Bixin

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.^[3]

Bixin^[1]

Skeletal formula
Names
IUPAC name (2E,4E,6E,8E,10E,12E,14E,16Z,18E)-20-Methoxy-4,8,13,17-tetramethyl-20-oxoicosa-2,4,6,8,10,12,14,16,18-nonaenoic acid
Other names cis-Bixin; α-Bixin; 9-cis-6,6'-Diapo-ψ,ψ-carotenedioic acid, 6-methyl ester
Identifiers
CAS Number	6983-79-5 Y 39937-23-0 (trans) Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:3136
ChEMBL	ChEMBL1172615 N
ChemSpider	4444638 N
ECHA InfoCard	100.027.499
PubChem CID	5281226
UNII	9L7T4VB66G Y 6JH6LEZ7HY (trans) Y
CompTox Dashboard (EPA)	DTXSID1024629
InChI InChI=1S/C25H30O4/c1-20(12-8-14-22(3)16-18-24(26)27)10-6-7-11-21(2)13-9-15-23(4)17-19-25(28)29-5/h6-19H,1-5H3,(H,26,27)/b7-6+,12-8+,13-9+,18-16+,19-17+,20-10+,21-11+,22-14+,23-15+ Y Key: RAFGELQLHMBRHD-IFNPSABLSA-N Y InChI=1/C25H30O4/c1-20(12-8-14-22(3)16-18-24(26)27)10-6-7-11-21(2)13-9-15-23(4)17-19-25(28)29-5/h6-19H,1-5H3,(H,26,27)/b7-6+,12-8+,13-9+,18-16+,19-17+,20-10+,21-11+,22-14+,23-15- Key: RAFGELQLHMBRHD-SLEZCNMEBU
SMILES O=C(O)\C=C\C(=C\C=C\C(=C\C=C\C=C(\C=C\C=C(/C=C/C(=O)OC)C)C)C)C
Properties
Chemical formula	C25H30O4
Molar mass	394.511 g·mol−1
Appearance	Orange crystals
Melting point	198 °C (cis-isomer) 217 °C (trans-isomer)
Solubility in water	Insoluble
Hazards
NFPA 704 (fire diamond)	1 1 0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Applications

Red seeds of the achiote tree

Bixin is one of the colorants used in the snack Cheetos.

Several thousand tons are harvested annually.^[4]

Chemical properties

Bixin is unstable. It isomerizes into trans-bixin (β-bixin), the double-bond isomer.^[1]

Chemical structure of trans-bixin

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.

Chemical structure of norbixin