Species identification of smoked and gravad fish products by sodium dodecylsulphate polyacrylamide gel electrophoresis, urea isoelectric focusing andnative isoelectric focusing: a collaborative study

A collaborative study on the use of sodium dodecylsulphate polyacrylamide g el electrophoresis (SDS-PAGE), urea-isoelectric focusing (urea-IEF) and nat ive isoelectric focusing for the identification of species of smoked salmon ids, gravad salmonids and smoked eels was carried out by eight laboratories . With SDS-PAGE, minor changes took place in the profiles of the processed salmonid species making it impossible or Very difficult to identify closely related species. With urea-IEF, there were fewer changes in the profiles d ue to processing and the system generally had greater species-discriminatin g power for the processed salmonids than SDS-PAGE. The profiles of the eel species as obtained on SDS-PAGE or urea-IEF were not affected by smoking. U rea-IEF had greater species-discriminating power than SDS-PAGE for the eel species. Native IEF was useful in providing supplementary identification on species difficult to identify by SDS-PAGE or by urea-IEF in the case of co ld smoked products. (C) 2000 Elsevier Science Ltd. All rights reserved.