Jelly, jam and preserves are all made from fruit mixed with sugar and pectin. The difference between them comes in the form that the fruit takes.
- In jelly, the fruit comes in the form of fruit juice.
- In jam, the fruit comes in the form of fruit pulp or crushed fruit (and is less stiff than jelly as a result).
- In preserves, the fruit comes in the form of chunks in a syrup or a jam.
Pectin is an indigestible carbohydrate (fiber). It is found in the cell walls of most fruit. When heated with sugar in water, it gels, giving jam, jelly and preserves their thickness.
Jell-O is entirely different. It is made from gelatin, which is a protein made from animal skins and bones. For information on gelatin, see this Question of the Day.
Here are some interesting links:
- Facts About Jam, Jelly and Preserves
- How Food Works
- What exactly is Jell-O made from? How does it work?
- How do they make cotton candy?
- How do they make maple syrup?
- How much sugar do they really put in soft drinks?