Simultaneous Analysis of Purine and Pyrimidine Compounds Associated with the Freshness and Taste of Marine Foods

A high-performance liquid chromatography-based method following the simultaneous analysis of 11 purine and pyrimidine compounds associated with freshness (K value for fish or Xt ratio for marine invertebrates) and umami taste in marine products was developed. This method, which separated 11 compounds in a 55-min cycle using a gradient of pH 3.8 phosphate buffer, acetonitrile, and water as the mobile phase, showed sufficient reproducibility and quantitative ability. Using this method, increases in the K value of an amberjack (Seriola purpurascens) and the Xt ratio of a squid (Todarodes pacificus) because of post-mortem deterioration were evaluated. Furthermore, high- and low-grade lavers (Porphyra tenera) known for their substantial guanosine 5′-monophosphate (an umami taste component) content, were compared using this method. Moreover, other nucleotide 5′-monophosphates, which are also umami components, from canned crab (the snow crab Chionoecetes opilio) and dried shiitake (Lentinula edodes), which is a mushroom containing a lot of guanosine 5′-monophosphate and was used as positive control for analysis by developed method, were successfully analyzed using this method.