Peptide-associated taste differences and underlying molecular regulation in a red variant of Litopenaeus vannamei

Flavor characteristics strongly influence consumer acceptance and preference for aquatic products, yet the molecular basis underlying flavor variation among shrimp strains remains unclear. This study combined electronic tongue analysis, untargeted metabolomics and transcriptomic analysis to characterize the flavor profile of a red variant of Litopenaeus vannamei. Results revealed enhanced saltiness and richness in the red variant compared to the wild-type strain. Metabolomic analysis identified ten potential flavor peptides, three of which (IKRDF, FAEKI and PLEGK) were confirmed to exhibit saltiness. Molecular docking further suggested potential interactions of the flavor peptides with the salty receptor TRPV1 and the umami receptor T1R1. Integrated omics analyses highlighted glycine, serine and threonine metabolism as a key contributor, with the accumulation of dimethylglycine (DMG) reflecting alterations in one-carbon metabolism and redox-related metabolic processes. Together, these findings provide novel insights into peptide-mediated taste formation and metabolic remodeling in the red variant of L. vannamei.