What exactly is astaxanthin and why does it make salmon red?
Astaxanthin is the red pigment that gives salmon, shrimp and flamingos their pink-red colour. Chemically it is similar to -carotene (in carrots) and vitamin A. It is part of the group of carotenoids. The chemical structure of astaxanthin is shown below: Astaxanthin is made by several kinds of algae and plankton. These are eaten by many aquatic species including crustaceans, amongst which are shrimps, which store the pigment in their shell, resulting in their pink-red exterior. Crustaceans in turn are eaten by fish (salmon, trout) or birds (flamingo, red ibis). These also store the pigment in their skin and fatty tissue. This is the reason why salmon and other animals are red. Astaxanthin does not undergo bleaching, thus these animals retain their pink coloration. The function of astaxanthin in connection with aquatic animals is not entirely clear. However, it is a potent antioxidant, comparable to vitamin E. It may also offer protection against UV light. Only algae can produce astaxant