Why do apples and potatoes turn brown when you slice them?

All cells contains thousands of enzymes, and each of these enzymes is necessary for the cell. Check out this HowStuffWorks podcast to learn which enzymes cause apples and potatoes to turn brown upon exposure to oxygen.

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Episode Transcript

Speaker 1 (00:00):
Welcome to brain Stuff from how Stuff Works dot com
where smart Happens. Hi. I'm Marshall Brain with today's question,
why do apples and potatoes turn brown when you slice them?
And how do you keep them from turning brown? All cells,
whether they're bacteria cells, human cells, or apple cells, contain
thousands of enzymes. These enzymes do all the work necessary

(00:24):
for the cell to live its life. Once you cut
the fruit, you open up some of the cells. One
of the enzymes inside the cell, tyrosinees, now has access
to oxygen in the air, and it does its thing,
turning the fruit brown. This is the same thing that
causes brown spots and apples when you drop them. The
easiest way to prevent the browning is to put the

(00:46):
sliced apples in water so that the enzyme doesn't have
access to oxygen. You can also heat the apples to
the nature the enzyme, or lemon juice also inactivates the enzyme.
In humans, tyrosine is also important because it helps create melanin,
which causes tanning. The lack of tyrosenes in humans leads

(01:07):
to albinism. So in humans, the browning that tyrozenes causes
is actually a good Thing. Do you have any ideas
or suggestions for this podcast? If so, please send me
an email at podcast at how stuff works dot com.
For more on this and thousands of other topics, go
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