Why do canned pineapple and Jell-O set but fresh pineapple and Jell-O fail to set?
Fresh pineapple contains a lot of proteolytic enzymes (they break down proteins). Jello “sets” or polymerizes when small peptide chains (the gelatin in jello is what polymerizes and gelatin is made up of amino acids) become organized. If there is a high concentration of proteolytic enzymes, it will break down any peptide chains and the Jello won’t set. Canned pineapple has been processed and does not contain nearly enough proteolytic enzymes.
