Fruits That Ruin Jell-O and Other Gelatin Desserts

Jell-O, Fruits, and Enzymes

Pineapple is the main fruit known to ruin gelatin, but other fruits also prevent gelling.
Pineapple is the main fruit known to ruin gelatin, but other fruits also prevent gelling.

laymul, Getty Images

If you add certain fruits to Jell-O or other gelatin desserts, the gelatin won't set up. Here's a look at which fruits have this effect and what happens that causes them to ruin Jell-O.

Key Takeaways: Fruits That Ruin Gelatin

  • Some fresh fruits prevent Jell-O and other types of gelatin from gelling.
  • These are fruits that contain high levels of proteases. Proteases are enzymes that break chemical bonds in proteins, such as collagen in gelatin.
  • Pineapple, kiwi, papaya, mango, and guava are examples of fruits that cause a problem.
  • Heat inactivates proteases, so cooking fruit before adding it to gelatin prevents any issue. Canned fruit has been heated, so it is also acceptable for use in gelatin desserts.

Fruits That Ruin Jell-O

The fruits that ruin Jell-O contain enyzmes called proteases which break the chemical bonds that try to form between chains of protein as Jell-O or other gelatin tries to gel.

  • pineapple - bromelain
  • kiwi - actinidin
  • figs - ficain
  • papaya - papain
  • pawpaw - papain
  • mango
  • guava
  • ginger root

Only Fresh Fruit Causes a Problem

You may have had Jell-O that contained pineapple or another of the fruits on the list. This is because the enzymes in the fruit only disrupt the gelling process if the fruits are fresh or frozen. If the fruit is heated (e.g., canning or cooking) then the enzymes are permanently inactivated, making the fruit perfectly fine for making Jell-O.

Jell-O's versatility enabled it to be used in a wide variety of old fashioned recipes you won't believe people actually ate.