chemistry of caroteniods

3. CAROTENIO
DS

4. What is Carotenoid?
Carotenoids are organic
oil-soluble pigments
found throughout
nature
 Tetraterpenoids

5. History:
 Wachen proposed term “Carotene” for a pigment
crystallized from carrot roots.
 Berzelius named polar yellow pigment
“Xanthophylls”.
 Tswett separated pigments & called them
“Carotenoids”.

6. Occurrence:
Chromoplast of plants, algae,
some fungi and bacteria.
Micro-organisms and animals
Color ranges from “Yellow”
through “Orange” to “Red”

7. Chemical Structure:
Hydrocarbon chains and conjugated backbone.
Tetra-terpenoids produced from 8 isoprene units.
Carotenoids have 40 carbon atoms

8. Color:
 Color ranges from 400-550nm.
 Color basically due to structure.
 Conjugated double bond act as light-
absorbing chromophore.
 Electrons move freely due to
conjugation & require less energy to
change state.
 Color deepen with increasing
conjugation.

9. Biosynthesis of Carotene:

10. 600 types of carotenoids
Two main types
Xanthophyll
Carotene
Classification of Carotenoids:

11. Classification of Carotenoids:
 Acyclic Carotenes: formed by a linear carbon
chain
 Cyclic Carotenes: containing one or two cyclic
structures
 Hydroxytecaronoids: containing at least one
hydroxyl group (xanthophylls)
 Epoxycarotenoids: containing at least an epoxic
group (xanthophylls)

13. Importance of Carotenoids:

14. Physical quencher of singlet and reactive
oxygen specie.
Stop ionization of retina caused by blue light.
Anti-oxidant effect on cholesterol preventing
clogging.
Carotenoids as Antioxidant:

15.  Absorb sun-light energy for plant.
 Xanthophyll is accessory pigment.
 Carotene transmit light energy absorbed from
chlorophyll
 Protect chlorophyll from photo-damage.
Role of Carotenoids in
Photosynthesis: