colourants from flowers
TRANSCRIPT
Colourants From Flowers
Presented byGomtesh DoshiB.pharm(T.Y)
Under GuidanceMr.Pranav parekh
M. Pharm(Biotechnology)
ALARD COLLEGE PHARMACY
Contents
Introduction
Classification
Disadvantages Of Synthetic Colourants
Advantages Of Natural Dyes
Colour Yielding Plants
Simple Methods Of Dye Extraction
How To Screen Natural Dye Yielding Plants By Simple Methods
Introduction
Natural dyes are derived from naturally occurring sources such as plants (e.g.,
indigo and saffron); insects (e.g.,cochineal beetles and lac scale insects);
animals (e.g., some species of mollusks or shellfish); and minerals (e.g.,
ferrous sulfate, ochre, and clay) without any chemical treatment.
Every herb can be used to make dye.The most common herbal parts used for
extracting dyes are seeds, flowers, leaves, berries, stem, bark, roots. Natural
dyes are now-a-days in demand not only in textile industry but in cosmetics,
food, leather and pharmaceutical industry. Natural dyes are biodegradable eco
friendly.
Classification
Dyes Based On Origin
Vegetable
originAnimal origin
Mineral origin
oIndigoid dyes
oAnthraquinone dyes
oAlpha-hydroxy-napthoquinones
oFlavones
oDihydropyrans
oAnthocyananidins
oCarotenoids
Classification of Dyes Based on Chemical Structures
Disadvantages of synthetic colourants
Artificial dyes can be found in more foods than you might expect. It is easy to see brightly colored candies and drinks and know instantly that they contain artificial dyes, but careful reading of ingredient labels reveals artificial dyes in many potentially surprising food items such as cheese, butter, yogurt, condiments, crackers, pastry, pie crust, red grapefruit, prepared entrees, vitamins and even salmon, to name a few.
Some firmly believe that consumption of artificial dyes, particularly in children, causes symptoms such as attention deficit, allergies, asthma, behavioral changes, hyperactivity, gastric upset, migraines, skin manifestations, and sleep disturbances including night terrors, but others say there is no proof of such effects.
Artificial dyes are derived mostly from petroleum and do not provide any taste or nutritional value to foods. Their benefit to manufacturers lies in making foods appear more ripe, fun or appetizing.
Advantages of Natural dyes
In the twenty first century maintaining a safe environmental balance becomes even
more important. The co‐operation of individuals, communities and countries to make
this happen become a global necessity and the following properties are often considered
to be advantages of natural dyes.
They are obtained from renewable resources.
No health hazards, sometimes they act as health cure.
Practically no or mild reactions are involved in there preparation.
No disposal problems
They are unsophisticated and harmonized with nature.
COLOUR YIELDING PLANTS
Tagetes erecta - L.
Synonyms : African Marigold.
Family: Asteraceae or Compositae
Hibiscus rosa Synonym: Chinese hibiscus, China rose, Shoe-Black, Shoe-back-
plant Family – Malvaceae
Natural Dye yielding plant
Senecio hybridus flower
Portulaca oleracea flower
Nerium oleander flowers
Simple Methods of Dye Extraction
Aqueous Method
Alkaline Method
Acidic Method
Alcoholic Method
How to screen natural dye yielding plants by simple methods
Test‐I: Squeeze the plant part preferably flowers and leaves between the
fingers if color is discharged, it may be a good source of natural dye
Test‐II: If the color is retained on the fingers even after washing the hand with
water, it may be a good source of natural dye with probably good wash
fastness.
Test –III: Crush the plant part in pestle‐mortar and smear the crushed plant
paste on filter paper, if the color retains on paper, it may be a good source of
natural dye
Test‐IV: Place this filter paper under table lamp for 3‐4 hours, see if the color
remains the same or fades off, if the color does not fade, it may be a good
source of natural dye with good light fastness properties
Test‐V: Take hot water and put crushed plant part, if it releases color into the
water, it may be a source of natural dye.
Conclusion
Now-a-days, fortunately, there is increasing awareness among people towards natural
products. Due to their non-toxic properties, low pollution and less side effects, natural
dyes are used in day-to-day food products. Although the Indian subcontinent possesses
large plant resources, only little has been exploited so far. More detailed studies and
scientific investigations are needed to assess the real potential and availability of natural
dye-yielding resources and for propagation of species in great demand on commercial
scale. Biotechnological and other modern techniques are required to improve the quality
and quantity of dye production.
Due to lack of availability of precies technical knowledge on the extraction and dyeing
technique, it has not commercially succeeded like synthetic dyes. Also, lo colour value
and longer time make the cost of dyeing with natural dyes considerably higher than with
synthetic dyes
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