Bixin


Bixin is an apocarotenoid found in annatto, a natural food coloring obtained from the seeds of the achiote tree. Annatto seeds contain about 5% pigments, which consist of 70-80% bixin.
Bixin is chemically unstable when isolated and converts via isomerization into trans-bixin, the double-bond isomer.
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.