October 21, 1999
2 min read
What is Jell-O? How does it turn from a liquid to a solid when it cools?
ZoeAnn Holmes in the department of Nutrition and Food Management at Oregon State University offers a short reply: "Jell-O, a brand name, is in general made by heating gelatin (processed collagen) in water. The large, stringlike protein molecules of the gelatin wiggle around in the hot water solution. As the gelatin mixture begins to cool, the protein strands have less and less energy to wiggle, until eventually they eventually bond together. If everything happens correctly, bonding occurs at points along the strands, forming pockets that trap the surrounding liquid. When the process is done, the collagen forms a three-dimensional structure or matrix, known as a semisolid colloidal gel. It is this matrix that gives Jell-O its structural integrity.
"Processed collagen is removed and purified from cattle hides, the same substance that may make your shoes. The cattle hides are high in collagen and a variety of other substances."
David J. McClements, an assistant professor in the Biopolymers and Colloids Research Laboratory at the University of Massachusetts at Amherst, provides this more extensive overview of dessert science:
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"The principal component responsible for the transition from a liquid to a semisolid gel on cooling is gelatin. Gelatin is a protein derived from collagen, the major component of the connective tissue of animals. Jell-O and other, similar products consist of powdered gelatin mixed with sweeteners, flavorings and coloring agents.
"In its natural state, collagen exists as fibers that contain three polypeptide chains entwined into a helical structure. Collagen is converted to gelatin by heating it in the presence of water. This procedure breaks down the relatively weak (noncovalent) bonds holding the three polypeptides together, as well as some of the stronger, covalent bonds, and produces a solution in which the polypeptides are arranged into a predominantly amorphous structure.
"When the solution of gelatin cools below a certain temperature, the molecules tend to associate with one another in order to regain some of their original helical structure. In this way, junction zones are formed. The junction zones mark a local return of the original form: three polypeptide chains in a helical formation. If there is enough gelatin present, a gel will form. The gel consists of a three-dimensional network of gelatin molecules linked by these junction zones, which is capable of entraining large amounts of water through capillary forces. This gel has solidlike characteristics, although it is really a viscoelastic material.
"Gelatin is a thermoreversible, cold-setting polymer: if the gel is reheated, it will convert back to a liquid because the forces favoring the amorphous state (mainly configurational entropy) outweigh those favoring the aggregated state (mainly hydrogen bonds). For this reason, gelatin cannot be used in 'cook and serve' products such as puddings that are supposed to form gels when heated. These products must incorporate a heat-setting polymer, such as starch."
For those interested in history, we add the following details: flavored gelatin was invented by Peter Cooper, the founder of the Cooper Union for the Advancement of Science and Art, in collaboration with his wife, Sarah. General Foods began marketing flavored gelatin under the trademarked Jell-O name in 1897.
FAQs
"The principal component responsible for the transition from a liquid to a semisolid gel on cooling is gelatin. Gelatin is a protein derived from collagen, the major component of the connective tissue of animals.
How does jello turn from a liquid to a solid? ›
Gelatin is soluble in water, so when we add hot water all the gelatin molecules are dispersed and move around in solution (a liquid). As the water cools to room temperature, the gelatin molecules begin to bond with one another.
What is jello solid or liquid? ›
Jello is considered to be a colloid as two different types of phases are microscopically dispersed with one another in it. In jello, solid gelatin protein is dispersed in the liquid form of water. The behaviour of jello is more like liquid due to large space between particles but in actual it is a colloid.
How does jello become jello? ›
Heating breaks the bonds that hold the collagen together. When the mixture cools, the collagen strands reform into a semi-solid state with water molecules trapped inside. This is what gives jello its characteristic jiggly, gel-like texture.
Why is jelly a solid and a liquid? ›
Jelly is actually a semi rigid structure suspended in a liquid, which we call a “Colloid”. Jelly is usually made of gelatin, which is a protein. And protein, as we all know is a solid at room temperature. The gelatin is a sol (liquid) when hot, and a gel (solid) when cooled.
What makes jello solidify? ›
Gelatin, which is a mixture of collagen proteins, solidifies when you cook it because its proteins form tangled mesh pockets that trap the water and other ingredients. After the gelatin cools, the proteins remained tangled.
What is Jell-O made of? ›
“Gelatin, the primary ingredient in Jell-O, is derived from collagen, a protein found in the connective tissues, bones, and skin of animals," Sabat says. "Historically, gelatin was obtained by boiling the bones and tissues of animals, such as cows or pigs, to extract collagen.
Can you drink liquid Jell-O? ›
Jello juice is fun to make and even more fun to drink. Most kids love jello and the grown-ups can relive their childhood years indulging themselves, or, add alcohol for a grown up version.
Is jello good for you? ›
Jello is not the healthiest food option, but eating it in moderation likely won't hurt you. Even though it contains artificial ingredients and has very little nutritional value, many people still eat jello because they enjoy its flavor, consistency, and convenience.
Does jello turn back into liquid? ›
Once gelatin has set it can be melted again and used multiple times. Gelatin has a fairly low melting point and will become liquid if left in a warm environment. Small amounts of gelatin can be melted in a container placed in warm tap water. Larger amounts can be re-heated over a pot of boiling water.
Why Do They Give Hospital Patients Jell-O? Considering how easily digested Jell-O is because of it's smooth, liquid characteristics, patients in hospitals are given the nutrient dense protein for more reasons than just taste and digestion. It also proves to be a good source of calories because of the sugar content.
Does Jell-O have horse bone marrow in it? ›
Urban legends claim that gelatin comes from horse or cow hooves, though that's not the case. The collagen in gelatin does come from boiling the bones and hides of animals processed for their meat (usually cows and pigs).
Why is Jell-O no longer popular? ›
Jell-O's decline
After all, it's commonly associated with patients eating it in hospitals or disgraced comedian Bill Cosby, who was the face of the brand for 30 years. And, Jell-O molds and now-defunct flavors like Italian salad and mixed vegetables are in recipe books for “nauseating” foods.
Is peanut butter a solid or a liquid? ›
By the scientific definition, peanut butter is indeed a liquid.
Is ketchup a liquid? ›
Ketchup sometimes acts like a liquid (it can flow) but sometimes it acts more like a solid (it keeps its shape to some extent). The thickness of most liquids remains the same even if a force is applied to them. But other liquids can get runnier or thicker, depending on how much force is applied.
Is honey a solid or liquid? ›
Honey is typically in a liquid form when you purchase it, but all honey eventually returns to its natural, crystallized state. During crystallization, some of the molecules in honey escape from the liquid substance and form crystals that multiply rapidly, causing the honey to change into a solid form.
How long does it take for jello to become solid? ›
Generally speaking, most jello sets in 2-4 hours. Unless you make an extra-large jello dessert, 4 hours will be enough for gelatin to harden.
What is the chemistry behind jello? ›
When collagen is heated in water, the triple helix unwinds and the chains separate, becoming random coils that dissolve in water: That's gelatin. As the gelatin cools, the molecules try to regain the original helical structure and eventually bond together as they lose energy.
