Yesterday Kam made another jelly with gran.
This reminded him of a different question he had asked me first time round – I didn’t find the answer, it was in my millions of questions to answer list!
What is jelly made from?
Gelatine is a near clear and tasteless water soluble protein. Gelatine contains a protein called collagen. Collagen is found in all animals. Gelatine comes from animal bones, ligaments and tissues.
When we put the jelly cubes in hot water they dissolve. The bonds that hold the collagen protein chains together get broken down by the hot water. Each chain (a triple-helix ) floats in the bowl until the gelatin cools and new bonds form between the amino acids in the protein.
The flavours and water fill spaces between the chains. They get trapped as the bonds set. This is why a jelly wobbles – water gets trapped between the chains. (If we reheat the jelly the bonds holding the protein chains together liquefy the gelatin.)
Effect of Fruit on Gelatin and Jelly
Sometimes we add fruit to jelly. However, some fresh fruits contain proteolytic enzymes (/protease). These enzymes break or cut down the gelatin molecule into peptides (protein fragments) which are too small to form a firm gel. This means, unless we’re careful we get runny jelly or a jelly that doesn’t set. Examples of fruits which give us a runny jelly are:
- kiwi fruit
- figs and
Cooked or tinned fruits denature and deactivate the protease process. Hurray, we can used tinned or cooked pineapple in jelly!
A Note to You and Me
Thank you for reading this post. We have written another post about jelly. Here is the link: