The stability t heat and solvent of carotenoids in the Antarctic krill Euphausia superba was examined. When homogenates of the frozen krill were heated at 100°C, little change was noticed up to 1 hour in the content and composition of the carotenoids. After 3 hours of heating, however, the content decreased to less than half and the composition changed into 78% of astaxanthin diester (I) and 21% of astaxanthin monoester (II) with almost complete disappearance of astaxan thin (III) and unidentified carotenoids. As the stability test to solvent, purified I, II, and III were stored in four kinds of solvents, benzent, hexane, acetone, and ethanol, in darkness, at 15°, 0°, and -20°C up to 2 weeks and analyzed for the retained carotenoid. In tbenzene and hexane, I was the most stable without noticeable decomposition. II showed less stable tendencies and III was rather unstable especially in hexane above 0°C. In acetone and ethanol, even I was remarkably decomposed at 15°C. As whole, it was concluded that I was the most stable to heat and solvent.
