Watch it wiggle. If you've ever eaten in a cafeteria or attended a cookout or family reunion, chances are good that your dessert and salad options included some form of Jell-O. Hundreds of recipes use Jell-O to create everything from your simple institutional-style gelatin squares to ornate designs that incorporate varied flavors, fruit and whipped toppings. Jell-O consists of four basic ingredients:
How can one possibly mold Jell-O into so many different shapes? The gelatin in Jell-O is what allows you to get so creative -- but what exactly is gelatin, anyway? Gelatin is just a processed version of a structural protein called collagen that is found in many animals, including humans. Collagen makes up almost one-third of all the protein in the human body. Collagen is a fibrous protein that strengthens the body's connective tissues and allows them to be elastic â€“ 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. You might experience this as stiff joints from less flexible tendons, or wrinkles due to loss of skin elasticity.
Gelatin can come from the collagen in cow or pig bones, hides and connective tissues. Today, the gelatin in Jell-O is most likely to come from pigskin.
Collagen doesn't dissolve in water in its natural form, so it must be modified to make gelatin. Manufacturers grind the body parts and treat them with either a strong acid or a strong base to dissolve the collagen. Then the pre-treated material is boiled. Controls at every step of the process ensure 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, cut and dried in a special chamber. At this point, the dried gelatin -- about 10 percent water -- is ground. If it's going to make Jell-O, it will be ground into a fine powder.
How does this powder become the Jell-O we eat? Head to the next page to find out.
What makes Jell-O wiggle and jiggle?
When you buy a box of Jell-O (or another brand of gelatin) at the grocery store, you get a small packet of the powdered gelatin with sugar or artificial sweetener and artificial flavorings and colors added. At room temperature, the gelatin protein is in the form of a triple helix. This is a fairly ordered structure not unlike that of DNA. With DNA, two chains of nucleotides are twisted together in a spiral pattern resembling a ladder, in 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. These amino acids are mostly glycine, proline and hydroxyproline. Weak bonds hold the helix together. To make a gelatin mold, you add boiling water to the powdered gelatin. You then stir the mixture for about three minutes until the gelatin dissolves completely.
What happens to gelatin when you add boiling water? The energy of the heated water breaks the weak bonds that hold the gelatin strands together. The helical structure unwinds, and you're left with free-floating protein chains. When you add cold water and refrigerate the Jell-O mixture, the chains begin slowly to reform into the tight triple helix structure. As it cools, the mass acts like a sponge, soaking up the water you added. But in some places, there are gaps in the helix, and in others, there is a tangled web of polypeptide chains. The chains form a sort of net, and the net traps water inside pockets between the chains. The protein net is strong enough that the Jell-O holds the shape into which it's molded. But because of the water trapped in the pockets, the Jell-O has the "jiggle" that kids love. Scientists call the form of Jell-O at this stage a colloid, or the substance formed when tiny particles are dispersed within a solution.
See the next page to learn more about uses for gelatin.
Where can you find gelatin?
Gelatin is a common ingredient in foods because it's so versatile. It can be used as a gelling agent (as in Jell-O), as a thickener, to give foods a more pleasing texture and to emulsify (or stabilize) processed foods. It is used to clarify juices, vinegars and even beer. You'll find it in a variety of foods, from yogurt to chewing gum. Special gelatins are made from only certain animals or from fish to meet standards of the Jewish and Muslim religions.
Here are some other foods that commonly contain gelatin:
- gummy bears
- sour cream
- cream cheese
- cake icing and frosting
- soups, sauces and gravies
- canned ham and chicken
- corned beef
- instant drinks
- whipped cream
Gelatin is even used to make the coating for pills that makes them easier to swallow. It's also in lozenges and ointments. Cosmetics may contain a form of gelatin that doesn't gel. You may see it on the label as "hydrolyzed collagen."
Gelatins aren't used just in foods or in health or cosmetic products. Here are some other common uses of gelatin:
- photographic films and papers
- match heads
- glossy printing papers
- playing cards
- simulated human tissue for testing guns and ammunition and for forensic science
- holding the hair of synchronized swimmers in place
To learn more about Jell-O and related topics, head to the links on the next page.
More Great Links
- Chemistry Daily: The Chemistry Encyclopedia. "Gelatin." (Sept. 24, 2011) http://www.chemistrydaily.com/chemistry/Gelatin
- GEA Filtration. "Gelatin Processing Aids." (Sept. 24, 2011) http://www.geafiltration.com/library/gelatin_processing_aid.asp
- Gelatin Manufacturers Institute of America. "Gelatin is pure and natural." (Sept. 25, 2011) http://www.gelatin-gmia.com/html/gelatine.html
- Gelatin Manufacturers Institute of America. "How We Make Gelatin." (Sept. 25, 2011) http://www.gelatin-gmia.com/html/rawmaterials.html
- Goodsell, David. "Collagen: April 2000 Molecule of the Month." Protein Data Bank. (Sept. 26, 2011)http://www.pdb.org/pdb/101/motm.do?momID=4
- Kraft Brands. "The History of the Wiggle." (Sept. 25, 2011) http://w3.kraftbrands.com/Jello/explore/history/
- National Institutes of Health. "Collagen: The Fibrous Proteins of the Matrix." Bookshelf: U.S. National Library of Medicine, National Institutes of Health. (Sept. 24, 2011) http://www.ncbi.nlm.nih.gov/books/NBK21582/
- New Mexico Institute of Mining and Technology. "The Science of Jell-O." (Sept. 24, 2011) http://infohost.nmt.edu/~fuierer/Mate%20101L%20Posters/Jello%2520revised.pdf
- Senese, Fred. "What's Jell-O â„¢ Made of?" General Chemistry Online. Frostburg State University. (Sept. 26, 2011) http://antoine.frostburg.edu/chem/senese/101/consumer/faq/jello-composition.shtml