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apple browning

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apple browning

Postby Freedom » Tue Sep 06, 2005 9:04 am

Hi guys!

you know how when you cut open an apple it goes brown...what is the brown stuff?

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Postby baikuza » Tue Sep 06, 2005 9:31 am

I think the brown colour is caused by the oxydation. something in apple oxydate with the air and become brown
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Postby victor » Tue Sep 06, 2005 9:57 am

To prevent it, just use citric acid that you can get it fron citrus..this can prevent from air oxydation.
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Postby chemistry_freako » Tue Sep 06, 2005 9:58 am

Yes, it's due to oxidation. One example would be the ascorbic acid (Vitamin C) contained in the apple.

U might find this useful:
http://www.geocities.com/perfectapple/brown.html
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Postby Freedom » Tue Sep 06, 2005 10:40 am

Cool.

So, say i wanted to do an investigation into apple browning, can anyone give me an idea of what i should test for?

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Postby biostudent84 » Tue Sep 06, 2005 11:23 am

There are certain enzymes in apples (can't remember their names this early in the morning) that cause the oxidation. They are also in potatoes as well. Uncooked potatoes brown like that when cut, but not if they have been cooked. The heat from cooking them denatures the enzymes, and no oxidation takes place.
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Postby CynMari » Tue Sep 06, 2005 11:32 am

Since the reaction involves a change of color, you could measure color intensity (with a spectrophotometer) to indicate the rate of browning.
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Postby mith » Tue Sep 06, 2005 12:37 pm

Try freezing the apple and see if browning occurs.
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Postby mothorc » Wed Sep 07, 2005 12:56 pm

Hi
The brown color that you saw is cause by the oxidation of phenolic substances. The phenolic substances appear at the wound of plant tissue
and it react with oxygen in the air.
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Postby ankitshah64 » Sun Sep 11, 2005 3:22 pm

Apple contains iron and when the cut apple expose to air, the enzyme called "tyrosinase" helps to oxidize and turn apple in brown (brown colour is response to reaction occured). However, the apple dipped with lemon juice or sulphur dioxide prevents this reaction since they are anti-oxidants.
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Postby hurly » Tue Sep 13, 2005 5:32 pm

When the apple gets oxidized, does it loose it's antioxidants and all the other nutritions that a normal apple has?

It's not like it's dangerous to eat an oxidized aka brown apple, is it...?
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Postby Winter » Tue Sep 13, 2005 7:17 pm

no, i dont think it is dangerous...
if you don't put lemon juice in a fruit salad with apples in it, the apples will turn brown. It's still edible even if its not pretty...

Also, soaking potatoes in water until you cook them will prevent them from becoming brown.
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