Impact of the drying process on the flavor characteristics of two economically important laver species, Pyropia haitanensis and Neopyropia yezoensis.

This study investigated the impact of drying process on the flavor profiles of the economically significant Pyropia haitanensis and Neopyropia yezoensis, aiming to clarify how species differences and drying process influence volatile and non-volatile flavor compounds. Using GC × GC-TOFMS and LC-MS, the volatile metabolites, free amino acids (FAAs), and nucleotides were analyzed. A total of 2774 volatile components, including 76 odor-active compounds (OACs), were identified, with aldehydes, ketones, benzenoids, and pyrazines as dominant contributors. The key volatiles responsible for their unique flavor were 2-nonenal, 2-octenal, heptanal, 2-pentylfuran, and 1-octen-3-one. Fresh P. haitanensis exhibited a superior flavor profile due to higher OACs and umami compounds, while high-temperature drying significantly enhanced the umami and sweet flavor notes in N. yezoensis by increasing aromatic volatiles and umami FAAs. These findings demonstrate that species differences and processing methods significantly influence laver flavor, providing valuable insights for improving product quality.