Testing the Different Gelatin Conditions
- Label the 18 cups according to their contents. Each gelatin condition should have a #1, a #2, and a #3 cup.
- Plain gelatin: Total of three cups
- Raw [name of fruit]: Total of six cups—three for the fruit with protease and three for the fruit without protease
- Cooked [name of fruit]: Total of six cups—three for the fruit with protease and three for the fruit without protease
- Protease: Total of three cups
- Cut up each of the fruits. Ask for an adults help with this step. Be sure to wash your cutting board and knife after you cut each fruit.
- Cook 1 ½ cups of each type of fruit. Fruit should be either steamed or boiled for 5 minutes. Leave the other 1 ½ cups raw.
- Add approximately ½ cup of fruit (cooked or raw) to each of the plastic cups that are labeled as containing fruit.
- Put 3 teaspoons (tsp.) of meat tenderizer in a small bowl. Add 3 tsp of water and mix until the tenderizer has dissolved. Put 1 tsp. of the meat tenderizer solution in each plastic cup labeled Protease.
- Make the gelatin according to the package instructions. Prepare enough to make 18 cups of gelatin. Add 1 cup of gelatin liquid to each of the plastic cups. Using a spoon, thoroughly stir the contents of each cup. Make sure to use a different spoon for each condition. You will need a total of six spoons.
- Refrigerate all of the cups, noting the time at which you put them inside the refrigerator in your lab notebook.
- Check the consistency of the gelatin in each cup at regular intervals (once or twice an hour) while the gelatin is solidifying. Be consistent with when you check.
- Examine the gelatin carefully and record your observations in your lab notebook. You may want to create a data table (listing each cup you are testing and its conditions) in your lab notebook to record your results and observations over time.
- In which conditions does the gelatin set? In which conditions does the gelatin remain a liquid? Are there any in-between cases? Do your results make sense to you, and do they support your hypothesis?
- What do your results tell you about how the proteases affect how the gelatin solidifies, and how heat affects the proteases?
The fruits listed above contain proteases, which are enzymes. Enzymes help make certain chemical reactions happen. Proteases specifically act like a pair of scissors, helping reactions take place that cut other proteins up. In this activity youll explore whether these protease enzymes are preventing the gelatin from solidifying (by cutting the gelatins collagen proteins into such small pieces that they are no longer able to tangle together and create a semisolid structure). To do this youll inactivate these proteases by using heat.
Procedure • Make the gelatin dessert according to the package instructions. You will want to prepare at least three cups of liquid gelatin. • Add one cup of gelatin liquid to each of the cups with fruit, and add the third cup portion to an empty cup. You should now have three cups with gelatin liquid in them. • Thoroughly stir the contents of each cup. Use a different, clean utensil to stir each cup. • Refrigerate all three cups, noting the time at which you put them inside the refrigerator. • An hour after you put the cups in the refrigerator, check the consistency of the gelatin in each cup. Continue checking their consistency once an hour until the gelatin in the cup without fruit solidifies. (This will probably take about four hours.) In which condition(s) does the gelatin set? In which condition(s) does the gelatin remain a liquid? Are there any in-between cases? • What do your results tell you about how the proteases affect the gelatin solidification process and how heat affects the proteases? • Extra: In this activity you explored fruits that contain proteases, but many fruits do not contain proteases. You could repeat this activity using apples, blueberries, oranges, raspberries and strawberries—all of which do not have proteases. How well does the gelatin solidify when using fruits that do not contain proteases? • Extra: Meat tenderizer contains some of the same proteases that are found in the fruits explored in this activity. Try making a gelatin dessert with meat tenderizer (by dissolving one teaspoon [tsp.] of meat tenderizer in one tsp. of water and adding this to the one cup of gelatin liquid). Can gelatin solidify when it is made with meat tenderizer? If a solution of meat tenderizer is heated, is the enzyme deactivated? • Extra: You used heat in this activity to inactivate the proteases in fruit, but other temperatures and conditions may inactivate the proteases as well. Does freezing the fruit inactivate the proteases? Do other processes, such as drying or canning, inactivate the proteases? Observations and results Did the cup with the raw fruit remain a liquid? Did the cups with the cooked fruit and no fruit added solidify like normal?
Preparation • You may want to have an adult help cut up the fruit and use the stove. • Carefully cut up one cup of the fresh fruit. • Cook one half cup of the cut fruit. Do this by either steaming or boiling the fruit (with about one quarter cup of water) for five minutes. How does the cooked fruit look? • Add the raw fruit to one plastic cup or drinking glass and the cooked fruit to a different plastic cup. If its difficult to tell the difference between the raw and cooked fruit by looking at them, you may want to label the cups (with tape and a permanent marker or pen).
Normally the collagen proteins in gelatin form a tangled mesh that traps water and other ingredients in it, giving the gelatin its semisolid form when it cools. Proteases can cut up the proteins so that the gelatin cannot solidify. There are several different kinds of proteases in the fruits recommended for this activity, and using any of these fresh fruits should result in gelatin that does not solidify well, if at all. Heating the fruit (through boiling or steaming), however, should inactivate the proteases, and the resulting gelatin mixture should solidify like normal (or nearly normal—if the fruit was hot when the gelatin was added, the solidified gelatin may have been slightly less firm than that in the cup without fruit). The proteases bromelain and papain (which come from pineapples and papayas, respectively) are often used in meat tenderizers. There are several other fruit proteases, however, such as actinidin (from kiwi fruit), ficin (figs) and zingibain (ginger).
Introduction Have you ever noticed that if youre making a gelatin dessert, such as JELL-O, its not recommended to use certain fruits, like pineapple? Why is this? These fruits may prevent the gelatin from solidifying. In this activity youll get to determine if certain enzymes in some fruits can keep the gelatin from gelling—and whether theres a way to still include these fruits without ruining your gelatin dessert!
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Which fruits do not allow gelatin to solidify?
Some fruits, like strawberries (on the left), allow gelatin to solidify around them, while others, like pineapple (on the right), do not allow the gelatin to solidify. Pineapples contain special enzymes called proteases. In this science project you will investigate whether the proteases are responsible for the gelatin not solidifying.
What are the benefits of orange juice combined with gelatin?
Eating orange juice gelatine can help introducing new fruits to the diet if the person in not used to. On the other hand, this dessert also provides a good amount of sugar. Orange juice provides a high source of sugar, hence orange juice gelatine has a great amount of this nutrient and has to be eaten in moderation. This dessert or snack can be beneficial while training.
What fruits are bad for 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.
Which fruits break down gelatin?
Read the box: some fruits have naturally occurring enzymes that will break down the gelatin’s structure and prevent it from setting. Avoid fresh pineapple, kiwi, figs, ginger, papaya, guava, and mangoes. Canned fruits are perfectly fine — such as canned pineapple — and cooking the fruit will also break down the enzymes.