Identification and comparison of umami-peptides in commercially available dry-cured Spanish mackerels (Scomberomorus niphonius)

Dry-cured Spanish mackerel (DSM; Scomberomorus niphonius) is a popularity worldwide dry-cured marine fish product due to its salty and umami flavor. Umami peptides from eight commercial DSMs were identified and compared, and their molecular mechanisms were evaluated via molecular simulation. The results showed that the sequence of peptides varied in different DSMs, wherein only ten sequences were repeated across multiple samples and the remaining 19 were detected in only one sample. The sensory characteristics of eight repeated peptides were evaluated, and four were found to exhibit umami taste and umami-enhancing effects, including Arg-Asp, Asp-Gly-Val, Asp-Arg, and Asp-Lys. They all had a strong affinity for umami receptors, and several amino acid residues of the receptors were mobilized as binding sites to form hydrogen bonds and hydrophobic bonds in ligand-receptor interactions. These results indicated that DSM was rich in umami and umami-enhancing peptides, but their sequence were different in different DSMs.