Bixin

Bixin is an apocarotenoid found in annatto, a natural food coloring obtained from the seeds of the achiote tree (Bixa orellana). 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 (β-bixin), the double-bond isomer.

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

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