Why Some Fruits Won’t Set in Gelatin
Certain fresh fruits just don’t allow gelatin to set such as Pineapple, Kiwi, Mangoes and Figs. What makes these fruits so different from others? They all contain bromelain, which has enzymes capable of digesting proteins. The enzymes in bromelain are inactive once they have been heated to about 158 degrees F (70 degrees Celsius), so while fresh pineapple prevents gelatin from setting, canned pineapple (which is heated during the canning process) won’t ruin the dessert. Alternatively, you can place fresh fruits containing bromelain in the microwave to deactivate the enzymes before placing them in your gelatin to set.