Integrative metabolomic profiling reveals comparable nutritional quality and diminished sensory qualities in Porphyra yezoensis from January versus April harvest.

Although early-harvested Porphyra yezoensis has greater economic value, its nutritional variation from late-harvests remains unclear. Non-targeted UPLC-MS/MS and targeted LC-MS/MS analyses was used to characterize metabolic and nutritional differences between early (January) and late (April) harvests (n = 6 per group). The late-harvests exhibited significant enrichment (P < 0.05) in amino acid, lipid, organic acid, and carbohydrate metabolic pathways, accompanied by higher levels of crude protein, free amino acids, lipids, polyunsaturated fatty acids, vitamins, and crude fiber. Umami amino acids accounted for more than 64% of total free amino acids, while eicosapentaenoic acid constituted up to 60% of total fatty acids. Notably, ginsenoside Rg3 (0.94-0.97 μg/g) was detected for the first time in P. yezoensis. Although late-harvests exhibited reduced palatability due to higher fiber content and a firmer texture, it contained higher levels of several nutrients while maintaining comparable overall nutritional quality, indicating potential applications in functional foods or nutritional supplements.