2. WHAT ARE PIGMENTS?
• Pigments are called colorants.
• Pigment generally occurs in living organisms such as plant and
animals.
• Pigments are water-and oil-insoluble natural and synthetic products
that impart color to materials.
4. METHOD OF EXTACTION AND ISOLATION
• Anthocyanin extraction can be carried out using two different solvents:
HCl and Citric Acid.
• CHEMICAL REQUIRED- Methanol or Ethanol, HCl, Citric Acid, Distilled
Water.
• PLANT MATERIAL- Hibiscus rosa sinensis flowers were collected and
they were kept in cold and dark storage until processed. Petals of
flowers chosen were cut into small pieces and into methanol, keeping
them overnight.
5. EXTRACTION USING HCl
• The flower material (4 gm) is dipped in 0.1% HCl (v/v) in methanol or ethanol(10ml)
for 2 to 3 hours at room temperature in darkness without heating or stirring.
• The mixture was filtered on a Buchner funnel.
• The remaining solid was washed with 0.1% HCl in methanol until the clear solution is
obtained.
• The combined filtrates are dried using a rotary evaporator at 550
C.
6. EXTRACTION USING CITRIC ACID
• The flower material (4 gram ) is dipped in 4.0% citric acid (w/v) in methanol
or ethanol (10ml) for 2 to 3 hours at room temperature in darkness without
heating or stirring.
• The mixture was filtered on a Buchner funnel.
• The remaining solid was washed with 4.0% citric acid in methanol until the
clear solution is obtained.
• The combined filtrates are dried using a rotary evaporator at 550
C.
SOLVENT EXTRACTION METHOD USING CITRIC ACID OVER HCl IS
MORE RECOMMENDED AS IT GIVES LARGER AMOUNT OF YIELD .
10. DIFFERENT COLOURS OF
ANTHOCYANIN AT DIFFERENT pH
• Different colouration of
anthocyanin at different pH is
due to the structure
of Anthocyanins having an
Ionic Nature
11. APPLICATION OF ANTHOCYANIN
• Anthocyanin are used as colourants in food colours and dyes.
• Anthocyanins possess antidiabetic, anticancer, anti-inflammatory, antimicrobial,
and anti-obesity effects, as well as prevention of cardiovascular diseases.
Therefore, anthocyanins extracted from edible plants are potential
pharmaceutical ingredients.
• Anthocyanin are used as indicators.