Studies on Optical Isomerism of Astaxanthin in Natural Food Colors and Principal Pigment in Phaffia Color

Chemical forms of astaxanthin in natural food colors were investigated. First, the principal pigment of phaffia color was elucidated by HPLC and LC/APCI-MS. It was revealed to be unesterified astaxanthin, as described in the list of existing food additives. Then, optical isomerism of astaxanthin in three natural food colors that contain astaxanthin in the structures of the principal pigments was studied by HPLC with a chiral column. In phaffia color, saponified haematococcus algae color, and saponified krill color, astaxanthin was present as the (3R, 3′R), (3S, 3′S), and (3R, 3′R) forms, respectively.