By Elaine Zhang '21
Jell-O, one of America’s most iconic and well-known desserts, often appears in school cafeterias, cookouts, and even the dinner table. You’ve probably eaten it before. Its texture is distinctive — it’s springy yet melts in the mouth. One key aspect is its ability to absorb the flavor of anything it’s added to.
The main ingredient of Jell-O is gelatin, which is why households commonly refer to many different gelatin-based products as "Jell-O.” Gelatin is flavorless and often used as a thickener in not only sweet foods but also savory foods. It starts out like a liquid when warm but cools into a solid material. When making gravy, a similar phenomenon can be observed.
This may come as a surprise to some, but gelatin is actually made from extracting a fibrous protein known as collagen from animal connective tissue. Collagen’s helical structure is made up of three bonded long polypeptide chains. This structure allows collagen to strengthen tissue and give elasticity. In fact, collagen makes up around 30% of the human body, present in skin, tendons, and ligaments.
Collagen becomes gelatin after being treated with acid and heated. The resulting solution is then cooled and ground up. Most gelatin used today is processed into a fine powder or thin sheets from pigskin. As gelatin is heated up, the bonds holding the collagen structure together break, and the proteins gain energy to move around. When it cools, the proteins begin to bond together again as they lose energy. The new matrix network of the protein bonds traps fluid in between, giving Jell-O its distinctive semi-solid, gel-like texture when set. This process is reversible — when heated up, gelatin becomes liquid again.
Gelatin — and by extension, Jell-O — is useful for all kinds of cooking. However, it is not the only one of its kind. Some other substances such as agar-agar behave similarly despite being chemically different. In any case, Jell-O, despite its humble impression, is an interesting material from a chemical standpoint.
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