Jell-O® dessert is eaten regularly in about two thirds of North American homes. One of most popular versions of Jell-O® is blue – a colour which attracts kids but turns off adults. It was so successful that in 1992 it was awarded one of the spoof Nobel prizes in chemistry called the ‘Ig Nobel prize’.
Gelatin is a dessert with a long history. In the late 1800’s a cough syrup manufacturer in New York named a new product made of gelatin and fruit syrup ‘jello.’ In those days, making gelatin was a complex operation involving boiling calves feet for hours, straining, skimming off fat, re-boiling, adding eggshells and whites and re-straining, before the gelatin to set over night.
Jell-O® is what chemists call a colloidal suspension. The gelatin is made up of long chains of protein molecules. When you mix it with hot water the protein molecules break apart and become suspended in the water. However they remain as individual molecules, which come back together again to form long chains as the mixture cools.
In Jell-O® the protein chains go in random directions, forming a structure that traps water molecules within it, so the result is a mixture of a solid and liquid. When Jell-O® is hot, it is a solid suspended in a liquid; when it is cold it is a liquid suspended in a solid.
So next time you eat Jell-O®, remember its colourful history and interesting internal structure.