Many housewives know that cutting apples in advance is problematic - they can lose their original attractive appearance. What to do so that the apples do not darken. How to get around this problem. Let's figure it out - the tips have been tested by experienced chefs.

A way to prevent green fruit from changing color

Cut apples in the air begin to darken quickly. To prevent this from happening, before you start cutting apples, pour water into any bowl and squeeze lemon juice there. For 2 glasses of water - 2 tbsp. tablespoons of freshly squeezed lemon juice. Cut the apples into as many pieces as you need for the recipe. Place each wedge immediately in prepared water with lemon juice. Place apples in a colander before cooking.
The peel of apples contains many beneficial substances. If before no one thought about peeling apples or not, now, when apples are treated with various chemicals on top, this issue has become a problem.

The choice is here for each of us. If someone is willing to take the risk of receiving a dose of chemicals from the skin of apples at the same time as a dose of nutrients, then the peel need not be peeled. If one is not prepared for such a risk, then the peel should be peeled. However, in either case, the apples need to be rinsed well.
Unfortunately, when making mashed potatoes, compotes, preserves, jams and even apple juices, apples lose a huge amount of nutrients. It has been proven that only 10% of polyphenols and 3% of catechins remain in apple juice. However, if you put a whole apple in a blender, the resulting juice will retain all the nutrients. Unfortunately, this method of making apple juice is not used in the industry. Therefore, it is better to cook it at home.

The world around us is amazing. And if children understand this easily, then with age they get used to many things and happily forget about it. As a result, the simplest questions of a kid can confuse an adult. For example: "Why does the apple darken on the cut?" This process is very multifaceted, but not as simple as it seems at first glance. After all, different apples darken in different ways, and some do not darken at all.

Debunking myths

Most often, when asked about why an apple darkens on the cut, they hear that this is due to the iron contained in it. It is also known from the course of school chemistry that iron has a valence (or oxidation state) of +2 and +3. So, in apples, it has the first, however, after cutting, it begins to actively come into contact with the air, which contains oxygen. As a result, iron is oxidized to the +3 degree, thereby forming an oxide. It turns out that the apple simply "rusts". And the color is appropriate.

However, any chemist knows that this is not the case. One apple weighing about 150-160 grams contains only 3-4 mg of iron. Is that enough to ruin the appearance of a whole fruit? Of course not. In fact, completely different substances are responsible for this. After all, this happens with pears and bananas. But they don't have that much iron.

True reasons

So why does an apple darken when cut when there is practically no iron in it? After damage to the fruit, a number of chemical reactions take place, due to which it loses its presentation. But if you follow the whole chain, you can still understand the real reason.

As you know, apples, like any other fruit, are rich in antioxidants. From the point of view of chemistry, they belong to the group of polyphenols. They have different names, but their essence is the same - it is a combination of different phenols (not to be confused with poison). Of course, this substance in itself does not affect the color of the apple in any way, since it is simply colorless. But it also contains the enzyme polyphenol oxidase, which, after any damage, begins to actively interact with polyphenols. Oxygen is the main catalyst for the reaction. And as a result, quinone is formed in a huge amount in apples, and it is a strong oxidizing agent. This is the correct answer to the question of why the apple darkens on the cut.

How to fight?

Of course, many people do not like this property of apples. Fruits quickly lose their attractive appearance, and even fresh slices begin to look not very attractive in just a couple of minutes. Chefs have long come up with their own way of dealing with this shortcoming. To do this, just wipe the cut with a lemon peel or sprinkle with lemon juice. Another option is to dip the fruit in a citric acid solution for 1-2 minutes. As a result, the apple does not darken when cut.

For apple juice, another option has been invented. To do this, it is simply pasteurized for 20-30 minutes at 70-80 degrees. As a result, polyphenol oxidase is destroyed. This means that it is no longer possible to start the oxidation process in principle. Unfortunately, this method is not suitable for whole apples.

Scientific approach

Obviously, by removing one of the three components of the reaction, it is possible to ensure that the apples do not darken. Unfortunately, it is impossible to get rid of polyphenols. In addition, they are believed to be beneficial to the body. And the first thing that was achieved was to exclude oxygen from the reaction. To do this, the apples are covered with a special substance similar to wax (according to the international standard, it is marked E901-E913). True, it is advisable to wash off the coating before eating such fruits.

But science does not stand still. After all, it has long been known why an apple darkens when cut. The presentation of a new genetically modified variety proved that by removing the oxidizing enzyme, you can get just "eternal" apples. An excellent solution for supermarkets and restaurants. Moreover, this only required blocking some genes. It is believed that this technology is the most harmless.

Use lemon juice. Apples turn brown as the enzyme they contain reacts with the oxygen in the air. This process is called oxidation. Lemon juice can prevent oxidation because it contains citric acid, which is an effective antioxidant. You can use freshly squeezed or canned lemon juice. It is best to use this method only on sweet types of apples because lemon juice will add astringency. You can use lemon juice to protect apples from oxidation in two ways:

Use salt. Salt is a natural preservative and can effectively protect apples from oxidation. Make a solution of 1/2 teaspoon salt per liter of cold water. Place the sliced ​​apples in the solution and let them soak for 3-5 minutes. Remove from water and rinse thoroughly with a colander or sieve. The pieces will not oxidize for a while.

• Don't worry that the fruit may taste salty, if you don't use too much salt, don't soak the apple for too long and rinse it thoroughly afterwards, the taste of the fruit will not change.

When we cut an apple or peel it, it darkens. This process is triggered by the presence of an enzyme in the fruit called polyphenol oxidase (ascorbic acid oxidase). This enzyme causes darkening when oxygen interacts with the tannin substance found in apples.

Why does an apple darken on a cut: an answer to the question

When the fruit is cut, the cells that are directly on the cut immediately begin to interact with oxygen. Ascorbic acid oxidase causes discoloration of the apple surface when exposed to oxygen.

The fruit turns brown when exposed to air due to the oxidation process. The peel of an apple protects it from oxidation. But as soon as you make an incision in the fruit, its pulp immediately begins to oxidize and after a few minutes the apple darkens.

It is interesting to know that temperature conditions affect the rate of oxidation. For example, if you put a peeled apple in the refrigerator, it will only darken after a few hours or even after a day. If you put the fruit in a hot oven, it will turn brown in a few minutes.

By the way, sour varieties darken faster than sweet ones. This is due to the fact that they have more oxidase enzyme. For example, Granny Smith retains its light shade when cut longer than other varieties.

So that apples do not darken when slicing: life hack

If you need to prepare fruit slices, you are probably wondering how to prevent browning and make sure that the apple retains its beautiful color and juicy appearance.

Vitamin C will come to your aid , it is found in citrus juice. Simply brush the apple cut with orange or lemon juice. Vitamin C prevents the interaction of the tannin substance with oxygen, thus preventing browning. Keep in mind that when sprinkled with citrus juice, the apple will be sour.

If you don't want the apples to be sour, sugar syrup can help keep them from browning. We cook it according to a standard recipe, then dip in syrup or grease the cut slice with it. This method not only protects against browning, but also gives the fruit a sweet taste.

If there is no citrus juice or sugar syrup on hand, citric acid will come to the rescue. Add 1/4 tsp to cold water. citric acid stir until dissolved, then immerse the fruit for 10 minutes.

Sweet soda - it contains sugars and citric acid, they will prevent oxidation processes. Just drizzle some sweet soda over the cut of the fruit, you don't have to do anything else.

If you take an apple with you

This method is suitable for those cases when you need to take a whole cut apple on a trip, to work or school. ... We cut it into two halves and take out the core, then put them together again and tighten with a clerical elastic band. We pack in a bag.

Now you know why the apple slice darkens. If you want to preserve its freshness and beauty, use our simple life hacks.

Apples cut into pieces are included in recipes for many dishes - salads, pies, various desserts, etc. And the apple slicing itself adorns the table and attracts the attention of guests.

But, unfortunately, apple slices quickly, in a matter of minutes, darken on the cut, losing their appetizing fresh look. However, it is easy to do so that the apples do not darken when slicing: many different ways have been invented for this.

Why does the cut apple darken?

As you know, apple pulp contains a lot of iron. The most surprising thing is that this iron in apples is in a rapidly digestible state, which is why red apples, the richest in this element, are recommended for people with anemia.

But it is iron that causes the darkening of apple cuts: iron atoms react with oxygen in the air, forming iron oxide, which gives the pulp its characteristic brown color. So, to prevent browning, you need to prevent the apple juice from coming into contact with air.

Method 1 - lemon juice

To prevent the sliced ​​apples from darkening as long as possible, sprinkle them with lemon juice. For this, both freshly squeezed and canned juice are suitable. You can use a small spray bottle or pastry brush to evenly coat the slices with juice. This method works best for sweet apple varieties which, when combined with lemon juice, have a more sophisticated taste.

If you have sweet and sour apples at your disposal, it is better to prepare a mixture of lemon juice and boiled water, taking no more than a tablespoon of juice in half a liter of water. The apple slices are dipped in acidified water, kept in it for about a minute and discarded in a colander.

After such processing, the apple slice remains fresh for several hours. Instead of lemon, you can take lime, its juice has the same properties. If there is neither one nor the other, you can use a citric acid solution by dissolving a teaspoon of powder in a liter of water.

Method 2 - saline solution

Another available preservative is common table salt. A solution of a teaspoon of salt in a liter of water will also protect the apple slices from browning. You need to soak them in water with salt for several minutes, and then rinse thoroughly with clean water to wash off the salty taste. It is important not to overdo the apples in water so that the salt does not penetrate too deeply into the pulp.

Method 3 - carbonated lemonade

The composition of sugary carbonated drinks necessarily contains citric acid. Pouring soda over the apple slices for 3-4 minutes will keep them fresh and attractive for several hours.

You can rinse the apples after processing, or leave a light layer of soda on top to add flavor and aroma to the apples.

Method 4 - sliced ​​fruit freshener

Some supermarkets sell a special powder to combat darkening of fruit in the cut. It consists of a mixture of ascorbic acid and citric acid and can be prepared by yourself. Buy glucose tablets with ascorbic acid at the pharmacy, grind into powder and mix with citric acid. Sprinkle a small amount of the mixture over the slices and mix well to distribute the powder evenly.

Method 5 - blanching

In order to stop the oxidative process, apples can be blanched, i.e. dip in boiling water for a few minutes. For soft apples, one or two minutes in boiling water is enough, you can hold it a little longer. True, this method is not suitable for apple slicing, which is supposed to be served, as the apples will become too soft and slightly change the taste.

But if the slices go into the filling of a pie or are used as a component of a salad, blanching will be the best option. Having pulled the apples out of the water, they need to be thrown into a colander and rinsed with a cold stream, and then let the water drain.

Method 6 - cling film

If you cut off a half of a large apple and want to leave the other one for later, wrap it as tightly as possible in plastic wrap to block the air and put it in the refrigerator. If done correctly, the apple cut will stay fresh for 24 hours.

Instead of cling film, you can use a plastic bag with a "zip". Having put half an apple in it, you should carefully squeeze out the air from there and close the bag.

Method 7 - rubber band

This method is suitable for those who take a sliced ​​apple with them to school or to the office. The washed apple must be cut into slices, removing the core, and then fold these slices to make a whole apple again.

Now you need to carefully pull off the slices with an elastic band so that they do not crumble, and put them in a bag. After removing the cutters, the slices will turn out to be fresh, white and juicy, as if they had just been cut off.

The world around us is amazing. And if children understand this easily, then with age they get used to many things and happily forget about it. As a result, the simplest questions of a kid can confuse an adult. For example: "Why does the apple darken on the cut?" This process is very multifaceted, but not as simple as it seems at first glance. After all, different apples darken in different ways, and some do not darken at all.

Debunking myths

Most often, when asked about why an apple darkens on the cut, they hear that this is due to the iron contained in it. It is also known from the course of school chemistry that iron has a valence (or oxidation state) of +2 and +3. So, in apples, it has the first, however, after cutting, it begins to actively come into contact with the air, which contains oxygen. As a result, iron is oxidized to the +3 degree, thereby forming an oxide. It turns out that the apple simply "rusts". And the color is appropriate.

However, any chemist knows that this is not the case. One apple weighing about 150-160 grams contains only 3-4 mg of iron. Is that enough to ruin the appearance of a whole fruit? Of course not. In fact, completely different substances are responsible for this. After all, this happens with pears and bananas. But they don't have that much iron.

True reasons

So why does an apple darken when cut when there is practically no iron in it? After damage to the fruit, a number of chemical reactions take place, due to which it loses its presentation. But if you follow the whole chain, you can still understand the real reason.

As you know, apples, like any other fruit, are rich in antioxidants. From the point of view of chemistry, they belong to the group of polyphenols. They have different names, but their essence is the same - it is a combination of different phenols (not to be confused with poison). Of course, this substance in itself does not affect the color of the apple in any way, since it is simply colorless. But it also contains the enzyme polyphenol oxidase, which, after any damage, begins to actively interact with polyphenols. Oxygen is the main catalyst for the reaction. And as a result, quinone is formed in a huge amount in apples, and it is a strong oxidizing agent. This is the correct answer to the question of why the apple darkens on the cut.

How to fight?

Of course, many people do not like this property of apples. Fruits quickly lose their attractive appearance, and even fresh slices begin to look not very attractive in just a couple of minutes. Chefs have long come up with their own way of dealing with this shortcoming. To do this, just wipe the cut with a lemon peel or sprinkle with lemon juice. Another option is to dip the fruit in a citric acid solution for 1-2 minutes. As a result, the apple does not darken when cut.

For apple juice, another option has been invented. To do this, it is simply pasteurized for 20-30 minutes at 70-80 degrees. As a result, polyphenol oxidase is destroyed. This means that it is no longer possible to start the oxidation process in principle. Unfortunately, this method is not suitable for whole apples.

Scientific approach

Obviously, by removing one of the three components of the reaction, it is possible to ensure that the apples do not darken. Unfortunately, it is impossible to get rid of polyphenols. In addition, they are believed to be beneficial to the body. And the first thing that was achieved was to exclude oxygen from the reaction. To do this, the apples are covered with a special substance similar to wax (according to the international standard, it is marked E901-E913). True, it is advisable to wash off the coating before eating such fruits.

But science does not stand still. After all, it has long been known why an apple darkens when cut. The presentation of a new genetically modified variety proved that by removing the oxidizing enzyme, you can get just "eternal" apples. An excellent solution for supermarkets and restaurants. Moreover, this only required blocking some genes. It is believed that this technology is the most harmless.