Bixin is an apocarotenoid found in the seeds of the achiote tree (Bixa orellana)[2] from which it derives its name.

It is commonly extracted from the seeds to form annatto, a natural food coloring, containing about 5% pigments, of which 70–80% are bixin.

It isomerizes into trans-bixin (β-bixin), the double-bond isomer.

[1] Bixin is soluble in fats and alcohols but insoluble in water.

Upon exposure to alkali, the methyl ester is hydrolyzed to produce the dicarboxylic acid norbixin, a water-soluble derivative.