Apple browning

I'm testing different liquids to see which liquid makes the apple brown faster and then see if the apples are in the liquid for 15 minutes instead of three minutes, time could make a difference
Tatum Long
Grade 5


Part One (apple in the liquid for only 3 minutes)

I think the apple will brown quickest in vinegar because there is acetic acid in the vinegar and that might effect the apples browning. 

I also think the apple juice will make the apple brown the slowest because they are made with the same materials.

Part Two ( apples in the liquid for 15 minutes this time)

I think if they are in the liquid longer they will brown faster 


Why do apples brown?

  • when you cut an apple and expose the inside to oxygen it causes a reacton.
  • the reaction is called enzymatic browning 
  • when apple is exposed to oxygen it starts an enzyme called polyphenol oxidase (PPO)
  • PPO oxidizes something called polyphenols
  • this makes a new chemical that reacts with amino acids 
  • this makes melanins which make it brown
  • different apples different amouts of PPO and polyphenol


Why different liquids make apples brown differently?

  • browning can be prevented by lowering the PH on the surrfaces
  • the lower the PH the more acidic
  • acids react with oxygen so the PPO can no longer oxidize the polyphenols


Ambrosia apples 

  • its biggest feature is its colour, its a pink with patches of yelow.
  • its sweet and low acididy
  • Its also a slow browning apple 
  • they also grow in CANADA


Drink ingredients

orange juice

Orange juice is composted of organic acids, suger, such as citric acid, malic acid, and abcorbic acid.

It has:

Suger 18 g

protein 2 g

sodium 10 mg

carbhohydrate 22g

ingredients: water, concentrated orange juice.


Apple juice

Suger 25 g

protien og

sodium 10 mg

carbohyrate 28 g

Ingredients: water, concentrated apple juice, ascorbic acid (vitaiman C )



Suger 29 g

protien  o.1 g

carbohydrate 31 g 

Ingredients: filterd water, lemon juice from concentrate, suger\glucose-fructose, natural flavour.


Sugers 39 g 

protien o g

cabohydrate 39 g

ingredients: carbonated water, suger\glocose- frutose, carmle colour, phosphoric acid, natural flavour, caffeine.


Part One (3 minutes in the liquid)

My controlled variables:

  • all the drinks are at the same temperatures (4 degrees Celsius)
  • the same type of apples which was ambrosia apples
  • same amount of liquid, I used 125 ml of each liquid
  • they were all in the liquid at the same amount of time, they were each in the liquid at the same time for 3 minutes
  • I made my observations at the same times, which were; 3 minutes, 6 minutes 30 minutes, 60 minutes ( 1 hour), 2 hours, 3 hours, 4 hours, the next day.
  • the cups were the same size
  • the time of the day was the same (4:40)
  • the house tempeture was 21 degrees Celsius on both days

My changing variables:

  • we used seven different liquids: vinegar, lemonade, apple juice, pure lemon juice, coke, orange juice, tap water.


part two (15 minutes in the liquids)

  • the experiment is the same as above  but instead we put the apples in for 15 minutes not three.






  1. step one, first go and get these items: white vinegar, lemonade, apple juice, orange juice, lemon juice, coke, tap water. also apples (ambrosia) plastic cups, you will also need a long big tray, and tongs.
  2. Put all liquids (and apples and lemons) in your fridge, at least overnight. 
  3. set up seven cups and label them with each liquids name.
  4. next, add 125 ml of liquid in the cups that have the label of that liquid, and rinse the measuring cups in between each cup.
  5. Then, cut the apple slices as close as the same size each.
  6. get a timer set up for 3 minutes but don't start it YET. 
  7. next put 1 apple slice in each cup, when you put all apple slices in the different cups start the timer as soon as you can.
  8. After 3 minutes take the apples out of the cups and put them on the tray beside the cup it came out of. 
  9. Immediately start a new timer. Then take observatons at 3 minutes, 6 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, and 4 hours.
  10. Then repeat steps one through nine and compare the results.
  11. For the 3rd time you do the experiment repeat all the steps but, in step six don't leave them in the liquids for 3 minutes this time leave them in the liquid for 15 minutes.


The day the experiment happened: February 7th, 2021

Time the experiment started: 4:40

Experiment #1 (in the liquid for 3 minutes) drink tempature 4o C. house tempature 20o C.

liquids 3 min 6 min 30 min 1 hour 2 hours 3 hours 4 hours
water not alot of change the same some browning nothing is happening  browning in the core the same barely anything is happening
lemon juice not that brown the same  nothing   not really any browning nothing happening not that brown not much browning
lemonade not much change the same pretty white little browning little bit more brown its starting to get brown in core the same little bit of browning
coke brown (maybe from the dye) the same coke is browning at core not really any change its browning in core still brown  its pretty brown in the center
vinegar white the same some browning at core no change  its browning at the core the most brown has a good amount of browning in core
orange juice little brown the same orage juice is browning at core nothing  starting to pretty brown in core the same starting to get pretty brown in core
apple juice not much change the same little bit of browning at core the same as before a little browning in the core the same starting to get a more brown in the center

The day the experiment happend: febuary 11th

Time the experiment started: 4:40

Experiment #2 (in liquid for 3 minutes) drink tempetures 4oC, house tempeture 21oC

Liquids 3 min 6 mins 30 mins 1 hour 2 hours 3 hours 4 hours
water nothing is happening nothing same as before the same kinda brown no change starting to get brownl lttle brown
lemon juice nope nothing nothing its the same as before not anything white  the same as white as it was hen i cut it not brown at all
lemonade nothing the same nothing happening looking brown looking kinda brown is getting little brown in core the same kinda brown
coke its brown only because of the dye the same  the same little brown browning a little is getting pretty brown getting brown
vinegar nothing not browning yet starting to brown at core its getting brown brown in core is really brown vinager is brown at core
orange juice nothing  nothing  the same no change nothing little brown same as before
apple juice nothing not browning the same not really anything happening no change getting brown in core kinda brown

The day the experiment happend: febuary 11th

Time the experiment started: 4:40

Experiment #3 (in liquid for 15 minutes) drink tempetures 4oC house tempeture around 22oC


3 mins 6 mins 30 mins 1 hour 2 hour 3 hour 4 hour
water nothing the same looks the same little bit brown look the same as last hour not much difference not that brown
lemon juice nothing no change no dfferents  white the same no change  really white
lemonade nothing  nothing nothing I can see nothing much the same no change not much browning
coke not any browning yet no change  nope no change little browning getting little bit brown the same just a little brown
vinegar nothing is happening no change starting to brown a little in core starting to get brown some browning in core the same as before just a little brown
orange juice nothing that I can see the same nothing nothing  no change little bit of browning not that brown just a little
apple juice not anything the same as before the same the same little brown no change little browning






The lemon juice browned the slowest because of the low PH. There is low PH in the lemon juice and vinegar, because when the enzyme in the apple is exposed to oxygen  it creates a reaction and turns the apples flesh brown, but when its in a low PH liquid (like vinegar and lemon juice) the enzyme can't start the reaction that turns the apple brown.

The coke was a little brown but it might have been from the dye. The coke was brown when we took it out so I'm guessing it was from the cokes dye, in the end coke was second place, right after vinegar

The vinegar browned the fastest in all three times I did the experiment which was unexpected because the vinegar had low PH. The vinegar could of had  a different result, but our vinegar was old so I think that might have done something to the results

The rest of the liquids started to brown around 2 hours and 3 hours after the vinegar did. Every apple that was browning was starting in core.



In conclusion, the lemon juice makes the apple brown slower and the vinegar makes the apple brown faster, all the other liquids were in between lemon juice and vinegar so some of the liquids could be usd to stop browning but would eventually start to brown after 2 to 3 hours so lemon jucie is the best because it didn't brown at all.


To stop apples from browning in school lunches you can put lemon juice on the apples so they are fresh for lunch.

Sources Of Error

One of my sources of errrors was I couldn't get all the apple slices exactly the same sizes.

Another source of error was the humidity was different the second time I did the experiment

We used a measuring cup but they all weren't exactly the same.


Thanks to my mom for helping me do this project and supporting me!

Thanks to my dad who gave me ideas for my project.