“Nori” (dried laver, Porphyra yezoensis UEDA) samples were stored at 20°C for 10, 25 and 45 days under dry and humid conditions respectively, and variations in the contents of organic acids were studied by GLC and supplementary use of GC-MS.
1) Of the eight acids determined, i.e., pyruvic, lactic, oxalic, malonic, fumaric, succinic, malic, and citric acid, the relatively abundant ones were oxalic, succinic, malic, and citric acid.
2) Oxalic, malic, and succinic acid did not show any notable changes in contents on dry storage, however, on humid storage, the contents of the two former acids descreaed rapidly, in contrast to succinic acid content which increased markedly. The content of citric acid rapidly decreased independent of the storage conditions.
3) Two of several unidentified components presumed to be aromatic acids from their mass spectra. The contents of the two acids decreased slowly under dry conditions but, rapidly decreased under humid conditions, disappearing almost completely after 45 days storage.
4) The contents of total volatile acids increased under both storage conditions; however, the rate of increment was larger under humid than under dry conditions.