2006-09-13 11:37:27 · 5 answers · asked by BRITT! 2 in Science & Mathematics ➔ Biology
Bananas contain an enzyme called polyphenol oxidase or tyrosinase. Whenever bananas are cut, bruised or left out for a long period of time, the oxygen present in the air readily reacts with the enzyme found in the bananas. This oxidation reaction is seen as a rusting or browning of the banana's surface.
The reaction can be slowed or prevented by inactivating the enzyme with heat (cooking), reducing the pH on the surface of the fruit (by adding lemon juice or another acid), reducing the amount of available oxygen (by putting cut fruit under water or vacuum packing it), or by adding certain preservative chemicals (like sulfur dioxide).
On the other hand, using cutlery that has some corrosion (as is seen with lower quality steel knives) can increase the rate and amount of the browning by making more iron salts available for the reaction.
Eat your bananas everyday :P
2006-09-13 15:13:48 · answer #1 · answered by Carlos M 2 · 0⤊ 0⤋
because if they turned another color you would not want them, am i right. it is just like any other food if you leave a plant without water it will die. the banana is not on the tree anymore and it is only good for a certain period of time.
2006-09-13 11:49:49 · answer #2 · answered by Brian C 1 · 0⤊ 0⤋
It because of all the chemicals in the air plaese choose me as best answer
2006-09-13 11:46:03 · answer #3 · answered by t(-_-)y 3 · 0⤊ 0⤋
they age just like all fruit
2006-09-13 11:40:20 · answer #4 · answered by droid 4 · 0⤊ 0⤋
they rot
2006-09-13 11:40:45 · answer #5 · answered by Nytsuki 1 · 0⤊ 0⤋