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Science Fact: Why do apples turn brown when cut? What happens if a cut apple is left out for a long time? It seems like. That its “face” has changed and turned into an ugly brown color. Due to which the appetite of the people decreases. Then why does the apple turn brown when it is cut open?
Some people think Apples turn brown when exposed to air? Not Correct Reason! That the iron ions present in apples get oxidized to ferrous iron ions by O2 in the air. So the apples will turn yellow after peeling.
Actually, it is not so. According to experiments, the “yellow-green” in the pale yellow-green sap is due to cytochromes. Not because of Fe 2+ plasma. The brown substance of the apple rind is a color reaction to phenolic compounds. Phenolic compounds (especially polyphenols) are easily oxidized to quinones, and quinones have colors. For example, o-benzoquinone is red. P-benzoquinone is yellow, tannins also contain phenolic hydroxyl groups, and turns black after oxidation. With the participation of enzymes, the rate of oxidation of phenol to quinone is accelerated. For example, catechol (catechol) can be quickly oxidized by oxygen to o-quinone under the catalysis of polyphenol oxidase.
Why do apples turn brown when cut?
The cut surface of the apple turns brown. Because many phenolic compounds in apple cells are oxidized to produce quinone compounds. Quinone is slightly soluble in water to brown the cut surface of an apple. Apples, pears, and some vegetables (such as potatoes, eggplant, etc.) not only appear brown after being peeled or bruised. It is also a result of the action of phenoloxidase.
How to Keep Apples from Browning?
Apples turn brown when cut, prevent apples from turning brown, this is a very difficult task, so some ways to prevent apples from turning brown:
- Add anti-oxidant substances like vitamin C. However, this method has a drawback, people can be poisoned due to excessive intake of vitamins.
- Isolate the oxygen and prevent chemical reactions from taking place, so the apple doesn’t change color. For example, pour some saltwater into a bowl of apples, spread over the apples, let them soak for two or three minutes. The enzymes in the apple cannot be combined with oxygen, the color of the apple will not change. The taste will not deteriorate, and saltwater can improve the nutrition of apples.
- Start with Apple. After research, it has been found that there is a type of polyphenol oxidase. Which plays an important role in the process of discoloration of apples. If this enzyme loses its activity. So the discoloration reaction will not happen. The scientists thought of directly turning off the gene that synthesized this enzyme. in order to develop an apple that does not change color.
The organic tannins in the apple flesh will also react chemically with the iron of the blade. Thereby creating a dark iron tannin covering the surface of the apple flesh. Due to which the cut surface of the apple will become discolored. Discolored apple flesh does not affect consumption, and a small amount of iron tannate does not harm human health. It’s just that the tannic acid in the pulp is difficult to dissolve in water, and if it is contaminated on a towel or handkerchief, it is difficult to wash it off.
People Also Ask
How to keep apples from turning brown?
Isolate the oxygen and prevent chemical reactions from taking place, so the apple doesn’t change color. For example, pour some saltwater into a bowl of apples, spread over the apples, let them soak for two or three minutes. The enzymes in the apple cannot be combined with oxygen, the color of the apple will not change. The taste will not deteriorate, and saltwater can improve the nutrition of apples.
Why do apples turn brown when exposed to air?
That the iron ions present in apples get oxidized to ferrous iron ions by O2 in the air. So the apples will turn yellow after peeling. Actually, it is not so. According to experiments, the “yellow-green” in the pale yellow-green sap is due to cytochromes. Not because of Fe 2+ plasma. The brown substance of the apple rind is a color reaction to phenolic compounds. Phenolic compounds (especially polyphenols) are easily oxidized to quinones, and quinones have colors.
Why apple turns brown?
The cut surface of the apple turns brown. Because many phenolic compounds in apple cells are oxidized to produce quinone compounds. Quinone is slightly soluble in water to brown the cut surface of an apple. Apples, pears, and some vegetables (such as potatoes, eggplant, etc.) not only appear brown after being peeled or bruised. It is also a result of the action of phenoloxidase.
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