Comparison of LC-MS-based non-volatile metabolites of Korean and Japanese lavers (Pyropia yezoensis)

This study compared the free amino acids composition and non-volatile metabolites of Korean and Japanese dried lavers (Pyropia yezoensis) using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). Total free amino acid content of Korean dried lavers ranged from 3,692.51-5,709.58 mg/100 g mg/100 g, which did not significantly differ from that (3,914.89-4,920.77 mg/100 g) of Japanese dried lavers. However, most individual amino acids exhibited statistically significant differences. Metabolite analysis identified 46 major metabolites in dried lavers, including four amino acids, six mycosporine-like amino acids, nine nucleic acids, 19 lysophospholipids, and eight others. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) clearly distinguished between Korean and Japanese dried lavers. The potential distinguishing metabolites found in dried lavers include acetylcholine, 2,6-piperidinedicarboxylic acid, aplysiapalythine B, shinorine, and lysophosphocholine (LPC 20:5). Porphyra-334 (1,227.65-2,192.52 mg/100 g) did not show significant differences between Japanese and Korean dried lavers, whereas shinorine (117.19-459.08 mg/100 g) was found to be higher in Japanese dried lavers than that in Korean dried lavers. These results are expected to be used as basic information for understanding the metabolites of P. yezoensis dried lavers produced in Korea and Japan.