Why does the cut apple turn brown?

The inner part of the apple after cutting often turns dull brown just a moment after exposure to the air, making the apple no longer look delicious . Is the color change so toxic and how to prevent apples from turning brown?

It is caused by the mechanism of apple and fungal resistance . This mechanism causes cells to be affected, for example when you cut an apple, some enzymes in the cell are exposed to oxygen. At that time, enzymes that react with oxygen create an oxidizing layer that provides protection against external bacteria from entering the apple.

More specifically, an enzyme called polyphenol oxidase (this enzyme is also called tyrosinase) , includes monophenol oxidase and catechol oxidase enzymes , which, when exposed to oxygen, cause phenolic compounds in apple tissue to become ortho substances. -quinon or "o-quinon" . O-quinone is the substance that provides the mechanism to protect apples from bacteria and fungi, because they create a natural antiseptic. O-quinone has no color, but they react with amino acids and oxygen, producing melanin, so we see apples exposed to the air turned brown.

If you want the cut sections of the apple to not turn brown quickly, it's simple, just put them in the refrigerator. This will significantly slow down chemical reactions and oxidation. Of course, you can also limit the exposure of the apple to the air by wrapping apples in sealed bags. Another option is to put the cut apple in the water , which will give the same effect.

If you are not afraid to taste the lemon, you can spray pineapple juice or lemon juice on the face of the apple in contact with the air. This will prevent polyphenol oxidase from reacting with oxygen, due to the acidity of pineapple juice, lemon denaturing brown enzymes. (You can also apply this tip with butter, potatoes .). If you don't like the taste of lemon, a similar method is rubbing the cut side of an apple in salt water, sugar, or some type of syrup .

However, there is a method to prevent the browning of apples from heating the apple to a temperature high enough, denaturing polyphenol oxidase . You can do this by dropping the apple in boiling water and soaking for a few minutes.