How Does Gelatin Work?

Gelatin makes Jell-O wiggle and provides texture to all sorts of products, but what is it made of? Learn what's happening on a molecular level when you use gelatin in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:02):
Welcome to brain Stuff. From how stuff Works, Hey, brain Stuff,
I'm morn vogel bomb. And if you've ever eaten in
a cafeteria or attended a cookout or family reunion in
the United States, chances are good that you're dessert or
salad options included some form of flavored gelatine, perhaps from
the brand name Jello. Hundreds of recipes use flavored gelatine

(00:23):
to create everything from your simple institutional style squares to
rinate designs that incorporate varied flavors, fruit and whipped toppings.
Jello and similar mixes consist of five basic ingredients gelatine, water,
sugar or artificial sweetener, flavorings, and food coloring. The gelatine
is what allows you to mold the stuff into whatever

(00:45):
shape you like, solid room temperature, but melt in your mouth.
But let's break down why gelatine behaves that way. Gelatine
is a processed version of a structural protein called collagen
that occurs in many animals bodies, including humans, called and
makes up almost one third of all the protein in
the human body. It's a fibrous protein that strengthens the

(01:05):
body's connective tissue and allows them to be elastic, that is,
to stretch without breaking. As you get older, your body
makes less collagen, and individual collagen fibers become increasingly cross
linked with each other. One might experience this as stiff
joints due to less flexible tendons, or wrinkles due to
the loss of skin elasticity. Gelatin can also be made

(01:26):
from the collagen in the bones, hides, and connective tissues
of cows or pigs. Today, the gelatin and jello is
most likely to come from pig skin. Collagen does not
dissolve in water in its natural forms, so it must
be modified to make gelatin. Manufacturers grind the animal parts
and treat them with either a strong acid or a
strong base to dissolve the collagen. Then the pre treated

(01:48):
material is boiled. Controls every step of the process and
sure purity and safety. The materials are washed and filtered repeatedly.
During this process, the large collagen protein ends up being
partially broken down. The resulting product is a gelatin solution.
That solution is chilled into a jelly like material, then
cut and dried in a special chamber. At this point,

(02:08):
the dried gelatin, about ten percent water, is ground. If
it's going to make a flavor gelatine product like jello.
You'll be ground into a fine powder. When you buy
a box of whatever brand of flavored gelatine at the
grocery store, you get a small packet of the powdered
gelatin with a sweetener, flavorings, and colors added at room temperature.
The gelatin protein is in the form of a triple helix,

(02:30):
and this is a fairly ordered structure, not entirely unlike
that of DNA. With DNA, two chains of nucleotides are
twisted together in a spiral pattern, resembling a ladder. It's
a design known as a double helix. In the gelatin protein,
three separate chains of amino acids called polypeptide chains have
lined up and twisted around each other. So to make

(02:51):
this dried gelatin able to fill out and take the
shape of a mold, you first add boiling water to
the powdered gelatin. You then stir the mixture for about
three minute until the gelatine dissolves completely. But what happens
to gelatine when you add that boiling water. The energy
of the heated water breaks the weak bonds that hold
the gelatine strands together, their helical structure unwinds and you're

(03:12):
left with free floating protein chains. Next, you add cold
water and refrigerate the gelatine mixture, which makes the chains
begin to slowly reform into their tight triple helix structures.
As it cools, the mass acts like a sponge, soaking
up the water that you added, But in some places
there are gaps in the helix, and in others there's
a tangled web of these polypeptide chains. The chains form

(03:36):
a sort of net, and the net traps water inside
pockets between the chains. This protein net is strong enough
that the gelatine will hold the shape into which it's
been molded, but because of the water trapped in the pockets,
the mold has that characteristic jiggle. But gelatine isn't just
for making fun molded salads or desserts. Gelatine is a
common ingredient in foods. Because it's so versatile, it can

(03:59):
also be used as a thicken to give foods a
more pleasing texture, into emulsify or stabilized processed foods like
yogurt or cake frosting. It's used to clarify juices, vinegars,
and even beer. Special gelatins are made from only certain
animals or from fish to meet the standards of folks
who don't eat products made from the mammals that are
usually involved, and vegetarian and vegan substitutes made from extracts

(04:20):
of gooey stuff like seaweed are available to the range
of those products that gelatin can be found in is legion.
Everything from dairy and dairy substitute products like sour cream,
margarine and cream cheese, to sweets like gummy bears and marshmallows,
to process meats like sausage and canned ham, to soup sauces, gravies, jellies,
and even whipped cream. It's the coating for pills that

(04:42):
makes them easier to swallow. It's in some lozenges and ointments,
and cosmetics may contain a form of gelatin that doesn't
gell You might see it on the label as hydrolyzed collagen.
And gelatins aren't just used in foods and health and
cosmetic products. It's also commonly used in the manufacture of
photographic films and papers, uch heads, sand paper, glossy printing papers,

(05:03):
playing cards, and simulated human tissue for testing guns and ammunition,
and for forensic science. It's even sometimes used to hold
down the hair of synchronized swimmers in place. Today's episode
was written by Linda C. Brinson and produced by Tyler Clang.
For more on this and lots of other well jelled topics,

(05:24):
visit our home planet, how stuff works dot com.