CHROMATOGRAPHIC ANALYSIS OF SYNTHESIZED ASTAXANTHIN: A HANDY TOOL FOR THE ECOLOGIST AND THE FORENSIC CHEMIST?

Abstract Detection of canthaxanthin or of an astaxanthin stereoisomer composition deviating from that in wild salmonids seems to be a reliable method of distinguishing farmed from wild salmonids. This is especially true when a high amount of the (3R, 3'S) stereoisomer of astaxanthin is present. A 1:2:1 distribution of (3S,3'S), (3R,3'S), and (3R,3'S) isomers (“racemic astaxanthin”) is not a fundamental property of the astaxanthin synthesized for fish feeds; virtually any ratio of the astaxanthin stereoisomers may be manufactured by modern techniques. The stereoisomer com-position of astaxanthin from decapod wastes often resembles that of racemic astaxanthin. It is argued that no known chromatographical method today is in itself able to detect any synthesized carotenoid per se. This is important in view of the trend to include untraditional astaxanthin sources in fish feeds, which may eventually make the stereoisomeric ratio most frequently found in farmed salmonids today more differentiated in the future....