Why can't you put pineapple chunks in Jello?

JellO packages warn you not to put pineapple chunks into the gelatin. Jello is a protein mesh with trapped pockets of liquid; the bromelin cuts the protein chains and keeps the gelatin from jelling properly.

Why do pineapples produce an enzyme that tenderizes meat? It's a defense mechanism. The sap of the pineapple plant contains much higher concentrations of bromelin and can cause severe pain if eaten.

Dr. Ron Rusay has written a simple experiment to demonstrate protein degradation's role in kitchen chemistry.

Author: Fred Senese senese@antoine.frostburg.edu