Why is it that when leftover apples are left for a while, the bitten area will change color

This is mainly due to the discoloration reaction of phenolic-like compounds in the plant. After the phenolic compounds come into contact with the air, they are oxidized by the oxygen in the air to form quinones, that is, the discoloration reaction turns yellow, and the color changes from light to dark with the increase of the amount of reaction, and finally turns dark brown.

This oxidation reaction is the result of the release of phenol oxidase in the cell after contact with oxygen. Phenol oxidase is present in the organelles until the plant tissue is damaged, and oxygen from the air cannot enter, so no oxidative discoloration reaction occurs. When the bacterial tissue is damaged, the phenol oxidase is released and comes into contact with oxygen, and the discoloration reaction occurs.

Phenolic compounds include polyphenols, catechols, etc. Among them, polyphenols can be directly oxidized to form quinones; Catechols, on the other hand, polymerize under the action of phenol oxidase to form catechol polymers, which are dark purple, so the more polymers, the darker the section color.

This is true not only for apples, but also for peaches, eggplants, potatoes, etc., which also change color when they are cut. When the fruit changes color, the vitamin C content decreases, and the nutritional value is affected. If you don't eat it in time after cutting, you can soak it in salted water to prevent discoloration, so that it won't change color.

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To put it simply, the place that has been bitten is oxidized in contact with the air, and it changes color.

Sissy, because love has passed its expiration date, apples change color

One word... Oxidized, does not affect the consumption over

When apples are peeled, the phenols in plant cells are oxidized with the air under the action of phenols, producing a large amount of quinones. The new quinones can cause plant cells to turn brown rapidly, a change called enzymatic browning of food. So apples will change color after peeling and leaving them for a while.

This is also the case for apples and pears, as well as some vegetables (such as potatoes and eggplants). This browning affects the appearance of the food, reducing the nutrient content of the outer layer, but it is still edible. If the apple is left for a long time after peeling, the oxidative decomposition of plant cells in the air is intensified, the nutrients in the outer layer of the apple are decomposed more, and the pectin substances are further decomposed into pectin acid and methanol under the action of enzymes, making the flesh loose, moist, discolored, tasteless, and even rotten and deteriorated.

Apples can be eaten when they change yellow, apples are indeed easy to turn yellow, many people will find that some places have begun to turn yellow while eating, apples are yellow because of the oxidation reaction between the oxidase in the apple and the oxygen in the air, so it will change color, but the apple at this time does not produce toxic substances. If the cut apple is yellowed, the yellow layer can be peeled off, and the flesh below is not contaminated, and it can be eaten with confidence, even if the layer is not cut off and eaten, it is fine, but the nutritional value is reduced.

Because apples are rich in minerals, when you bite into it, it is easy to oxidize in the air when placed on the table, so it is easy to change color in the bitten area.

It is because the discoloration reaction is mainly due to the presence of phenolic compounds in apples, which are easily oxidized into quinones, and with the increase of the amount of reaction, the color gradually becomes darker, and finally it becomes dark brown.

This is because the bitten part of the apple comes into contact with the air and oxidizes, so it changes color.

Because of the oxidation in contact with the air, the phenolic compounds in the pulp react with the air, and the longer the contact time will become, the darker the color, if you want to change the color, you can soak it in water or plastic wrap, I hope it will help you.

Why is it that when an apple is eaten and placed on the table, the bite will change color after a while. I think the apple took a bite and put it on the table. After a while, the color of the apple will change color.

It's because there's no protective skin in the place where you eat. Apples are oxidized. So it's going to change color.

After the apple is bitten, it comes into contact with oxygen, and the fructose in it binds with oxygen, so it changes color.

Oxidation, the components inside the pulp will oxidize after air contact.

Why do apples change color after they are cut.

If you pay a little attention, you will notice that when the apple is peeled or cut and left for a while, the color of the cut surface will change from light to dark, and finally to dark brown. This is true not only for apples, but also for potato tubers, peaches, eggplants, etc., which also change color when they are cut. What's going on?

The discoloration reaction occurs mainly due to the presence of phenolic compounds in these plants. For example: polyphenols, catechols, etc.

Phenolic compounds are easily oxidized to quinones, that is, they change color and turn yellow, and the color gradually deepens with the increase of the amount of reaction, and finally turns dark brown. The oxidation reaction occurs due to the contact with oxygen in the air and the release of phenol oxidase in the cell.

Phenolic oxidase exists in organelles and cannot come into contact with phenolic compounds until the tissue is damaged, and oxygen in the air cannot enter, so no oxidative discoloration reaction occurs. When the cell tissue is damaged, phenol oxidase is released to contact with phenolic compounds, catalyzing the oxidation of phenolic compounds, coupled with the action of oxygen in the air, a discoloration reaction will occur. Among them, polyphenols can be directly oxidized to quinones and change color.

Catechol molecules, on the other hand, polymerize under the action of phenol oxidase. Two catechol molecules are linked together to form catechol dimers, which in turn can be joined in pairs to form tetramers. The individual catechol molecules and their dimers and tetramers are all colorless, but catechol tetramers can form multimers, which are purple.

So the more polymers are formed, the darker the color of the incision surface will be.

When apples change color, the amount of vitamin C will decrease, affecting the nutritional value. To prevent the apple from changing color after cutting, the best way to keep it out of contact with the air is to soak the apple in salt water.

This is an oxidation phenomenon;

Apple oxidation is mainly due to the oxidation of VC under the action of enzymes. The solution is: after the apple is soaked in water, put a little salt on the skin, and then gently rub the apple back and forth with both hands, the dirt on the surface can be rubbed clean quickly, and then rinsed with water, you can eat it with confidence.

Apples turn brown when they are cut into contact with air due to oxidation, so they can be soaked in salt water for about 15 minutes. Or drop lemon juice onto apple slices to also prevent apple oxidation and discoloration.

It is oxidized, like potatoes, and after being shredded and left in water, it will turn black after a while, so to prevent oxidation, put it in water and soak it immediately after cutting.

It's oxidized, and a lot of things are like this, like potatoes, eggplants, and whatever.

If you bite into an apple, you won't eat bacteria.

Normally, if it is oxidized, it is necessary to eat the apple in time to avoid bacterial invasion.

Apples contain bivalent iron ions, which are oxidized, and when apples bite open, they come into contact with oxygen in the air and oxidize to trivalent iron, which is brownish-yellow. So it will change color.

Ferrous ions are oxidized by air and reduced to 3-valent iron ions, which are fine after eating, but the human body cannot absorb them.

Due to the presence of bivalent iron ions in apples, they are oxidized, and when the apple bites into contact with oxygen in the air, it oxidizes to trivalent iron, which is brownish-yellow. So it will change color.

It's because the part that was bitten had a chemical reaction that met the oxygen in the air.