Basic and Neutral Compounds in the Cooked Odor from Antarctic Krill

The cooked odor concentrate from precooked krill was obtained by a simultaneous distillation and extraction system. The resulting odor concentrate was separated into basic, carbonyl and carbonyl-free fractions. Each fraction was analyzed by gas chromatography and gas chromatography-mass spectrometry. Fifty seven compounds, including 3 pyridines, 10 pyrazines, 6 thiazoles, 3 dihydro-4H-1,3,5-dithiazines, 11 aldehydes, 10 ketones, 4 alcohols, 6 hydrocarbons and 4 other compounds were identified. Twenty two of these compounds were newly found as the odor components of krill. The low molecular aldehydes, which are known to be a part of the precursors of the secondary formation of the cooked odor, were also investigated by thin layer chromatography. Ethanal, propanal and butanal were newly detected.