Characterization of Selenium Species in Extract from Niboshi (a Processed Japanese Anchovy)

摘要

Fish are selenium rich foodstuffs and a major selenium source for the Japanese population. Niboshiis processed from Japanese anchovy (Engraulis japonicus) and commonly used to prepare soup stock forJapanese dishes. In this study, we characterized selenium species in the Niboshi extract by ultrafiltration,ion-exchange chromatography and mass spectrometry. Selenium species in the Niboshi were more extractableby polar solvents (water and ethanol) than an apolar one (hexane) along with amino acids and proteinousspecies. Selenium in the water-extract from the Niboshi was mostly ascribed to organoselenium compoundswith a molecular mass less than 5 kDa. Although selenoamino acids and selenoproteins and their fragmentswere involved in the extract, a large portion of the selenium species appeared to be low-molecular-mass organoseleniumcompounds other than selenoamino acids and their derivatives. Ion-exchange chromatographicseparations revealed that most of the selenium species in the extract possess anionic and/or amphoteric characteristics.One of these selenium species from the Niboshi extract was detected at m/z 577 for 80Se by massspectrometry subsequent to ion-pair extraction.