Article · Wikipedia archive · Last revised Jul 17, 2026

Bixin

Bixin is an apocarotenoid found in the seeds of the achiote tree 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.

Last revised
Jul 17, 2026
Read time
≈ 1 min
Length
310 w
Citations
5
Source
Wikipedia ↗
Bixin1
Skeletal formula
Skeletal formula source ↗
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
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.027.499
UNII
  • 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+ checkY
    Key: RAFGELQLHMBRHD-IFNPSABLSA-N checkY
  • 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
  • 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
C25H30O4
Molar mass 394.511 g·mol−1
Appearance Orange crystals
Melting point 198 °C (cis-isomer)
217 °C (trans-isomer)
Insoluble
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
source ↗
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

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

Applications

Red seeds of the achiote tree source ↗
Bixin is one of the colorants used in the snack Cheetos. source ↗

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 source ↗

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 source ↗
References

References

  1. Merck Index, 11th Edition, 1320
  2. Bouvier, Florence; Dogbo, Odette; Camara, Bilal (2003). "Biosynthesis of the Food and Cosmetic Plant Pigment Bixin (Annatto)". Science. 300 (5628): 2089–2091. Bibcode:2003Sci...300.2089B. doi:10.1126/science.1085162. ISSN 0036-8075. JSTOR 3834418. PMID 12829782. S2CID 560600.
  3. Executive Summary Bixin, National Toxicology Program
  4. Stringheta, Paulo C.; Silva, Pollyanna I.; Costa, André G.V. (2018). "Annatto/Urucum— Bixa orellana". Exotic Fruits. pp. 23–30. doi:10.1016/B978-0-12-803138-4.00006-X. ISBN 9780128031384.