Why does co-stewing shiitake mushrooms (Lentinula edodes) and beef synergistically enhance umami? An exploration from the perspective of umami peptides.

This study investigated the synergistic umami effect of co-stewed shiitake mushroom (Lentinula edodes) and beef (SSB), focusing on umami peptides. Results showed that SSB exhibited significantly higher umami intensity than did the separately stewed and mixed preparation (SS-SB), despite no difference in equivalent umami concentration, suggesting that additional taste-active components might be involved. Five umami peptides (EVRWD, TLYDER, GDLSLPHQ, EEWKLS, and LSVY) were identified exclusively in SSB and traced to shiitake mushroom proteins, supporting the synergistic effect of co-stewing. These peptides enhanced umami and saltiness with monosodium glutamate and NaCl, improving the umami perception of SS-SB upon reintroduction. Secondary structure analysis revealed a strong correlation (ρ > 0.7) between α-helix content and umami intensity, whereas random coils were linked with bitterness and saltiness. Molecular dynamics simulations demonstrated stable binding of peptides to the T1R3 receptor via van der Waals forces and hydrogen bonds, with TYR236 and SER164 identified as key residues. Overall, these results provide theoretical support for flavor optimization in stewed meat dishes.