COLOURS

1. COLOURS
NATURALAND SYNTHETIC
Presented by
AARON FRANCIS

2. INTRODUCTION
• The acceptance of food depends to a large extent
upon it’s attractive colour.
• The characteristic colour raw food is due to the
pigments naturally present in it.
• Sometimes artificial colour is added during the
preparation and processing of foods to make them
more attractve.

3. NATURAL COLOURING MATTER
 The natural colours (pigments) in vegetables and fruits can be classified on the
basis of chemical structure as :
1. Chlorophylls (green)
2. Carotenoids (yellow-orange)
3. Anthocyanins (red,blue, purple)
4. Flavonoids (yellow white)
5. Anthoxanthins (creamy yellow)
6. Tannins (colourless)
7. Quinones (pale yellow-black)
8. Xanthones (yellow)
9. Betalains (red)

4. CHOLOROPHYILS
1. These green coloured, fat-soluble pigments involved in in
photosynthesis are present in many plants especially in leafy
vegetable.
eg: cabbage and lettuce.
2. These are of two types chlorophyll a and chlorophyll b at 3:1 ratio
3. These are related to polyphyrins(an important bio-pigments
including hemoglobin)
4. Chlorophylls deteriorate on storage whatever
processing method is used.

5. CAROTENOIDS
1. is are orange-yellow, fat soluble pigments present in many
vegetables and fruits.
eg: carrot, pumpkin, mango and orange.
2. The first carotene was from carrot and hence therefore was
named ‘Carotenoid’.
3. The most widespread carotenoids are Lutein, Violaxanthin
and Neoxanthin found in green leaves.(carotene and
zeaxanthin occur widely but comparatively less)

6. 4. Some pigments predominate in certain plants like lycopene - Tomato, capsanthin - Red
pepper and bixin – Annato.
5. Carotenoids are extracted from annatto,saffron, paprika,tomato,etc.
Extracts contain beta-carotene precursor of vitamin a

7. ANTHOCYANINS
1. These are red blue and purple colour water soluble compounds
occuring in the cell sap of some fruits and vegetables. Eg:
coloured grapes, red cabbage, cherries, apple and in most
flowers.
2. These are Glycosides which on hydrolysis yield coloured
Glycones called as Anthocyanidins. Anthocyanidins are phenyl
benzopyran derivatives and sugars.
Glucosides Hydrolysis Coloured Glycones.
(Anthocyanins) (Anthocyanidins)
3. The common anthocyanins are Pelargonium, Cyanin,
Delphinidin, Peonidin and Malvidin.

8. 4. At low pH, the colour of anthocyanins is intense red which changes to orange-red and
blue or purple as pH rises.
5 Sulphite and Sulphur dioxide rapidly bleaches the colour of anthocyanins.
 Removal of sulphite by boiling and acidification results in regeneration

9. FLAVONOIDS
1. These are are water soluble, polyphenolic substances similar in
structure to anthocyanins which also occur as glycoside.
2. These include the subgroup Flanones, Flavanols, Flavanones,
Chalcones, Airlines and Biflavanyl .Flavonoids maybe the sole
pigment in vegetables as potato, cauliflower and yellow
skinned onion.
3. The flavonoids most commonly found are Flavanols,
Kaemferol, Quercetin and Myricetin.

10. 4. Flavones and anthoxanthins are responsible for the yellow-white
or creamy-yellow colour of potato and cauliflower.
 Flavanones occur in citrus plants as synthetic sweetners.
5. These are stable to heat it and oxidation than the anthocyanins.
 Flavanoid Rutin forms coloured complexes with iron
discolouring canned foods(Asparagus).

12. ANTHOXANTHINS
1. These are creamy yellow , creamy white and yellow white water
soluble compounds occurring in cells saps of some fruits and
vegetables. Eg: Potato, Cauliflower.
2. These are Glycosides ,on boiling with dilute acetic acid gives 1or 2
molecules of monosaccharide and flavone or flavone derivative.
Glycoside + dil.Acetic acid ( boiling ) Monosaccharide+Flavone/derivative
3. The falavone derivatives : Flavanol, Flavanonal or Isoflavone

13. TANNINS
1. These are colourless or yellow substance which turn brown when
fruits and vegetables containing them eg: brinjal, bottle gourd,
apple are cut and exposed to air.
2. Thus tannins are responsible for enzymatic Browning and also
show the astringency of foods.
3. These are complex mixture of polymeric polyphenols also known
as tannic acid or gallotannic acid and derivatives of flavones.
4. They are divided into two major group:
(a) Condensed Tannins. : eg-Catechins and related compounds
(Gallotannins )
(b) Hydrolysable Tannins : eg - Gallic acid (Ellatannins)

14. QUINONES
1. These large number of pigments found in cell sap of flowering plants, fungi,
bacteria and algae.
2. Derivatives are anthraquinones, naphthoquinones and benzoquinones.
3. These range in colour from pale yellow to almost black.
4. Athraquinone derivatives are largest group of pigments followed by
naphthoquinones and benzoquinones.

15. XANTHONES
1. These are a group of yellow pigments.
2. One well known member is mangiferin which occurs as
glucoside in mangoes.

16. BETALINS
1. This hour are group of red and yellow pigments
found in red beet and to to some extent in cactus
fruits, pokeberries a number of flowers
2. There resemble anthocyanins and flavonoid in
structure but unlike them contain nitrogen.
3. They are stable in the pH 4-6 beta degraded by
thermal processing in canning.

17.  According to Fruit Product Order of India (1955) , the
following colouring matters, weather isolated from
natural source synthesized are permitted to be added to
any article of Food,
1. Cochineal or Carmine
2. Carotene and carotenoids
3. Chlorophyll
4. Lactoflavin
5. Caramel
6. Annatto
7. Ratanjot
8. Saffron
9. Curcumin
 Dehydrated beetpowder,carrot Oil and juices of fruits
which impart pink colour to Ice-cream are as food
additives

18. (B) Synthetic Colours
Only pigments from natural sources were available and used
colouring food till the coming of the first coal tar dye 1857.
• In India no coal tar dye aur a mixture there off except the
following are permitted to be used (F.P.O-1955)
COLOUR COMPANY NAME COLOUR INDEX CHEMICAL CLASS
1.Red Poncean 4R 16255 Azo
Carmosine 14720 Azo
Fast Red 16045 Azo
Amaranth 16185 Azo
Erythorne 45430 Xanthane
2.Yellow Tetrazine 19140 Pyrazolane
Sunset Yellow FCF 15985 Azo
3.Blue Indigo Carmine 73015 Indigoid
Brilliant Blue FCF 42090 Triphenyl Methane
4.Green Fast Green 44090 Triphenyl Methane
Green FCF 42053 Triphenyl Methane

19. • Dyes used in food should not be harmful not containing more than
10ppm of Copper, 20ppm-Cromium, 1ppm-Arsenic and 10ppm of Lead
and should be satisfying government rules.
• Colours are generally available in the form of powdery or ready-to-use
solutions.
• The powder should be made into a paste with little cold water and the
requisite quantity of boiling water is added to the paste with constant
stirring.
Sediments if any are filtered.
• To prevent sedimentation, glycerine is usually added to the solution.
• About 10% glycerine or Isopropyl Alcohol also helps in increasing the
solubility.

20. • Dye solutions can be preserved by addition of 10% Alcohol (v/v) and
25% glycerine for shorter period storage (or) 50% glycerine for
prolonged storage
• Spoilage of solutions can also be prevented by the addition of 0.1% of
Sodium Benzoate.
• Any dye added to food shouldn’t exceed 0.2g/Kg of final product

21. THANK YOU