Why do apples turn brown
Apples are not the only fruits or vegetables that turn brown after being sliced because potatoes, bananas and a few others also exhibit the same color change. The reason why apples and other fruits and vegetables turn brown is because they contain iron in them. What happens is that when the apple is cut, the cells are injured and thus the exposed portions of the cells come in full contact with the outside air. Apples and bananas contain iron in them, so on being sliced; the oxygen in the air oxidizes the iron to form the brown rust which we see on the fruit’s sliced parts. The procedure of the oxidation reaction is regulated by polyphenol oxidase or tyrosinase enzymes found within the fruit. It is actually a natural healing process, similar to the brown scabs we see on our own body a while after we receive a cut. The apple orchards are now grown from seeds of such varieties that produce apples which have a lesser amount of PPO in them, which in turn, reduces the apple’s susceptibility to oxidation when sliced.
Now that the reason why apples turn brown has been answered, it is time to know a few simple ways to prevent or at least reduce the brown color formation in apples. An easy and simple way to prevent apples from turning brown quickly is to emerge the sliced pieces into water immediately, so that it does not come into contact with the oxygen in air. Another simple solution is to pour some lemon juice onto the freshly cut apple before you store it, as that will significantly reduce the rate of enzyme induced rusting. Other additives that have similar retarding effects include pineapple juice and sugar syrup. Another effective way to temporarily eliminate PPO activity is to heat the apple. Do not heat it directly in the flame, but boil the sliced apple for five minutes in water.
An apple that has turned brown due to enzymatic rusting might look different, but by no means is it bad for you. It is perfectly safe to eat brown portions in an apple and it does not taste much different from the white portions of the apple either.