The pages of cookbooks focus mainly on taste and appearance ready meals, but not a word is said about the chemical composition of food. But even if the dish looks appetizing, if some rules for the preservation of nutrients are not followed, it will not bring a person any benefit. What tricks should a real hostess know in order to cook healthy and appetizing food at the same time?
The main task of the hostess is to preserve vitamins in products when cooking and storage. Nutrients are preserved only with gentle processing, which does not require long heating processes, otherwise 10 to 15% of biologically active substances can be lost.
Food defrosting rules
- Thawed fish and meat should be subjected to immediate heat treatment, which will preserve the main vitamins that make up their composition;
- Food products after defrosting should not be frozen again, since after that they will lose almost all nutrients and lose their taste;
- Meat products should only be cooked after they have been completely defrosted. Otherwise, the loss of vitamins and minerals that make up their composition is guaranteed;
- When defrosting food, one should not lose sight of the fact that rapid defrosting leads to the loss of biologically active substances. That is why it is necessary that they thaw at room temperature;
- If frozen foods are thawed in water, then there is a significant loss of the main food ingredients, which is accompanied by an intensive reproduction of microorganisms.
Heat treatment rules
Heat treatment contributes to the violation of the biological value of food products, the structure of their tissues, biochemical bonds, and also reduces the amount of minerals, enzymes and vitamins that make up the composition. As a result of such changes, food loses its properties, as it becomes less useful for the human body.
When frying, there is a strong heating of fats, which affects the biological and nutritional value processed product depressing effect. These are not all the disadvantages of this treatment, since frying contributes to the production of carcinogenic substances that adversely affect internal organs human, causing various diseases. This type of cooking is the most imperfect and "old-fashioned", as it contributes to the loss of the nutritional value of food and only harms the human body.
During cooking, much less biologically active substances are lost and microbes are destroyed under the influence of high temperatures. Food prepared in this way has a more natural taste and is better absorbed by the body. When steaming, almost all vitamins are also preserved, which can only be compared with baking. This type of heat treatment can also be called gentle, since during its implementation the change chemical composition food is almost non-existent.
- When cooking, use the minimum amount of water, just enough so that the food is only lightly coated. It is preferable to steam vegetables, as some vitamins are lost during cooking;
- Legumes should be soaked for a while before cooking, which will reduce the cooking time. The product must be boiled in the same water in which they have been for several hours;
- Cereals must be cooked in strict proportions of 1: 2, since during heat treatment some of the vitamins pass into water and it is irrational to drain it;
- Whole-cooked vegetables allow you to save almost all vitamins, and when preparing mashed potatoes, about 20% of biologically active substances are lost;
- In order to preserve the nutrients in foods, they must be placed in hot water or placed on a preheated baking sheet. It is also more expedient to cook foods unpeeled and uncut, that is, whole and with a peel;
- Food should be cooked only in enameled dishes, since any metal can cause a change in the chemical composition;
- Jam should be cooked for no more than 5 minutes, the so-called "five-minute" which allows you to save nutrients and enjoy this product in the winter.
Currently, it is most rational to cook food in a slow cooker, since this method is the most gentle heat treatment, in which there is practically no change in the chemical composition of nutrients. In a slow cooker, you can save almost all vitamins and minerals in their original quantity.
The reaction of food components to heat treatment
Housewives who want to preserve the maximum benefit in products during cooking should know not only their composition, but also how vitamins react to various cooking methods. Different groups of nutrients are boiled, fried, boiled and thawed differently.
Ascorbic acid is the most unstable element, which is already destroyed at 60°C. This vitamin is adversely affected by sunlight, long-term storage and high humidity. You cannot cook jam from berries and fruits, which include this element, since the finished product will bring little benefit. Vitamin A is resistant to high temperatures, but oxidizes at room temperature and is not altered by ultraviolet rays.
Chicken legs in a slow cooker
Vitamin D does not change when boiled in an acidic environment, but is destroyed in an alkaline one. Vitamins of group B practically do not change when exposed to culinary processing. It is possible to destroy these elements only with prolonged boiling. Therefore, cook the products in which they are included, should be on moderate heat, for a certain time.
Vitamin E can be subjected to heat treatment for any time at any temperature, as this element is resistant to heat. Vitamins PP, A and D are almost completely preserved during cooking and baking, so fruits and berries, which they are part of, are simply irreplaceable in compote. Jam from these products, rich in heat-resistant elements, helps to replenish the vitamins that a person lacks throughout the winter.
The film of fat contributes to the preservation of nutrients, which even when frying allows you to save some of the vitamins and minerals in food. Sugar also has a stabilizing effect, which is why jam is rich in basic food ingredients.
Despite the fact that jam allows you to preserve vitamins in berries and fruits for a long time, today freezing these products is more popular. When freezing, you can save not only vitamins A, D and PP, but also ascorbic acid in the original amount.
1. Changes in the heat treatment of fat-soluble vitamins.
2. Changes in the heat treatment of water-soluble vitamins.
1.Vitamins are divided into two groups: fat-soluble and water-soluble. The first group includes vitamins: A (antixerophthalmic) and its provitamin carotene, D (calciferol), E (tocoferol), K (promoting blood clotting), p (polyunsaturated fatty acids).
Vitamin A- By its chemical nature, it belongs to unsaturated cyclic alcohols. They are especially rich in animal liver, cow butter, egg yolk. In the body, it can be formed from carotene - colored foods found in carrots, peppers, tomatoes, green vegetables.
During heat treatment, the activity of vitamin A almost does not decrease; during frying, its loss usually reaches 15-20%. When frying the liver, the loss of A-vitamin activity is not large, and even when making a pate, it does not exceed 2-5%. Therefore, liver dishes are a good source of vitamin A. The loss of carotene during sautéing carrots does not exceed 20%. When storing passivated vegetables in a sealed container and in a thick layer for two days, the loss of carotene is: at 0-2˚-15-17%, at 12-13˚-20-25%.
Vitamin A is destroyed by ultraviolet rays.
vitamin D is the richest fish fat, it is also found in egg yolks, butter. Vitamin D is resistant to oxygen and heat, but not higher than 100˚.
Vitamin E(tocopherol) plays the role of a natural fat antioxidant. When heated, even in the presence of oxygen, it is stable, but is destroyed by ultraviolet rays.
Vitamin K found in the green parts of plants, liver, kidneys, but a significant part of the need for it is covered by the synthesis of its intestinal microflora. It is stable when heated in an acidic environment, but is easily destroyed in an alkaline and under the action of ultraviolet rays. Therefore, you should not store greens in the light, add soda when cooking green vegetables.
2. Water-soluble vitamins include B vitamins (B 1 - thiamine or aneurin, B 2 - riboflavin, PP - nicotinic acid and its amide, in in- pyradoxine, Bs - pantothenic acid, H - biotin, inositol, choline, folic acid, B 12, B 15) and vitamin C.
These vitamins are largely transferred into water during the cooking process, and if the decoction is not used, then their loss due to dissolution can be 20-30%.
Vitamin B 1 persists when heated in an acidic environment (pH about 3); as the acidity decreases, its losses increase. The most important sources of vitamin B 1 are bread, potato dishes, meat, liver, chickens, chickens, eggs (especially yolks).
Vitamin B 2- Resistant to heating in an acidic environment and rapidly decomposed in an alkaline environment. The most important source of it are dishes from the liver, kidneys, heart, eggs (yolks).
Vitamin pp found in potatoes, bread, liver, kidneys, mushrooms. During cooking, it is practically not destroyed, but its loss can occur due to dissolution in water.
Vitamin B 6 found in many fish and meat products, in legumes (beans, peas). It is resistant to heat, but unstable to light and oxidizing agents.
Choline stable during heat treatment; found in egg yolks, brains, liver.
folic acid poorly soluble in water, resistant to thermal effects. Sources of acid are leafy green vegetables, eggs, liver, yeast, and other foods.
Vitamin B12 found in the liver, kidneys, heart, meat, poultry, eggs, etc. It is stable when heated (pH about 7), in an alkaline environment (pH-8-9) losses increase, and under the action of light it is destroyed. Losses during cooking products usually do not exceed 10%. Thus, B vitamins are stable; during heat treatment, on average, they are preserved up to 70-80%. However, it should be remembered that these vitamins are water-soluble and easily pass into a decoction. When boiling peas, for example, it goes into a decoction up to
12% vitamin B 1.
Vitamin C (ascorbic acid) is less stable than other vitamins.
Plant foods contain provitamin C, called
ascorbigen, from which vitamin C can be formed. When plant tissue is damaged, the conversion of ascorbigen to ascorbic acid usually increases in it, and therefore vitamin C can sometimes accumulate in chopped vegetables during storage. This is observed in potatoes and onions, to a lesser extent in carrots , pumpkin, cabbage and does not occur at all when storing chopped cucumbers, zucchini, turnips. The synthesis of vitamin C occurs at an air humidity of 85-95% and an elevated temperature (up to 30-35˚). Ascorbic acid spontaneously oxidizes in alkaline media. In an acidic environment, oxidation occurs only under the action of catalysts. Therefore, to preserve vitamin C, it is desirable to maintain an acidic reaction.
Catalysts for the oxidation of vitamin C are salts of heavy metals (iron, copper, etc.) and enzymes contained in products. Therefore, during processing, contact of vegetables with iron and copper should be avoided in every possible way. Rubbing raw and boiled vegetables through metal sieves and passing them through a meat grinder have a particularly negative effect.
To quickly destroy enzymes that oxidize vitamin C, vegetables should be immediately immersed in hot water.
When vegetables are frozen and stored, their vitamin activity decreases slightly, but when vegetables are thawed, vitamin C is destroyed quickly. Therefore, frozen vegetables should be processed before thawing if possible.
Since the destruction of vitamin C occurs by oxidation, products should be protected from the action of oxygen, namely:
1) do not store pickled products without brine;
2) select dishes for cooking food according to the volume of servings so that it is completely filled;
3) cook food in a sealed container;
4) put vegetables in dishes in such a sequence that they reach readiness at the same time and do not undergo heat treatment for too long, since oxidative processes are especially active at high temperatures;
5) avoid adding water to food, and if this is unavoidable, then add boiled water, since raw water contains dissolved oxygen, and chlorinated and the strongest oxidizing agents are oxygen
Consuming a lot of greens fresh vegetables and fruits, we believe that our body receives a shock dose of vitamins. In fact, it turns out that not everything is so rosy. Vitamins are very unstable compounds. To preserve vitamins in food, you need to know: how to properly store food, how to prepare it for cooking, and what method of heat treatment to choose.
1. Ensure proper storage!
Try to store vegetables and fruits in a dark place, as vitamins are quickly destroyed under the action of light. Fresh greens are especially sensitive to light.
Do not create a large supply of vegetables and fruits. After three days of storing vegetables and fruits in the refrigerator, a third of the vitamins are destroyed. Storage at room temperature accelerates this process even more, leaving about half of the vitamins contained in the products.
Drying or freezing vegetables, berries and fruits also reduces the content of vitamins. To keep the maximum amount of nutrients in berries or fruits, it is best to wipe them with sugar. And in the process of harvesting, give preference to the old-fashioned way: grind them with a wooden crush in a wooden container.
Storing or cooking vitamin-containing foods in metal containers destroys the vitamins. For cooking vegetables and fruits, it is better to use glassware or stainless steel dishes.
2. Wash, but do not soak!
Do not soak vegetables and fruits, just rinse them under running water before cooking. Soaking is possible when vegetables and fruits are heavily soiled. At the same time, try to use the minimum amount of water for soaking and do not keep them there for more than 10 minutes. A large amount of water and prolonged soaking contributes to the transition of more vitamins and minerals from food to water.
3. Do not pre-clean!
The maximum amount of vitamins is located directly under the peel, so try to cut off a thinner layer of the peel. And it is advisable to peel vegetables and fruits, cut salads immediately before cooking or serving. As soon as you peel or cut vegetables and fruits, they begin to break down useful material. Vitamins A and C have the least stability, they are destroyed especially quickly.
4. When cooking
Water should cover the vegetables, if the liquid has boiled away, it is recommended to add only hot water. If add cold water, then oxygen will be supplied with it, destroying vitamins. For the same reason, the lid of the pot must be tightly closed when cooking.
If you are using frozen vegetables for cooking, do not defrost them before putting them in the pot.
Load the food into the pan not all at once, but gradually. The foods that take the longest to cook are loaded first.
Despite the fact that some of the vitamins are destroyed during cooking, the benefits of such vegetables are quite large. Pectins and fiber contained in vegetables reduce the content of harmful cholesterol in the blood and improve the digestion process.
5. Vitamins don't like frying!
The longer we cook food, the less vitamins remain in them. Therefore, in order to reduce the cooking time, give preference to sealed pressure cookers, where the products are cooked faster, which means that the loss of vitamins will be minimal.
They do not like vitamins and frying, better ways to preserve vitamins are or steaming. And it is better to cook vegetables unpeeled and as a whole, thereby you will lose much less nutrients.
Rules for the preservation of vitaminsRules for the preservation of vitamins
What food contains vitamins: "rich" food
Nowadays, if you ask a person the question: “How do you eat?”, Most often you can hear: “I eat well.” - "And what do you eat?" - “A lot of meat, caviar, smoked meats, chocolate, sweets, biscuits ...” These products, along with salt, spices, refined white flour, alcohol, have been considered a luxury from time immemorial, making up a constant diet only for very rich people. Today, the situation seems to have changed for the better: almost everyone knows what kind of food contains vitamins, and many are trying to enrich their diet with such products.
Rules for the preservation of vitamins in the culinary processing of products
Just choosing foods that contain vitamins is not enough. It is important to keep them in the cooking process. Another reason for insufficient intake of vitamins in the body is improper culinary processing of food: heating, canning, smoking, drying, freezing, storage in metal utensils, etc. But most of the year, the inhabitants of our country eat vegetables and fruits frozen, stored for a long time or grown in greenhouses!
What to do? How to save vitamins when cooking, because they are so necessary for our health? Here are some simple but effective tips for the hostess on how to preserve vitamins in food during heat treatment.
Rule 1. Vitamins in vegetables and fruits are located directly under the peel, so when cleaning them, you need to remove as thin a layer as possible.
Rule 2. Vegetables and fruits must be stored in well-closed earthenware or porcelain dishes in a dark, cool place (cellar, refrigerator, but not in the freezer).
Rule 3. Vegetables and fruits cannot be stored peeled without water. And even observing this rule of preserving vitamins, vegetables and fruits should be kept in water only for a limited time.
Rule 4. The larger the vegetables are cut, the less the loss of vitamins, therefore, if possible, they are boiled whole.
Rule 5. To reduce the loss of vitamins, it is better to stew or steam vegetables for a minimum time in a small amount of water (tomatoes, onions - without water) in a hermetically sealed fire-resistant glass dish. Guided by this rule of preserving vitamins during cooking, it is better to cook vegetables and potatoes in a pressure cooker. If it is not available, in any other dish, except for aluminum. Oil should be added when the vegetables are ready. The water in which the vegetables were boiled is best used, as it contains most of the mineral elements and vitamins. Food should not be overcooked.
Rule 6. When cooking vegetables, they must be placed in boiling water to reduce the action of enzymes that destroy vitamins and especially vitamin C.
Rule 7. Boil and stew vegetables should be in a container with a tightly closed lid, to prevent rapid and excessively long boiling.
Rule 9. The longer vegetables and fruits are stored, the less vitamins they contain. For example, the content of beta-carotene (a precursor of vitamin A) in carrot roots decreases by 4.75 times over 5 months of storage.
Rule 10. Fruit juices should be drunk fresh, vegetable juices can be stored for 10 hours in a closed earthenware or porcelain dish. Fruits and vegetables should preferably be eaten raw, after washing them thoroughly.
By following these rules for preserving vitamins in food, your diet will be healthier, richer in nutrients.
Vitamin C is one of the most unstable vitamins. How to save this vitamin in food?
After cleaning and chopping vegetables, immediately boil them by immersing them in boiling water;
Use only enameled dishes for cooking;
Protect from oxidation with heavy metal salts by adding starch, onion phytoncides, rye or buckwheat flour;
Cook under a lid at a slow boil in a stainless steel dish filled to the top, enameled dishes (steam is best);
Do not add baking soda;
Do not rinse sauerkraut;
Do not store vegetable dishes;
Do not digest, do not cook again;
Use decoctions of vegetables.
Nikolai Mikhailovich Amosov - the famous Soviet surgeon, academician, author of many popular books on health - notes in one of his works: "The best food is peasant food." And this is no coincidence. The diet of representatives of the middle classes and ordinary people has always included "black" bread made from unrefined wholemeal flour, natural vegetables and fruits that were grown in their garden, legumes and cereals. Everything that could be collected in the forest (mushrooms and berries) was eaten.
In fact, the food of the common people was the same food rich in vitamins, because it consisted of healthy and healthy foods with a high content of fiber and minerals. The poor, without thinking about it at all, simply “spoiled” their body, giving it everything it needs for its clear and proper functioning.
In our age - the age of culinary excesses, when people prefer to quench their thirst with Coca-Cola, and their hunger with fast food - there is hardly any doubt that a large part of the population suffers from malnutrition and vitamin deficiencies. Of course, today it is difficult to meet a patient with scurvy or beriberi, but this does not mean that modern man getting enough vitamins. Very often occur hidden forms vitamin deficiencies, which can manifest themselves in the form of a decrease in efficiency, increased fatigue, deterioration in mood, and so on.
Proper food storage. Losses * * of vitamins during the storage of products and their culinary processing are very large and in some cases reach 90%.
The greatest losses of vitamins occur during the storage of vegetables, fruits and berries. Oxygen in the air, increased temperature and humidity contribute to the destruction of vitamin C and, to some extent, vitamin A. Since vitamin C is the least stable vitamin, the measures that contribute to its preservation also largely preserve other vitamins contained in food products.
Maintaining proper and constant temperature and humidity in vegetable stores is required to preserve vitamins in fruits and vegetables.
In rooms for storing potatoes, the temperature should be between +2 and +3°C.
Fresh cabbage should be stored at -2 to +1°, sauerkraut from +3 to +4°; tops and greens from 0 to +2°. Relative Humidity air in vegetable * storage should be in the range of 85-90%gt;.
Various greens (sorrel, nettle, tops, etc.) are not recommended to be stored for more than 12 hours. Even with best conditions storage of greenery loss of vitamin C and carotene reach 30Vo, and sometimes even exceed this level.
Other food products during storage also lose some of their vitamin activity, but to a much lesser extent.
Preservation of vitamin o.v in flour and bread. Bread is one of the good and, moreover, the most common sources of B vitamins. Therefore, the preservation of vitamins in bread is one of the most important tasks in combating vitamin losses.
A schematic section of a grain of wheat is shown in fig. 19. Here 1, 2 and 3 are the fruit and seed coats and alheiro, a new layer, which together make up about 12% of the weight of the grain: the germinal part (5 - shield, 6 - sprout and 7 root) weighs 1-1.5% . The inner part 4 is the so-called endosperm, (seed protein; about 70-73% by weight) and the rest is water (12-15% by weight). The largest amount of vitamin Bi is found in the scutellum of the embryo.
The best varieties wheat flour obtained in mills with millstones contains 6-7 times more vitamin Bi than flour of 72% grinding obtained in roller mills. When grinding on millstones, a significant part of the aleurone layer and germ containing vitamins gets into the flour.
Vitamin B2 (riboflavin) is distributed in the grain in much the same way as vitamin Bi. Most of it is contained in the embryo and much less in the protein of the seed.
Vitamin PP (nicotinic acid), apparently, is concentrated mainly in the outer parts of the grain (in the aleurone layer). Thus, in flour of the highest grades, which does not contain shells and the germinal part of the grain, there are very few vitamins Bb, B2 and PP
With an increase in flour yield from 60 to SStyo, the content of these vitamins increases significantly. With an increase in the amount of flour obtained from the same amount of grain, the content of ground shells and grain germ increases in it.
Varieties of bread made from wholemeal rye and wheat flour do not need fortification.
Heat treatment has little effect on the content of riboflavin and nicotinic acid in bread, but it affects the content of vitamin Bb When bread is baked, depending on the variety, 10-30% of this vitamin is lost. Good material soy flour can be used to enrich flour with B vitamins.
Preservation of vitamins in meat. For long-term preservation of B vitamins in meat, it is best to freeze it from -10 to -5 °. Frozen meat can be stored for a very long time in the form of blocks placed in double containers (boxes) made of corrugated cardboard. This is especially important for the Far North, as it facilitates the importation of meat there for a long time.
With prolonged storage of canned meat, significant losses of B vitamins, especially vitamin B*, occur in them. When cooking meat, up to 20% of vitamin Bg and about 10% of vitamin Bg and nicotinic acid are lost.
Preservation of vitamins in dairy products. In refrigerators, vitamin A is stored for a long time in butter and cheeses. Rancidity of the oil, which leads to the destruction of vitamin A, can be prevented by the addition of so-called antioxidants, which impart stability to vitamin A. The best of these is vitamin E, found in oil obtained from wheat, soybean and corn germs. Another remedy is to introduce special yeast into the oil.
Preservation of vitamins in berry, fruit and vegetable products. Methods of processing raw materials used in the Soviet canning industry contribute to the preservation of vitamin C. This is achieved by sulphation of fruits and berries, which consists in treating them with sulfur dioxide.
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The usual methods of drying vegetables and berries in the air, in the sun and fire drying in vegetable dryers, oven ovens and on stoves lead to the almost complete destruction of vitamin C and a significant destruction of vitamin A (carotene).
Rose hips (red) are among the few exceptions. They do not contain substances that oxidize vitamin G and are very rich in this vitamin.
Rose hips rich in vitamin C have white and pink petals and orange or red fruits; poor in vitamin C - yellow petals, dark brown or black fruit.
Rosehip selection should be made during the period of incomplete ripening of the fruit. Ripe and overripe fruits are less suitable for processing and storage. Rose hips can be dried in special dryers, a Russian oven or in an oven, and in extreme cases under a canopy or in the attic. The most favorable temperature for drying is 80-100°C.
A sign of the end of drying is the ability of the peel of the fruit to break and break into pieces when squeezed with fingers.
When dried with hot air at 100-120°C for 2-3 hours, green plants retain up to 80% of carotene. In these cases, drying is also carried out until leaves and stems are fragile and easily rubbed between the fingers. After drying, the leaves and stems are ground into powder, sifted through a sieve and placed in a well-sealed dish to avoid moisture.
Pre-sulphurization of fruits (i.e. treatment with sulfur dioxide) or pre-blanching (i.e. boiling raw materials with live steam), used in modern methods high-temperature and short-term drying, ensure the preservation of vitamin C. For example, when drying non-sulphated cabbage, up to 40% of vitamin C is destroyed, and almost all vitamin C is retained in pre-sulphated cabbage. However, with further storage of such products, vitamin C turns out to be unstable and its amount is quite is rapidly declining. Sulfitation destroys vitamin Bi and a significant amount of carotene.
Storage conditions for dried fruits and vegetables are also of great importance. Significantly reduces
loss of vitamins, keeping them in a well-sealed form at a low temperature, in a dry room.
A good way to preserve vitamin C is fermentation. Properly fermented and stored cabbage and tops of various plants serve as a valuable C-vitamin carrier. The brine also contains vitamin C. However, repeated freezing and thawing of sauerkraut destroys vitamin C. In cabbage brine, vitamin C is generally not stable. Therefore, the sauerkraut extracted from the barrel should be eaten as soon as possible. It must be stored in brine, otherwise vitamin C in it is destroyed within a few hours.
Among some peoples in the far north, it is customary to ferment the shoots of the polar willow and bulbous plants and use them as a seasoning during the winter. Salted wild garlic (wild garlic) is very popular in Siberia. She is a good C-vitamin carrier. Common pickles and pickled green tomatoes (tomatoes) are completely devoid of vitamin C.
Preservation of vitamins C and A in canned foods. Food tin cans of domestic production (boiled and fried beef, lamb and minced meat) were introduced into the Russian army as early as 1869. In the Khiva campaign of 1873, the troops were also supplied with such canned food: cabbage soup and porridge, dried sauerkraut, dry cabbage soup, pea soup, meat extract. But these canned goods were not widely used in the country before the Great October Socialist Revolution. Methods for the production of canned food were backward, semi-handicraft.
The Soviet canning industry has made significant progress and mastered new advanced production methods. They allow you to save most of the vitamins C and A (carotene) in canned food. These methods include: 1) improving the quality of fruits and vegetables processed into kochserzy; 2) carrying out breeding work on growing fruits and vegetables with a high content of vitamins; 3) preservation of vitamins in raw materials; 4) changing the mode of sterilization of canned food; 5) coating of cans inside with a special protective varnish.
The Soviet canning industry organized the production of special canned fruits and vegetables with a guaranteed content of vitamins C and A (carotene).
Preservation of vitamins during culinary processing of products. Currently used cooking methods are not always perfect enough and lead to loss of vitamins, especially vitamin C.
Losses of vitamins occur during cleaning, cutting and storage of prepared raw materials. When cleaning, cutting vegetables and storing sliced food, some substances are released that quickly oxidize Vitamin C. Therefore, only the amount of vegetables that is required for the next period of time (no more than 1-1% of an hour) and do not leave them the next day.
When cleaning vegetables and herbs, up to 10% of vitamin C is lost; therefore, it is recommended to clean and grind them only shortly before preparing the corresponding dishes. So, for example, a boiled peeled potato loses 20% of vitamin C after storage for 24 hours, and the same cut potato loses 40% of vitamin C after 10-30 minutes.
Peeled vegetables should not lie in water for a long time, since in this case part of the vitamin C contained in them passes into the water, and part is destroyed.
Sauerkraut is one of the most important foods containing vitamin C. It often loses 30-80% of vitamin C as a result of sorting and thorough washing. To preserve the vitamin C in sauerkraut while sorting, all you need to do is squeeze out the brine and rinse the cabbage quickly in cold water. Cabbage brine is used to add to first courses and to dress vinaigrettes.
Peeled, washed and chopped vegetables are recommended to be scalded with boiling water before immersion in the broth to prevent the action of substances that destroy vitamin C. Vegetables should be dipped into boiling water as soon as possible, since at a high temperature the action of substances that destroy vitamin C ceases. If this is somehow impossible , then the time required
storage of potatoes in water is reduced to 2-3 hours. Beets, carrots and other root vegetables should be stored covered with a damp cloth for no more than 2-3 hours.
When cooking vegetables, put them in boiling water. In this case, the peeled potato loses only about 20% of vitamin C, while when immersed in cold water, up to 40% is lost. Potatoes in their skins placed in hot water lose very little vitamin C, and when placed in cold water lose an average of 25%. Thus, when boiled in their skins, potatoes retain significantly more vitamin C. The best way preserving vitamin C is steaming vegetables. With this cooking method, vitamin C is almost completely preserved in potatoes.
Steaming and other vitamin C-preserving cooking methods are also recommended for frozen vegetables, which cook two to three times faster than unfrozen ones. Frozen potatoes and cabbage almost completely retain vitamin C, since the destruction of vitamin C stops at a low temperature. However, special processing of such vegetables is necessary. In order not to destroy vitamin C in them, they should be stored in the cold, preventing thawing.
Once thawed, the vitamin C in vegetables becomes very unstable and breaks down quickly. This happens especially quickly with repeated freezing and thawing.
Potatoes thawed in air lose up to 35% of vitamin C after 6 hours of storage; shredded cabbage, thawed in air, loses up to 85% of vitamin C after 3 hours.
Boiling should be carried out in pots or pans filled to the top, with a tightly closed lid, bio to avoid the entry of large amounts of air. When cooking in open pots, twice as much vitamin C is lost than when cooking in closed pots. In the pot or pot, the water should cover the vegetables. Boiling should not be violent. Stir the liquid carefully, not letting too much air into the cauldron or pot and keeping a layer of fat on the surface, as it prevents air from entering the vegetables.
Vegetables can also be sautéed for 30-40 minutes in fat in a sealed container. During this time, they are covered with a fatty membrane that protects vitamin C and carotene from oxidation. Potatoes boiled in a soup without a fat layer lose 50-70°/o of vitamin C, while in a soup with a fat layer they lose only 20-40%.
When cooking vegetables, soda should not be added, since the alkaline reaction quickly destroys vitamin C, and, conversely, it is recommended to add a certain amount of food acids: acetic, citric or cabbage pickle.
To preserve vitamin C, the dishes in which food is cooked are also important. Vitamin C is destroyed when cooked in copper or iron, poorly tinned cookware, but is retained when cooked in chrome steel cookware, in aluminum, enameled or well tinned cookware.
According to recent data, vitamin C is much better preserved in thick soups(flour, cereal, potato), rather than in sour borscht.
Preservation of vitamin C in thick soups is apparently associated with the presence of starch in cereals and potatoes. From this point of view, dressing them with flour is of particular importance for the preservation of vitamin C in liquid dishes.
Filling liquid dishes with wheat flour (best up to 3%) increases the retention of vitamin C in vegetables, borscht and vegetable soups by an average of 20%. Soy and buckwheat flour have the same effect.
The introduction of salt in acidic liquid dishes (shchi, borscht) in the amounts accepted in public catering (0.6-1%) also increases the persistence of vitamin C.
The action of substances that preserve vitamin C, to a certain extent, also protects against the harmful effects of dishes in which a liquid dish is prepared (a cauldron with a disturbed half-hearth, a cast-iron cauldron, an iron cauldron, an iron bucket). This is very important for cooking in the field.
In cereal soups made from oatmeal and pearl barley with potatoes, when standing on the stove for two hours at 70 °, up to 80-90% of vitamin C is preserved.
The larger the volume of dishes in which a liquid dish is made, the better it retains vitamin C.
Cooking vegetables should be stopped as soon as they are ready. In this regard, the sequence should be observed when laying vegetables, given that it takes 10 minutes to cook sorrel or spinach, young cabbage, carrots or whole potatoes - 20-30 minutes, cabbage - 30-50 minutes, beets - 1 hour 15 minutes.
The water in which vegetables were boiled should not be drained, but eaten, using it to season nervous dishes and sauces, since a significant amount of vitamin C and other water-soluble vitamins pass into the broth (for example, when boiling cabbage - up to 60% vitamin C).
Thus, with proper cooking of vegetables, one can not only prevent the complete destruction of vitamin C, but also reduce its loss to a minimum.
In the manufacture of mashed potatoes, it retains only 10-30% of vitamin C, and in cutlets, rolls and potato casseroles - no more than 5-10% of this vitamin.
The total duration of cooking and storage of soups, cabbage soup and borscht, etc., with a ready-made decoction of bones, should not exceed 2-3 hours. Long-term storage of ready-made meals both on the stove and in camp kitchens and in thermoses and reheating them is unacceptable. Liquid meals after they are prepared should be stored until distribution for no longer than one hour and at a temperature of 70-75 °, since after 3 hours the content of vitamin C in them drops to 20-30%, and after 6 hours the vitamin C in them is almost completely destroyed (Fig. 20).
Frying is less detrimental to vitamin C than boiling; although the temperature during frying is higher, it requires less time and the action of substances that oxidize the vitamin stops faster. Simmering destroys vitamin C to a much greater extent than boiling.
Culinary processing affects vitamin A and carotene much less than vitamin C. The content of carotene in raw materials prepared for processing is adversely affected by sunlight. Therefore, vegetables should be stored in a dark, cool place.
Potato soup
Rice. 20. Preservation of vitamin C in potato soup and cabbage soup
Loss of carotene when passing through carrots, onion, tomato paste and tomato puree are insignificant, since in this case the vegetables are covered with fat, which protects against oxidation.
Vitamin A and carotene, unlike vitamin C, are destroyed in an acidic environment. Therefore, food acids should be introduced into the appropriate dishes (vinaigrettes, etc.) only before they are released. In all other respects, when processing food products containing vitamin A, the same rules should be followed as when processing products containing vitamin C.
B vitamins are much more stable than vitamin C, and are relatively little destroyed during cooking. Of these, vitamin Bx is the least stable. During cooking, frying and baking, an average of up to 20 ° / o of vitamin B6 is destroyed. If the instructions that contribute to the preservation of vitamin C are followed, the vitamins of group B are also completely preserved.
A properly constructed culinary process retains most of the vitamins found in raw foods, while improperly cooked food can be deprived of vitamin C, and also lose a significant amount of other vitamins.
