Ultrasound intervention timing manipulates the generation of saltiness/umami peptides in agaricus bisporus hydrolysates: Structural modulation and flavor potentiation insights.

This study focused on the ultrasonic timing within multi-step sequential hydrolysis and its impact on flavor profiles of Agaricus bisporus peptide. Results showed that simultaneous ultrasonication with neutral protease increased soluble peptide content by 41.57% and nitrogen recovery rate to 65.39%. We further adopted ultrafiltration to yield a series of peptides below 3 kDa. Second-stage ultrasonication with flavor protease increased β-turn percentage by 9.35% in the peptides and enhanced saltiness and umami tastes. Peptidomics revealed that the second-stage ultrasonic fraction was enriched in short-chain peptides and had higher frequencies of hydrophobic and acidic residues at peptide terminus. We finally constructed a comprehensive database of saltiness/umami peptide candidates, in which short-chain peptides were enriched more hydrophobic amino acids, while long-chain peptides enriched more saltiness/umami fragments such as Asp-Asp, Asp-Glu, Glu-Asp, and Asp-Asp-Asp. Overall, this study provides theoretical and technical support for the controlled production of mushroom-derived flavor ingredients.