The term "FD&C color", often seen on ingredients labels, refers
to "Food, Drug, and Cosmetic" colors. These are organic
compounds (as opposed to inorganic pigments such as
titanium dioxide) that
are so intense in color that very tiny amounts can be used to
color something, and thus can be used in concentrations so
minute that they are safe for consumption.
As further described in the section on
β-carotene, organic dyes
owe their colors to "resonance structures" in the molecule,
where charges are free to move in the molecule at frequencies
that fall in the range of visible light.
There are only seven non-natural (artificial) colors certified for
consumption in the United States:
is allowed only in hotdog and sausage casings.
Other FD&C colors are used in drug coatings and cosmetics.
If one of the above colors is used in a food product, it must
be explicitly labeled in the ingredients list,
(e.g. "contains FD&C Blue #1"). If the label does not
name the compound specifically, but simply says something
like "contains artificial color", then you know it does not
contain one of the colors listed above.
A pigment is a solid that has a color. A dye is a liquid that
has a color. FD&C colors are all dyes. To make a solid color
from a dye, the dye is used to color a solid substance. The
result is called a "lake". One common substrate used is
aluminum hydroxide (commonly used as an antacid). A color made
this way might be labeled "Red 40 Aluminum Lake". Lakes are
often used on the outside of candies and pills, so that the
dye does not wash off, or rub off on fingers.
Besides artificial colors, many natural colors are used in foods.
Some of these are:
One of the most widely used colors is caramel, the color
of burnt sugar.
There are many different types of caramel color, each engineered to
serve a particular purpose in food chemistry. They are all based
on the cooking of
starches. Sometimes acids
are used to
break the bonds between sugars to create invert sugars, or to make
sugars from starches, before the sugars are raised to a higher
temperature for carmelization.
The heat is carefully controlled during carmelization to get the
right products from the reaction. Besides acids, alkalies and
salts may be used to further control the process.
Caramel color is a colloid, a mixture in which solid particles
are suspended in water. The particles in colloids have electric
charges that keep the particles from clumping together and settling
out of solution. The charges can be positive or negative.
If a negative coloid is added to a product that has positive
colloidal particles in it, the two will attract one another and
clump up, making the product cloudy.
Caramel color can be made with either positively or negatively
charged particles. This allows manufacturers to use negative
colloidal caramel in acidic soft drinks, and positive in
beers and soy sauces. Beer has positively charged proteins
suspended in it, and soy sauce has a high salt content that
requires the more salt-tolerant positive caramel color.
Caramel color is an emulsifying agent as well as a colorant.
In soft drinks, it helps keep the flavor oils suspended in
In chocolate milk, the muddy color of caramel is darkened by
the addition of
FD&C Red #40
to give what the industry refers to as a "Dutch" chocolate shade.
Blues and yellows are sometimes used to give a more brown color.
Caramel color is added to baked goods, to poultry, to milk to
give an "eggnog" color, to malt vinegars, canned meats, syrups,
and soups, stews, and gravies.