushroom (Lentinula edodes) is the world's second most cultivated edible fungus valued for its delicious taste and unique flavour. Abundant in proteins, nucleotides, and fatty acids, it represents a promising raw material for flavour enhancement and product development. This work adopted B. amyloliquefaciens glutaminase to modify and improve the taste characteristics of shiitake mushroom extracts. The enzymatic treatment significantly enhanced the intensities of umami, saltiness, sweetness, and kokumi tastes, and increased the proportion of potential umami peptides by 43 %. Molecular docking revealed that hydrogen bonds, van der Waals forces, carbon‑hydrogen bonds, and electrostatic attractions stabilized the binding of umami peptides to active residues in the T1R3 receptor. Similarly, Glu297, Ser170, and Arg66 were identified as critical residues for the interaction between γ-glutamyl peptides and the calcium-sensing receptor (CaSR). Two umami peptides (GY-10 and NV-10) and two γ-glutamyl peptides (γ-EE-8 and γ-EV-8) were synthesized for sensory evaluation. Their recognition thresholds in water and in 0.35 % monosodium glutamate solution were determined, along with their capacity to enhance umami, saltiness, and kokumi perceptions. These data provide a reliable method for enriching taste traits of shiitake mushroom hydrolysate by glutaminase treatment and lay the foundation for salt-reduction strategies using flavour peptides.