If you do not have a plot of land where you grow potato, then you have to buy it in a store or in the market. Today, there are many people who want to sell potatoes, but choosing among the huge variety of vegetables one that will be of high quality and healthy is not at all easy.

Definitely buy potatoes best of all from a private trader who himself raised it, dug it out by hand, dried it, collected it and stored it in a dry cellar. On collective farms, potatoes are planted and dug up by special equipment, and the rules for planting and storage conditions are often violated. If there is poor ventilation in the room where the potatoes are stored, then the potatoes suffocate from lack of oxygen and this is the most common reason that the tubers turn black after cooking.

There is an opinion that blackening after cooking indicates that it contains a lot of substances harmful to health. For example, nitrates, mineral fertilizers and pesticides, which are used to combat the Colorado potato beetle and wireworm. Having studied the composition of tubers that turn black after cooking, experts came to the conclusion that the excess content of nitrates and pesticides does not contribute to the blackening of vegetables, but the main causes of browning of boiled or fried potatoes are improper cultivation and storage.

Our "second bread". It is the main ingredient in many dishes, we eat it daily. Potato tubers contain over 50 healthy elements, and from a medical point of view, potatoes are more necessary and appropriate for a modern person than any medicine. Indeed, it contains a lot of potassium, which has a diuretic property and normalizes cardiac activity, which is especially important in our age, when the number of patients with heart attacks and strokes has increased dramatically.

If during the growth of tubers potatoes there is not enough potassium, then you should not expect a big harvest. Therefore, in order to increase profits on collective farms, potash fertilizers are applied for potatoes, which contain a lot of chlorine. Chlorine easily penetrates the tubers, worsens the starch content, keeping quality and taste of potatoes. Experienced agronomists know that chlorine-containing fertilizers can only be applied for autumn digging, and in the spring it is better to fertilize the soil for potatoes with potassium sulfate.

If in the soil under potato they make a lot of nitrogen fertilizers and little potassium fertilizers, then synthesis is disturbed and amino acids accumulate in the tubers, including tyrosine, which is oxidized and forms melanin pigment. It is he who contributes to the darkening of potatoes before and after cooking. Based on this, it can be argued that the darkening of potatoes is often the result of a violation correct proportions fertilizers during cultivation, more precisely an indicator of a lack of potassium and an excess of nitrogen.

Of course, considering the fact that Russian potatoes is a staple food and many people buy it in bags in the fall, no one will recommend completely abandoning the use of potatoes if they darken after cooking. But to say that such potatoes are absolutely harmless to health and can be safely eaten is extremely wrong.

After all, the darkening potatoes- this is a sign of a violation of the rules for its cultivation and storage, as a result of which there have been changes in the composition of the root crop and its useful properties have been lost. To check whether a potato that changes color to black when cooked is dangerous to your health, try boiling it by adding 2-3 pcs. to water. bay leaves. If the tubers turn black in this case, then it is better to refuse to use this potato so as not to harm your health.


Choose high quality and tasty potato pretty hard. It happens that outwardly the tubers are beautiful and healthy, but when you cook it, the potatoes darken and taste like soap. The taste of a potato depends on its starch content. Varieties with a high starch content are crumbly and cook quickly, while those with a low starch content are more suitable for frying.

Unfortunately, no ways to understand when choosing a potato in the market or in a store that it will turn black when cooked, no. But there are still a few rules to avoid buying unhealthy potatoes:

1. Potatoes, which contain a lot of nitrogen and little potassium, are usually sticky, moisture just oozes from it. When buying, try to break off a small piece of tubers with your fingernail, if the fingernail enters it easily and silently, then this indicates that the potato was stored incorrectly, contains a lot of moisture and was grown incorrectly. A high-quality potato is elastic, when its skin is torn, a characteristic crack is emitted.

2. Never buy potatoes in bags if they are wet. Such a root crop, most likely, was stored in the wrong room or grown in swampy soil, because of which it contains a lot of moisture and will quickly deteriorate. Also avoid buying potatoes with a greenish skin, this is the first sign that they have been lying under the sun for a long time, and under the action of light a poisonous substance, corned beef, has formed in it. Eating green potatoes in large quantities can even poison you.

Housewives who buy vegetables in the store are often interested in why potatoes after or during cooking covered dark spots. Wherein getting dark not the whole tuber, but separate areas of blue-black color appear, similar to bruises. What can cause this phenomenon? Most often, they put forward a version of an excess amount of nitrates and other chemicals, or they cause it to be improperly stored. But, sometimes, exactly the same potatoes grow in their own garden plot, despite the correct agricultural practices.

main reason

Potatoes that change color when boiled are quite common. And the sight of such tubers does not cause appetite at all. The cause of dark spots on boiled potatoes is the lack of potassium in the fruit. The process of occurrence of dark spots is explained as follows:

While still in the ground, potato tubers accumulate chlorogenic acid, which, during the cooking process, forms dark spots when combined with iron ions. Why doesn't the color change completely? This is explained by the fact that chlorogenic acid is unevenly distributed in the tuber. In places of its greatest concentration, those very “bruises” appear. Normally, spots do not form. This is prevented by citric acid, formed under the influence of potassium in tubers.

To solve this problem, it is possible to propose the introduction of chlorine-free potassium fertilizers into the soil. If sand predominates in the composition of the soil, fertilizers are washed out in a short time, it is preferable to feed with potassium as the potatoes grow.

Other causes of browning potatoes:

  • The deterioration of the quality of tubers also occurs when the soil is poorly saturated with oxygen (this is especially important during the active formation of tubers). This phenomenon is typical for clay soils oversaturated with moisture.
  • The cause may also be improper storage in a warm, humid room at temperatures above 7 ° C.
  • It happens that potatoes become stained before cooking, during the cleaning process, also in separate areas. The reason for this is the compounds in the composition of the tuber, the oxidation of which occurs in the air. Their uneven distribution in potatoes is caused by drought and insufficient watering.
  • The dependence of darkening on the introduction of a large amount of nitrogen fertilizers into the soil was also revealed. This confirms that the main cause of browning is still an excess of nitrates (not excluding other causes). And when manure is applied, such a phenomenon is almost excluded.

Culinary trick!

So that the potatoes do not darken during cooking, you must add citric acid(a quarter of a teaspoon), you can put a couple of bay leaves.

What to do so that "bruises" do not appear?

  1. Apply nitrogen fertilizer moderately, or feed only with manure.
  2. Prefer chlorine-free potash fertilizers.
  3. Try to water regularly, especially in the absence of rain.
  4. Store potatoes at low temperatures (0°C to 7°C)
  5. Make your choice in favor of varieties that are not prone to staining. These are such as: Ariel, Impala, Condor, Arrow and others.

Potatoes have long been recognized by scientists as one of the most useful plants for humans. Its tubers contain a variety of vitamins and minerals. Even if there is only a certain time of it, the condition of a person will not worsen from this. For many lovers of this root vegetable, there is only one problem - why the potato turns black after cooking, but otherwise, this is one of the most versatile foods.

The plant has long been considered a second bread for many peoples. People eat it daily, list national dishes from potatoes is huge. Approves its use and modern medicine. Especially important is the fact that the tubers are high in potassium, which is beneficial to the heart and has a diuretic effect.

So that during growth the potato bush does not experience a deficiency of potassium and gives a good harvest, special fertilizers are applied to the soil. In autumn, without fail, chlorine-containing potash fertilizers are scattered on the site, then they are dug up before winter. If you need to improve the composition of the soil in the spring, then potassium sulfate is used for this.

If, on the site, the land is treated mainly with nitrogen fertilizers, do not add potash or make very little of them, which will not meet the required standards, then a violation of the synthesis of substances will certainly occur. As a result, amino acids accumulate in large quantities, and most importantly, tyrosine, which, when oxidized, produces melanin, which contributes to the fact that potatoes with its high content darken some time after peeling and cooking.

Based on the data obtained, it can be said that the darkening of potatoes during processing indicates that the proportions of fertilizers applied to plants were not respected during cultivation. Perhaps the soil was oversaturated with nitrogen and lacked potassium.

Refusing to eat potatoes just because they darken after peeling and boiling is not worth it. Indeed, for many, this is the main product on the table. But still it is worth taking into account some facts:

  • the darkening of potatoes indicates a violation of the rules for growing and storing;
  • the composition of the root crop has undergone a change, part useful properties lost;
  • you need to put a few bay leaves in a saucepan in which the potatoes are boiled, if after that the root crop has darkened, consider whether it is worth eating it.

A strong darkening indicates that the composition of nutrients in the tubers has changed significantly. Even if this did not affect the taste, such potatoes should not be eaten.

To have a tasty lunch healthy dish from potatoes, you need to be able to choose it correctly. Even large tubers can have an unpleasant soapy taste after cooking and darken soon. Potatoes can have different flavors. It depends entirely on the variety. Potatoes containing a lot of starch are crumbly, have a short cooking time, and those with a low content are used mainly for frying.

A potato that meets all the requirements is elastic, and when its skin is torn, a soft crack is heard. Don't buy wet potatoes. Such tubers are grown in violation of technology or stored incorrectly. Most likely, the entire crop will quickly deteriorate.

You can not buy potatoes with green spots. This means that she was exposed to prolonged exposure to sunlight, corned beef was formed in her - a very toxic substance. In addition to the fact that the taste of such potatoes has deteriorated, eating it in significant quantities can lead to poisoning.

What needs to be done so that the potatoes do not turn black during cooking?

Experts say that it is still possible to eat potatoes blackened during cooking. Moreover, this happens not only because of an overabundance of minerals in its composition. Sometimes it all depends on the soil on which it is grown, the variety of potatoes and weather conditions.

In order to understand why the potato turns black after cooking, as well as, it is necessary to inspect it and soak it in water. For people with heart disease, it is important to reduce the starch content, you can even crumble potatoes and change the water several times within two hours. Part of the starch will wash out and remain at the bottom of the container. When cooking, you need to use a bay leaf. If there are no problems with digestion, when boiling, add one tablespoon of table vinegar to one liter of water. You need to cook such potatoes with the lid closed.

A good housewife's nightmare: sumptuous, lovingly prepared mashed potatoes as it cools, it begins to darken, acquiring an unappetizing bluish-gray tint. The same thing sometimes happens with boiled, stewed and fried potatoes. To avoid such misunderstandings, consider the reasons for the too rapid darkening of tubers and methods for solving the problem, depending on the situation.

Undercooked potatoes turn black very quickly. Also, the pulp may darken if, when cooked in an aluminum dish or enamel saucepan with chips. Containers with damaged enamel are generally not recommended for use for cooking.

Peeled potatoes in the air almost always change color, but in some cases they remain light for a long time, and then only turn slightly pink, in others, the flesh almost immediately becomes dark gray. The speed and degree of darkening of the tubers during cleaning depends on the variety and growing conditions of the tubers.

Most often, potatoes turn black when grown with too much nitrogen fertilizer and too little potash. Excess nitrates are concentrated under the peel. Therefore, the tubers should be thoroughly washed, the peel cut off in a thick layer, and the peeled potatoes should be immediately immersed in cold water and kept for 2–4 hours. Of course, the tubers will lose a lot useful substances, but along with them - and part of the nitrates.

Nitrates are the main reason for the rapid browning of potatoes after slicing.

An additional benefit of this procedure: if the potato slices lie in the water, there will be much less starch left. Therefore, when frying, the pieces will not soften, but will be covered with a golden crisp. Before frying, the pieces must be laid out on a paper towel to remove moisture.

You can prevent the darkening of tubers intended for mashing by putting 2-3 bay leaves in the cooking water. And a few peas of black pepper will fight off the unpleasant smell that appears on potatoes that have lain in storage for too long.

A little reference on "kitchen chemistry": the tubers turn black due to the fact that when heated, a reaction occurs between the iron compounds contained in them and chlorogenic acid. You can avoid this if you create in a saucepan with heat treatment acidic environment.

So that the potatoes do not turn black during cooking, you need to add a tablespoon of vinegar to the water, lemon juice or a little citric acid (on the tip of a knife). Tubers cooked in this way will retain their shape better. If the potatoes are stewed, then something sour, for example, sour cream or mayonnaise, can also be added to the gravy.

Blackening of potatoes during storage

If the storage conditions are violated, the tubers may suffer:

  • freeze;
  • turn green;
  • get melanosis.

If the potatoes turn black during cooking, the tubers may have frozen during storage. Frozen potatoes have an unpleasant sweetish aftertaste that does not disappear during frying and stewing. A damaged vegetable is suitable only for soups or borscht, and it should be cooked separately, with the addition of vinegar (a tablespoon per liter of water).

When heated, the green potatoes, which have been lying in the light for a long time, darken very quickly. It makes no sense to cut off the areas that have changed color: green potatoes are not only unpleasant in taste, but also contain a large amount of a toxic substance - solanine. It is best to discard such tubers immediately.

Melanosis is a disease in which blurry gray spots are found under the skin of an apparently healthy potato. Sick tubers remain edible, but they do not look appetizing at all. To prevent them from darkening even more during cooking, vinegar, citric acid or bay leaf are added to the water.

Melanotic spots on potatoes occur in places of bruises and injuries. Starchy varieties are especially susceptible to disease. Melanosis can also be the result of too early harvesting of potatoes or, conversely, the fact that they have been lying in dry, warm soil for too long. In order to prevent melanosis of tubers, the crop must be harvested carefully, trying to avoid cuts and scratches, and during transportation - do not throw or squeeze.


Potato melanosis

After harvesting, potatoes should be stored in a warm, well-ventilated area (optimum temperature is from +15 to +18°C). There it must lie for at least three weeks: during this time, the peel of the tubers will become coarse, and small scratches will heal. Then the potatoes are moved to storage, where the temperature is gradually reduced to + 4–6 ° C.

The storage must have a ventilation system: the tubers need to "breathe", otherwise they will get wet, and the pulp will start to darken. If the storage temperature rises or falls sharply, condensation forms on the skin of the potato, which also contributes to melanosis. So that the potatoes do not rot, you need to spread the beets on top in a thin layer: this vegetable absorbs excess moisture.