Carotenoids are organic pigments found in plants and photosynthetic bacteria that are precursors to vitamin A. They are fat-soluble tetraterpenoids produced from 8 isoprene molecules and contain 40 carbon atoms. Common carotenoids include lycopene, alpha-carotene, and beta-carotene. Carotenoids are important antioxidants and are found in foods like carrots, sweet potatoes, tomatoes, and leafy greens. Proper storage, avoidance of light and heat, and protection from oxygen are important to prevent carotenoid degradation.

1. CAROTENOIDS
Prepared By :- Moksha Chib
Roll No :- 13 FET1003

2. Introduction
• Carotenoids are red , yellow & orange organic pigments , found in Chloroplast &
Chromoplast of Plants & Photosynthetic bacteria.
• Carotenoids are the precursor of Vitamin A & are powerful antioxidants that
helps in preventing some form of cancer and heart disease.
• Carotenoids are produced from fats & other basic organic metabolic building
blocks found in Plants & Photosynthetic bacteria.
• Carotenoids cannot be manufactured by species in animal kingdom thus , needs
to be obtained from the diet.
• Most Carotenoids are oil soluble.

3. Chemical Structure
• Carotenoids are tetraterpenoids i.e. they are produced from 8
isoprene molecules & contain 40 carbon atoms.
• All Carotenoids demonstrate a basic structure which consist of a
hydrocarbon chain of varying length & varying types of end groups.
• Carotenoids contains a conjugated backbone composed of isoprene
units, which are usually inverted at the center, imparting
symmetry.

4. Structures of common Carotenoids
Lycopene, Acyclic, Red
‘α Carotene ( Bicyclic, Yellow)
‘β Carotene , Bicyclic, Orange

5. Colour
• Carotenoids gives colour ranging from pale yellow to bright orange
to deep red.
• The C=C interacts with each other , thus forming conjugation
which allows electrons in molecule to move freely. As this activity
increase , the electrons have more room to move and require less
energy to change states. The colour deepens as the conjugated
system is extended.
• At least 7 conjugated dB are needed for a Carotenoid to impart
colour.
• Cyclization causes some impediment , so α & β carotenes
are orange & red orange in colour respectively.

6. Classification of Carotenoids
CAROTENES
• Oxygen free Carotenoids which
contains only carbon &
Hydrogen.
• Readily soluble in petroleum
Ether & hexane.
• Found in carrots, Apricots &
gives bright orange colour.
• E.g Lycopene, β Carotene
XANTHOPHYLLS
• Contains 1 or more O2 atoms
and functions like hydroxy,
epoxy, keto, carboxy and
methoxy groups.
• Dissolve best in Methanol &
Ethanol.
• Generally yellow in colour.
• E.g Lutein, Zeaxanthin

7. Properties
of
carotenoids
Quench
singlet
electron
Lipophilic,
insoluble in
water
Bind to
hydrophobic
surfaces
Easily
isomerizes
& oxidized

8. Food Sources
• Carotenoids in food are mainly found in trans form.
• Major food sources are Carrots, Sweet Potato, Dark leafy greens
especially broccoli & spinach , Tomato, Pumpkin, Palm oil & fruits
like apricot, Papaya & Mango.

9. Food Sources - Green
• They contains hydroxycarotenoids, Epoxycarotenoids &
Hydrocarboncarotenoid.
• Substantial amount of Chlorophyll is present which masks the
orange yellow colour given by the Carotenoids.
• Carotenoids are present in the form of protein – Carotenoid
complex.
• Major Carotenoids found in greens are β & α Carotene.

10. Food Sources – Yellow / Red
• These contains hydrocarbon Carotenoids.
• Apricot, Carrot , Pumpkin are major sources of β & α Carotene.
• Tomato , Watermelon are sources of Lycopene, Phytoenes.
• Carotenoids exists as crystals in these sources.

11. Food Sources – Yellow / Orange
• These contain Hydroxy Carotenoids, Epoxy Carotenoids which are
esterified with straight chain fatty acid esters such as Lauric Acid
& Mystic acid.
• These Carotenoids are present in the form of oil solution.
• Food sources are Mango, Papaya, Peach & Orange.

12. Alpha-Carotene Content of Selected Foods
Food Serving Alpha-Carotene (mg)
Pumpkin, canned 1 cup 11.7
Carrot juice, canned 1 cup (8 fl oz) 10.2
Carrots, cooked 1 cup 5.9
Carrots, raw 1 medium 2.1
Mixed vegetables, frozen,
cooked
1 cup 1.8
Winter squash, baked 1 cup 1.4
Plantains, raw 1 medium 0.8
Collards, frozen, cooked 1 cup 0.2
Tomatoes, raw 1 medium 0.1
Tangerines, raw 1 medium 0.09
Peas, edible-podded, frozen,
cooked
1 cup 0.09
Beta-Carotene Content of Selected Foods
Food Serving Beta-Carotene (mg)
Carrot juice, canned 1 cup (8 fl oz) 22.0
Pumpkin, canned 1 cup 17.0
Spinach, frozen, cooked 1 cup 13.8
Sweet potato, baked 1 medium 13.1
Carrots, cooked 1 cup 13.0
Collards, frozen, cooked 1 cup 11.6
Kale, frozen, cooked 1 cup 11.5
Turnip greens, frozen, cooked 1 cup 10.6
Pumpkin pie 1 piece 7.4
Winter squash, cooked 1 cup 5.7
Carrots, raw 1 medium 5.1
Dandelion greens, cooked 1 cup 4.1
Cantaloupe, raw 1 cup 3.2

13. Stability of Carotenoids
• Carotenoids generally have good heat stability as they can hanlde
high temp & High pressure processing.
• They work best in pH above 3.5.
• They can be degraded by light , Low pH , Oxygen and enzymes.
• Carotenoids can undergo ISOMERISATION & OXIDATION , stimulated
by Light. However, excessive stimulation may result in undesirable
flavors & loss in colour due to formation of Volatile compounds.

14. Factors affecting Carotenoids content
• Maturation & Ripening
• During ripening Chloroplasts are degraded & transformed into Chromoplast
, leading to synthesis of Carotenoids ( Alphonso Mango & Tomato ripening).
• Fruit & Vegetable structure
• Carotenoids are reportedly more concentrated in the peel than
in the pulp of the fruit. E.g. Tomato
• Other Factors
• Exposure to the sun light & elevated temp in creases the Carotenoids
biosynthesis.

15. Effects of Home Processing & Cooking
• Cooking & Blanching
• As a result of heat treatment during cooking , Carotenoids may undergo
oxidative degradation, Structural transformation or stereoisomerisation.
• Heating process results in chromplast disintegration, Carotenoids being
dissolved in cellular lipids thus leading to a colour shift.
• Canning
• Restoring temperature increase the cis isomerisation & reduces the
carotene content due to enhanced oxidation and isomerisation.

16. Effects of Home Processing & Cooking
• Dehydration
• Dehydration results in severe degradation & isomerisation of Carotenoids
specially if the dried vegetables are kept unprotected from light & Air.
• Discoloration of Dried vegetable is promoted by high temperature.

17. Losses incurred during STORAGE
• Storage at 7-20°C for 16-43 days causes a substantial decrease in
total carotenoid content even when fruits are ripened at optimal
temperatures.
• Losses in α, β carotene and lutein increases in carrots as storage
temp increases above 4°C.
• Both sweet pepper and parsley loose over 20% of their total
carotenoid content at cold room storage (7°C) for 9 days.
• Indian Tuber shows irregular behaviour as its Carotenoids content
increases with storage at 4°C & 25-30°C but decreases with 15-
20°C.

19. Preservation
• Adeqaute modified atmospheres (MA) & controlled atmospheres
(CA) i.e with low concentration of O2 are known to maintain
carotenoid content.
• Samples are grown under N2 in the dark in the presence of
carbonate sources like NACO3/NaHCO3 and an antioxidant
(Pyragallol) which would ensure exclusion of oxygen.
• Avoiding high temperature and protection from light retains the
carotenoid content.
• Chloroform, dichloromethane, tert-butylmethyl ether which are
distilled solvents free from impurities are also used.

20. Analysis of Carotenoids
• Analysis of carotenoid can be performed spectrophotometrically
such as identifying β carotene using its specific absorption
coefficient at 450nm or by HPLC.
• Separations are performed on C18/C30 reversed phase HPLC
columns using mixtures of acetonitrile, methanol, chloroform as
mobile phases.
• Detection is performed using diode arrays or mass spectrometric
detection.