Metabolic and sensory profiling of edible seaweeds: Unraveling the biochemical basis of taste profile complexity.

Seaweeds are rich in bioactive compounds that contribute to their diverse taste profiles and nutritional benefits. Understanding the metabolic basis of their sensory attributes is essential for optimizing their use in food products. This study investigates the taste profiles and metabolic distinctions of four seaweed species (Saccharina japonica, Pyropia yezoensis, Undaria pinnatifida, and Ulva lactuca). Electronic tongue and sensory analysis revealed interspecies differences, with P. yezoensis characterized by pronounced umami and saltiness, U. pinnatifida by sweetness, and S. japonica by astringency, bitterness, and sourness. Metabolomic analysis identified 844 metabolites, uncovering distinct species-specific metabolite profiles. Amino acids, nucleotides, organic acids, and their derivatives emerged as key biomarkers, with P. yezoensis enriched in amino acid metabolism, U. lactuca emphasizing pyrimidine metabolism, and S. japonica favoring purine metabolism. Major taste-active compounds included amino acids (Asp, Glu, Thr, Ala, Cys, His, and Phe), nucleotides (5'-IMP), organic acids (tartaric acid and lactic acid), saccharides (mannitol, glucose, and fructose), and mineral ions (Na, K, and Ca) whose synergistic effects significantly enhanced taste complexity and richness. Notably, P. yezoensis demonstrated the highest synergistic umami equivalent concentration, attributed to the interplay of amino acids and nucleotides. These findings elucidate the biochemical underpinnings of seaweed taste profiles, offering a foundation for targeted improvements in seaweed-based food products by leveraging their unique sensory and biochemical attributes.