The document provides information about synthetic food colors. It discusses approved food color dyes and their classification. It also details the advantages of synthetic food colors compared to natural dyes. However, it notes some adverse effects from heavy metals that may be present in food colors like lead, mercury, and arsenic. The document gives permissible limits for these metals set by regulatory agencies. It includes a schematic diagram of the manufacturing process for azo food colors and provides examples of some commonly used mono azo dyes with their chemical structures and intermediates.

1. TECHNICAL REPORT
ON
SYNTHETIC FOOD COLORS
TEXTILE LABORATORY
APPLIED CHEMISTRY RESEARCH CENTER
Pakistan Council of Scientific and Industrial Research
Laboratories. Complex Karachi.
1

2. TECHNICAL REPORT
ON
SYNTHETIC FOOD COLORS
Compiled by:
________________ ___________
Mrs. Munazza Sohail Mansoor Iqbal
Scientific Officer Scientific Officer
Reviewed and Approved by:
______________________
Muhammad Aleem Ahmed
Principal Scientific Officer
Email: texcenter_2004@live.com
munazza_wahab@hotmail.com
TEXTILE LABORATORY
APPLIED CHEMISTRY RESEARCH CENTER
Pakistan Council of Scientific and Industrial Research
Laboratories. Complex Karachi.
Table of Contents:
2

3. S. No Contents Page Nos
1. Title of Project 1
2. Affiliated personnel and organization 2
3. Table of Contents 3
4. Introduction and uses of Food Colors 4
5. List of Approved food colors with details 5---7
6. Background and Classification 8
7. Advantages and Adverse Effects due to heavy metals 9
in Food colors
8. Permissible Limits of Heavy Metals 10
9. Schematic Diagram for the synthesis of Food colors 11
1 Some Details for the Synthesized product “Acid Red 12
0. 33”
1 Some details for Mono Azo Food Colorants 13
1.
Introduction:
Food colors are known as certified colors. A colorant which may either be obtained
from natural or synthetic route, permissible for use in food, drugs or cosmetics by
FDA. All must satisfy strict regulations as to toxicity.
The Natural color extracts, which were used for centuries for coloring food, have been
extensively replaced by synthetic dyes. These synthetic dyes are colored organic
substances that can be applied in solution or dispersion to the food as substrate, thus
giving it a colored appearance. Usually the dyes have an affinity for food stuff and are
readily absorbed from solution.
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4. The synthetic organic colors are superior to the natural dye extract in tinctorial
power, consistency of strength, range and brilliance of shade, stability, ease of
application and cost effectiveness. Many of synthetic coloring material thus selected
for use in foods however the manner in which it is applied is much important from
health point of view.
A color additive is any dye, pigment or substance which when added or applied to a
food, drug or cosmetic, or to the human body, is capable (alone or through reactions
with other substances) of imparting color. FDA is responsible for regulating all color
additives to ensure that foods containing color additives are safe to eat contain only
approved ingredients and are accurately labeled.
Uses of Food Colors:
Color additives are used in foods for many reasons:
1) To offset color loss due to exposure to light, air, temperature extremes, moisture
and storage conditions;
2) To correct natural variations in color;
3) To enhance colors that occur naturally; and
4) To provide color to colorless and "fun" foods. Without color additives, colas
wouldn't
be brown, margarine wouldn't be yellow and mint ice cream wouldn't be green.
Color additives are now recognized as an important part of practically all processed
foods we eat.
List of dyes which are called certified Food Dyes:
• FD& C Blue No. 1 – Brilliant Blue FCF, E133 (blue shade)
• FD&C Blue No. 2 – Indigo tine, E132 (indigo shade)
• FD&C Green No. 3 – Fast Green FCF, E143 (turquoise shade)
• FD&C Red No. 40 – Allura Red AC, E129 (red shade)
• FD&C Red No. 3 – Erythrosine, E127 (pink shade, commonly used in glacé cherries)
• FD&C Yellow No. 5 – Tartrazine, E102 (yellow shade)
• FD&C Yellow No. 6 – Sunset Yellow FCF, E110(orange shade)
List of Approved Natural and Synthetic colors for Food items by their E-Numbers:
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5. 100–109 Yellows
110–119 Orange
120–129 Reds
100–199
130–139 Blues & Violets
Colors
140–149 Greens
150–159 Browns & Blacks
160–199 Gold and others
Some Mono Azo dyes used in Food with their EN Numbers and Structures: :
E102 :
Tartrazine
E107 : Yellow
2G
E110 : Sunset
Yellow
5

6. E122 :
Azorubine
E123 :
Amaranth
E124 : Ponceau
4R
E129 : Allura
Red
6

7. E151 : Brilliant
Black
E155 : Brown
HT
Background Information for Synthetic Food Colors:
Artificial food colorings were first introduced after World War II when the chemical industry
met with the food industry regarding using chemical-based colors since they were lower in
cost than natural colors and had a longer shelf life. The safety of the colors was determined
primarily from using LD-50 tests, and the amount was then extrapolated to humans. At the
time of approval, behavioral toxicology testing was not required by the Food and Drug
Administration (FDA) and therefore was not done on the artificial food colors.
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8. Classification of Synthetic Food Colors:
Synthetic Food colors have been grouped into following classes.
• Mono azo
• Diazo
• Triazo
• Triarylmethane
• Xanthene
• Quinoline
• Indigoid
Azo Food colors:
In azo group of colors the chromopheric system consists of essentially of the azo group
on association with one or more aromatic system.
N=N
Azo Group
There may be one or more than one azo group are present in color molecule therefore the
mono azo, diazo, triazo, tetra azo or poly azo dyes are being synthesized. Also the position of
azo groups may differentiate their characteristics. The range of the shades covered by the azo
group in food colors is very wide and including Red, Orange, Yellow, blue, Violet, Brown
and Black.
In most of the countries of world the coloration of food is regulated by FDA and government
status. This is usually achieved by the publication of permitted lists and purity specification
for each colorant and sometimes by the limitation of permitted colorant level in certain food
colors.
Advantages of synthetic Food colors:
1. Safe
2. Uniform Quality
3. Readily available in adequate quantity
4. Good Stability
5. High tinctorial power makes them economically advantages
6. good stability in water and alcohol
7. tasteless and odor less
8. Available in several forms
9. Freedom from bacteriological problem
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9. 10. Compatible in all food and beverages
11. Help to hold down the cost of food since the normal appearance of wholesome
colorful tool can be retained or can be restored if color is lost during processing.
12. promote good health by making nutritious food attractive to the consumer.
The Adverse effects of Lead, Mercury, and Arsenic:
Lead:
Lead is associated with lower IQ and it could also responsible for some cavities in teeth. Lead
exposure has been linked to developmental delays, peripheral neuropathy, alters thyroid
hormones and reduces fertility. In elderly adults level over 4 mcg can have neuro behavioral
effects.
Mercury:
Mercury has been implicated in autism, ADHD, learning disabilities, endocrine problems,
allergies, asthma, rheumatoid arthritis, and a host of other disorders.
According to the FDA, "The toxicity of mercury compounds is extensively documented in
scientific literature. It is well-known that mercury compounds are readily absorbed through
unbroken skin as well as through the lungs by inhalation and by intestinal absorption after
ingestion. Mercury is absorbed from topical application and is accumulated in the body,
giving rise to numerous adverse effects.
Arsenic:
Arsenic poisoning has been associated with respiratory, neurological, developmental, and
cardiovascular issues. It has also been associated with cancer. In fact, an increased risk of
skin cancer in humans is associated with chronic exposure to inorganic arsenic in medication,
contaminated water, and the workplace.
Permissible Limits for Some Heavy metal content in Food Colors:
In the US, FDA specification for food, drug and cosmetics colorants are supported by
published methods, many of which are acknowledge as official methods and reported as such
by the association of official analytical chemist. FDA color additive specifications tend to
differ from their European counterparts by placing lower limit on a smaller number of heavy
metals usually including (Lead, Mercury and Arsenic) and by limiting a smaller number of
organic contaminants .Moisture and diluents limit are usually included and minimum pure
color content is required.
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10. So the General limits of heavy metals in ppm regulated by FDA on which bases a dye can be
accepted as certified food color are as follows:
S .No Name of Metal Limit in ppm
1. Lead ≤10
2. Arsenic ≤3
3. Mercury ≤1
4. Cadmium ≤1
5. Chromium ≤50
6. Manganese ≤100
7. Total heavy Metals ≤40
Schematic diagram for the Manufacture of an Azo Food color
Amine
HCl Coupling
NaNO2 Components
Water Alkali
Water
Coupling solution vessel
Diazo
Vessel NaCl
Ice Course Grinder
Water Course Sieve
Pump
Screening Press Fine Grinder
Coupling vessel Wash Tank Fine Sieve
NaCl
Air Standardizing Mixer
Filtrate to effluent Plant
Primary color
stores
Heating and cooling coils
Filter press
Blending Mixer
Isolation vessel
Dryer
Packing
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11. Some Detail about the synthesized product Acid Red 33: C.I No. 17200
• CAS Number:3567-66-6
• Name:2,7-Naphthalenedisulfonicacid, 5-amino-4-hydroxy-3-(2-phenyldiazenyl)-,
sodium salt (1:2)
• Synonyms:
2,7-Naphthalenedisulfonicacid, 5-amino-4-hydroxy-3-(phenylazo)-, disodium salt (9CI);
C.I. Acid Red 33(6CI,7CI); C.I. Acid Red 33, disodium salt (8CI); 11427 Red; 1424 Red;
Acetyl Red B; Acid Fuchsin Fast B; Acid Fuchsine 38013; Acid Fuchsine 90120;
AcidFuchsine D; Acid Red 2A; Acid Red 33; Acid Red B; Amacid Fuchsine 4B;
AzoFuchsine; Azo Grenadine; Azo Magenta G; Azofuchsin; Azofuchsin (biologicalstain);
Brasilan Fuchsine D; C.I. 17200; C.I. Food Red 12; Certicol Red B;Colacid Red 2A;
Cosmetic Red 17000; D & C Red 33; D and C Red No. 33;D&C Red No. 33; D&C Red
No. 33-307002; D&C Red No. 33-38013;D&C Red No. 33-90120; Disodium1-
hydroxy-2-phenylazo-8-aminonaphthalene-3,6-disulfonate; Edicol Supra Red 10B;Edicol
Supra Red 10BS; Eniacid Fuchsine BN; Fabracid Fuchsine S-B; Fast AcidMagenta; Fast
Acid Magenta B; Food Red 12; Hexacol Red 10B; Hexalan Red B;Hispacid Fuchsin B;
Japan Red 227; Japan Red No. 227; Naphthalene Red B;Puricolor Red ARE 33; Red
10B; Red 10B307042; Red 33; Red No. 227; Romexal Red2A
• Molecular Formula: C16H13 N3 O7 S2 . 2 Na
• Molecular Weight:469.42
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12. • Density:g/cm3
• Melting Point: decomposes below the melting point
• Boiling Point:°Cat760mmHg
• Flash Point: °C
Analytical Comparison of the synthesized product with standard Acid Red 33:
S. No Limits for Standard Product Report of Lab Synthesized product
1. Lead not more than 20 ppm Not detected
2. Arsenic not more than 20 ppm 1.1 ppm
3. Mercury not more than 20 ppm Not detected
Some Mono Azo Food Colors with their Numbers and Intermediates:
S.No Color Name C.I No C.I Food EEC No FD & C No Intermediates
No
Naphthionic Acid,
2- Naphthol-6- Sulphonic
acid,
1- Amaranth 16185 Red 9 E123 Red No 2 2- Naphthol-3,6-
diSulphonic acid,
2- Naphthol-6,8-
diSulphonic acid,
2- Naphthol-3,6,8-
diSulphonic acid
2 Allura Red 16035 Red 17 E129 Red No 40 5-Amino-4-
- Methyoxytoulene-2-Sulphonic
acid,
2- Naphthol-6-Sulphonic acid,
6,6-Oxybis (naphthalene-2-
sulphonic acid),
2,2- Di methoxy-5,5-dimethyl-
diazo amino-benzene-4,4- di
sulphonic acid.
1. Sun Set Yellow 15985 Yellow 3 E110 Yellow No 6 Sulphanilic acid,2-
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13. FCF Naphthol-6-Sulphonic acid,
6,6-oxybis(Naphthalene-2-
sulphonic acid),4,4-
Diazoaminodi(benzene
Sulphonic acid),
2-Naphthol-3,6-disulphonic
acid.
2. Tartrazine 19140 Yellow 4 E102 Yellow No 5 Sulphanilic acid,4 Hydrazino
benzene sulphonic acid,3
Carboxy-1-(4-
Sulphophenyl)-5-pyrazone,4,4-
Diazoaminodi (Benzene
Sulphonic acid)
13