Why do apples change color, please everyone, thank you

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 dark brown. 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.

Drop a little lemon juice on the cut side of the apple to not only not change the color, but also maintain the original flavor. In addition, some fruits that are easy to change color can also be treated in this way, and the effect is excellent!

Because apples react chemically with the air and are oxidized by the oxygen in the air, of course, there are many molecules in nature (large gases). Other molecules may also react with apples!

Causes of discoloration: Although fruits and vegetables are picked, their internal metabolic activities have not stopped, various enzymes are still "working", when they are peeled or peeled, a polyphenolic chemical ——— tannins contained in their bodies, will react with oxygen in the air under the action of enzymes to produce quinone compounds, and the color of food will also turn brown.

This is because contact with oxygen in the air and the release of phenol oxidase in the cells occurs, and the discoloration reaction turns yellow. When apples change color, they contain less vitamin C, affecting their nutritional value. To prevent discoloration, it can be kept out of contact with the air, and the best thing to do is to soak the apples in salt water.

Because apples contain an element that oxidizes in contact with oxygen in the air and changes color, apples contain iron, and when exposed to air, the iron oxidizes, like rust. After the apple is plucked from the tree, it has been separated from its mother, but its breathing activity is still active. This is due to the presence of phenolic substances in apples, which maintain their respiration.

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.

So, it is best to eat the fruit immediately after peeling. An easy way to control the discoloration of apples when giving apples to babies is to immediately soak the peeled apples in cold boiled water, sugar water, or light salt water to isolate them from the air to prevent the oxidation of phenols in plant cells. However, from the point of view of preserving the nutrients in apples, peeled apples should not be soaked for too long.

Because apples contain a large amount of iron ions, when we peel apples and expose the apple flesh to the air, the iron ions will quickly react with oxygen, and the iron ions will change from negative bivalent to negative trivalent, which is oxidized, so the color will turn yellow, which is similar to the principle that iron will rust, which is the result of oxidation!

How it works:

We first open the phone and find the option "Settings", which is displayed on the main page.

Once you're in the settings, scroll down the page and find the generic option

Scroll down to find the "Accessibility" option and click on it.

Then look for the option to show "Show Adjustments".

Then find the Flip Color option and turn it off. So that our problem is solved.

If the screen turns yellow, one reason is that the eye protection mode is turned on. We can set it by "Settings" "- Display & Brightness". Q:

What is the first step after the iPhone arrives? It must be installed after activation, because the iPhone does not have a beautification function, so for people who love to take photos, the Meitu App is almost a must-install for beauty apps, but did you know? The iPhone's built-in optimization software is also very powerful, but many people don't know about this feature.

First of all, open a **:

You can see that this is a photo of the street after the rain, the trees on both sides of the street should have been emerald green after being washed away by the rain, but it was photographed dark green, such a ** obviously can't be sent to the circle of friends to pretend to be forced, what should I do? Do you see the setting button in the red circle at the bottom?,Click it and you'll enter the **page.。

After entering, you can see that there are rotation and cropping, filters, parameter adjustments, and more (graffiti) functions at the bottom, and the magic pen in the upper right corner is the automatic optimization function. Let's choose Auto-Optimize to give it a try and see how it looks before and after optimization.

It can be seen that the optimized trees have turned into emerald green colors, which is very beautiful, which is even better than the Meitu App. If you're not satisfied with one-click beautification, you can use the filter function, which has eight filters to choose from.

I believe that many friends are using Apple mobile phones, so if the color of Apple mobile phones changes during use, how should they be restored? On this issue, I would like to share with you my experience, I hope it can help you.

Tools Raw materials.

iPhone. Method steps.

1 6 Step by Step Reading.

Start by finding Settings on our mobile desktop and tapping on it.

Then find Universal and tap on it.

Then find Accessibility and tap on it.

Then find the display adjustment and tap on it.

Then find the color filter and click on it.

Finally, click the turn off color filter switch and you're good to go.

It may be that the function of inverting colors is enabled, and the method of recalling it is as follows:

1. Open your phone's settings and tap General.

2. Go to General and click Accessibility.

3. In the auxiliary function, turn off the button to invert the color, and then you can change back to the original color.

How to restore the color of the Apple mobile phone?

1. First, please open the "Settings" app on the screen.

2. In the settings list, find the "General" column and click to enter.

3. Then please find the "Accessibility" column in the general list and click to enter.

4. Then in the Accessibility Function, please check "Invert Color and Grayscale."

Two options, whether or not are open. If one of them is open, turn it off to fix it. I've turned on Invert Colors for now.