ABSTRACT
Astaxanthin is a fat-soluble xanthophyll, an oxygenated derivative of carotenoids (C40H52O4, FW 596.8 Da). It is closely related to carotenoids such as β-carotene, zeaxanthin, and lutein. Like other carotenoids, the astaxanthin molecule consists of a long chain of carbon atoms held together by conjugated double bonds, the chromophore. Thus, carotenoids absorb light resulting in colorful compounds of different shades of yellow, orange, and red. Two ionone rings, one at each end of the astaxanthin chromophore, modify its optical and chemical characteristics. Also, the molecular environment of astaxanthin (e.g., carotenoproteins in lobster carapace) affect the optical characteristics of the chromophore [1].
