Adding fruit to gelatin often means watching the fruit sink to the bottom or finding most, if not all, of the fruit on the bottom of the bowl after the gelatin has set. You want the fruit spread out and suspended throughout the gelatin so that you'll taste fruit in every spoonful. Use the proper preparation methods to suspend the fruit or create a fruit layer in the middle of the bowl.
Fruit and Gelatin Science
Some gelatin box instructions recommend avoiding certain fruits - - mango, kiwi, papaya and pineapple, for example - - that have enzymes, which prevent gelatin from setting, according to Scientific American. Add these fruits after the gelatin has fully set or use them as toppings when the gelatin is served. Thaw frozen fruit before adding it to gelatin and drain juice or syrup from canned fruit; the extra liquid can prevent the gelatin from setting fully. Wash fresh fruit and cut it into smaller pieces before adding the little chunks to the gelatin.
Add When Gelatin Partially Sets
Prepare the gelatin as directed by the package instructions and place the covered bowl in the refrigerator. Allow the fruit to become partially set or lightly thickened. The consistency should resemble light and lumpy pudding. Add the fruit to the gelatin and fold gently with a large spoon to distribute the fruit evenly. Return the covered bowl to the refrigerator and leave it until the gelatin is fully set.
Add a Middle Fruit Layer
After preparing the gelatin according to the package instructions, pour half of the gelatin into a bowl and place the covered bowl in the refrigerator to set. Set aside the remaining prepared gelatin to use later.
Allow the gelatin to set partially or until the surface will hold the fruit. Spread fruit on top of gelatin and cover it with the remainder of the prepared gelatin you set aside earlier. Carefully return the covered bowl to refrigerator and leave it until the gelatin is completely set.
Place the remainder of the gelatin in a separate bowl and place both bowls in the refrigerator to set. Once the gelatin is partially set in both bowls, add the fruit to one bowl and spoon the contents of the second bowl over the fruit.
Gelatin molds are assembled and refrigerated until set and removed from the mold as one piece. To add fruit, prepare the gelatin in a bowl and refrigerate until it is partially set. Add the fruit to the thickened gelatin and spoon the mix into a lightly greased or oiled gelatin mold. Place the mold in the refrigerator until the gelatin is fully set. Follow the directions provided by the mold manufacturer, such as setting the mold in warm water for 15 seconds, to dislodge the gelatin from the mold.