This is an interesting experiment. Gelatin keepsdesserts like Jello semi-solid. The enzyme thatbreaks down the proteins in gelatin isgelatinase. (Most enzymes are named afterwhat they do and end in “ase.”) When the enzymesbreak down the protein, the jiggly block turnsinto liquid.
As you know, some fruits contain gelatinase. Agood way to find them is to test for yourself.Have an adult help you make a batch of gelatin andpour it into a big, flat container, then cut thesheet into blocks when it solidifies. Or poursmall amounts into lots of small containers, likebottle caps or those cups they put ketchup in atsome fast food restaurants. (If you ask nicely andexplain why you want a dozen or so, they willprobably give them to you.)
Each cup or block will be one sample.Scientists use multiple samples that they treatthe same way. This helps us avoid making decisionsthat would only apply to one sample. For example,say that one cup got a drop of pineapple juice init, even though you were testing apples. Or onewas in a warmer place than another one.
Then use small pieces of fruit. Have an adulthelp you with knife safety. Make sure you keeptrack of which fruit you’re using. Put a smallpiece of the test fruit on a set of test gelatincups or blocks and observe any changes. Use atimer and write down your observations. You maywant to make a table first, with times across thetop and each sample down the side. Numberingeach sample will help. Record things like “nochange” or “top looks wet” or “all liquefied” foreach sample.
Some fruits that you might want to testinclude: papaya, kiwi, mango, guava, oranges,apples, figs, peaches. I put in some fruits thathave gelatinase and some that don’t so that youcan have the fun of finding out for yourself. Youdon’t have to test them all. If you explain whatyou’re doing at a place where you normally buyfruit, they may have some old or damaged fruitthey can give you for free.
After you have found one or more fruits thathave gelatinase, the fun really starts. Brainstormas many questions as you can think of about theenzymes and pick one or two to test. I’ll get youstarted by suggesting some general ideas liketemperature (boiling, freezing, warm, cold),dilution (mixing fruit pulp with different amountsof water), pH (acid like lemon juice or alkalinelike baking soda), and time.
As you come up with fair tests for yourideas, think about how you will show your resultsin a graph.
Be sure to thank everyone who helps you withyour experiment.
Enjoy! Thanks for asking,
I like your project. You could try greenbanana and papaya. Pineapple makes the surface ofmy tongue sore, and I think those 2 fruits alsosometimes make the surface of my tongue sore, too. The type of enzyme you want is a'protease'. You can look it up on Google. Then there's meat tenderizer, which has proteases. I suppose one can still buy that at the grocerystore. One protease enzyme is Papain - Ilooked on the internet and discovered that itcomes from papaya, which is another reason to usepapaya on your gelatin.
Thank you for your curiosity!
A plant enzyme named bromelin will causegelatin to lose its setting properties. The enzymebromelin will break down the protein chains thathelp the gelatin to hold together. Bromelin canalso be found in kiwi, ginger-root, papaya, figs,and guava. To find out that the enzyme bromelinwill disrupt gelatin, I visited the websiteGeneral Chemistry Online in the FAQ section. read her
