A number of tricks for preparing food from raw foods. Distinguish between cold and thermal (thermal) cooking. In the process of cooking, there is an improvement in taste, nutritional value of products, as well as ensuring the safety of food. Therefore, compliance with the rules during cold and heat treatment, maintaining temperature and processing time are very hygienic. value.

Primary processing of meat and meat products.Frozen meat should be thawed at room temperature. Thawing of meat in warm and hot water, near a stove or heating devices, leads to the loss of nutrients and extractives with juice, and to a deterioration in taste. Contaminated areas should be cut off from chilled or thawed meat, then rinsed thoroughly in running water and dried on a wire rack. Then the meat is separated from the bones, tendons are removed, etc. The meat is cut into pieces of different sizes or minced meat is prepared. Butchering meat, cooking semi-finished products should be done on special. boards .. Frozen birds are also thawed in air, at ordinary temperature. The gut is removed from the gutted bird, its head and legs are chopped off, it is scorched if necessary, then it is thoroughly washed in running water and dried. The contents and mucous membrane are removed from the stomach, the gall bladder is removed from the liver; the necks, paws are steamed, skin is removed from them. Sub products (liver, kidneys, heart, etc.) require particularly careful processing due to their lower storage stability. Frozen offal is thawed at room temperature, then cleaned of residual blood, mucus. The liver is freed from films, the gall bladder. After removal of the films, the kidneys are washed several times in cold water to remove specificity. smell. Corned beef is soaked in cold water, changing water several times.

Before cutting, frozen fish should be thawed, sturgeon fish and any fish fillet at normal temperature, the rest of the fish in cold water until completely thawed. It is recommended to add salt to water to reduce the loss of mineral and substances. Thawed fish should not be stored. When cutting hands, tables, knives are contaminated with scales, mucus, therefore, before further processing of fish (cutting into pieces, boning, etc.), you should wash your hands, and when cutting use clean kitchen equipment.

In the initial processing of vegetables  maximum preservation of their vitamin value should be ensured. After thorough washing and cleaning, vegetables do not need to be kept in water for a long time, they are immediately subjected to heat. processing. When cleaning, the potatoes are exempted from the eyes and green places in order to avoid the ingestion of a substance (solanine) that can cause food poisoning. If the cabbage is damaged by worms, it should be for 20-30 minutes. immerse in salt water (25 g of salt per 1 liter of water). Sauerkraut should not be washed, because at the same time most of the vitamins and mineral, salts are lost. Parsley, dill, other herbs, spring onions, sorrel, spinach, salad after the bulk is poured for 30 minutes. cold water to remove the earth. Especially thoroughly wash vegetables, fruits and berries that are not exposed to termich. processing. Dried vegetables are sorted, washed, poured with cold water for 1-2 hours, then boiled in the same water. Dried fruits are sorted and washed 2-3 times with warm water.

During heat treatment, the palatability of food improves, its digestibility increases, and digestion is facilitated. At high temperatures, worm eggs, pathogens of intestinal infections and food poisoning die. Microbial spores under normal heat treatment conditions remain viable. The most reliable m-1 are such methods of heat treatment as cooking, stewing. Lengthening the time of heat treatment leads to a deterioration in the taste of food, the destruction of food and biologically active substances, vitamins.

The time of heat treatment of meat depends on its type, variety and size of the pieces. The meat is subjected to various culinary processing - cooking, frying, stewing. When cooking, juice is released, consisting of water, extractives, mineral, salts. All these substances pass into solution and form a broth. To get a strong broth, the meat is dipped in cold water, gradually brought to a boil and maintain a weak boil until the end of cooking. To get juicy and soft boiled meat, it is dipped in boiling water and cooked on low heat for a shorter time. In boiling water, the meat proteins coagulate and remain in the meat, it turns out to be tender and juicy, more valuable in nutritional terms, and the broth is less saturated. Steaming leads to less loss of extractive, mineral, and other nutrients. The readiness of fried, stewed, cooked meat is determined by piercing it with a fork - in this case, light juice should stand out.

Minced meat and fish, cutlet mass are often contaminated with microorganisms. Therefore, products from minced meat and fish, as well as pieces of fish should be fried on both sides in boiling fat for at least 10 minutes. Fried fish products quickly lose their juiciness and taste, so they should be cooked before use and stored for no more than 30 minutes. When making jelly, the products are cooked until fully cooked (approx. 3-5 hours), after disassembling and grinding, the meat is poured with broth, boiled again, poured into clean, previously scalded with boiling water forms and cooled down after cooling.

In vegetables and fruits with thermal. processing may cause loss of food and biologically active substances. To prevent the destruction of vitamin C, the following rules should be observed: vegetables are placed in boiling water, minimizing the cooking time, avoiding the digestion of vegetables. Do not over-grind vegetables and fruits, but they need to be boiled in a minimum amount of water, in an enameled bowl with a lid closed. Cook vegetable dishes before use, avoiding reheating. Most (up to 95%) of vitamin C is lost when stewing vegetables, preparing mashed potatoes, casseroles. Frozen vegetables, not thawing, dipped in boiling water and cook until tender.

Nutritional supplements

Nutritional supplements - these are natural and synthetic chemical compounds that do not represent a source of energy, like food, are not used in their pure form, but are only added to products to facilitate the process, extend the shelf life or give a certain consistency to the final product.

Recently, in the media and in popular science publications, the term “food additives” is often used also to refer to herbal mixtures, sets of herbs, as well as for biologically active substances.

Anyone, one way or another, consumes nutritional supplements with food. To improve the presentation of products, increase their shelf life and increase market value, preservatives, artificial colors, emulsifiers and other non-food substances are added to them. Most supplements have no nutritional value and, at best, are biologically inert to the body, and at worst they are biologically active and not indifferent to the body. Some types of supplements can cause allergies.

With the correct, scientifically sound use of food additives, subject to all existing standards (including CDK), the terms and conditions of storage of products, the use of undisturbed (undeformed) containers, food additives should be classified as substances of minimal risk. But only subject to the entire specified complex of factors.

In the EU countries, all food additives are collected in a single register, which is called Codex Alimentarius. Compilers of the registry claim that only non-hazardous additives get into it. Meanwhile, Russian legislation is more stringent. In the "Hygienic rules for food safety and nutritional value", which have been in force in the Russian Federation since July 1, 2002, all additives from the EU registry are divided into three categories: harmless, suspicious and prohibited.

In the European registry, each additive received a three-digit or four-digit number and the letter “E” at the beginning. Its presence means that the product (product) is made in Europe.

The three-digit or four-digit number behind the letter E indicates the code of the specific food supplement. For example: E 152 - activated carbon, E 251 - sodium nitrate, etc. The presence of the food supplement should be shown on the product label. The additive may appear as a separate substance or represent a functional class in combination with the number E.

On the labels of various products you can often find "flavorings identical to natural." This ornate formulation hides a complex mixture of aromatic substances - natural and synthetic. Due to the complexity of the composition of these natural and chemically obtained flavors, these flavors are not included in the classification of food additives, and codes with “E” in the name are not assigned to them.

The use of food additives still leaves open the question of their safety. In any case, they should be introduced into food products in a minimal amount. In Russia, the use of food additives is strictly regulated. Any food supplement is checked first at the Joint Expert Committee of the International Agricultural Organization and the World Health Organization, and then at the Institute of Nutrition of the Russian Academy of Medical Sciences.

13. The effect on agricultural chemicals of food products. Chemical substances,widely used at different stages of production of P. p., may be present in the final product in an unchanged or sharply transformed form. Depending on at what stage the chemicals enter P.'s item, they can be divided into three groups. Chemical substances of the first group pass through all the links of the food chain, as they are introduced into the soil, transferred to plants, then to the animal organism, and finally, they enter the human body with food products of animal origin. This group includes nitrogen, phosphorus, potash mineral fertilizers; components of soil erosion control agents, such as phenols; in residual amounts heavy metals, nitrates, sulfates, organic compounds found in wastewater used as fertilizer; toxic metals (e.g. cadmium) that are part of mineral fertilizers. Chemicals of the second group bypass the initial link (soil) and enter the feed as a result of treatment of plants with growth stimulants, for example, chlorocholine chloride, pesticides: with feed into the body of agricultural animals receive chemical preservatives used to preserve feed, and residual amounts of petroleum hydrocarbons used to grow protein feed components. The third group includes chemicals used in raising animals and birds and administered orally or parenterally. These include hormonal and other animal growth stimulants, drugs.

The introduction into the soil of an excessive amount of mineral fertilizers adversely affects P. n., Since, firstly, it often leads to an adverse change in the content of nutrients and, secondly, to the accumulation in products of compounds that have a toxic effect on the human body.

Food packaging provides protection from pollution, damage, makes it possible to eliminate losses, facilitates transportation, storage and sale. The packaging provides for the prevention of the possible direct effects of containers on product items and indirect harmful effects on consumer health.

The main thing in cooking is to maximize the preservation of nutritious and biologically active substances in the initial products. To do this, you need to master the rational methods of cooking products. After all, all food products require preliminary or so-called cold processing - sorting, cleaning, washing, soaking, separating inedible parts and final heat - cooking, frying, stewing, baking and other cooking methods.

The first condition for cooking is strict, strict observance of the rules of sanitation and hygiene. The hostess herself should always be neat, clean, tidy. You should wash your hands, dishes, boards, tools more often, keep the kitchen area clean.

Food must be washed thoroughly.

Potatoes and root vegetables are best brushed. Leafy greens - lettuce, sorrel - first you need to sort out, remove the spoiled, and then rinse with plenty of water.

It is very important to learn how to rationally use products, as well as food waste.

When cooking, you must strive to minimize the loss of nutrients and biologically active substances. If vegetables, for example, are dipped in boiling water, then the loss of vitamins and nutrients is reduced by 3-5 times.

When thawed in large pieces, frozen meat loses less juice than sliced.

Heat treatment products

As a result of heat treatment, new taste and aromatic substances are formed in the products, their digestibility increases. In addition, the food is neutralized, microorganisms die and the harmful substances contained in some products, such as toxin in morels or solanine in potatoes, are destroyed.

Cooking is the most reliable and common way of heat treatment of products. The temperature of the product at the same time reaches 100 ° C.

Products are boiled in a liquid, steamed or allowed to boil, that is, boiled in their own juice or with the addition of a small amount of liquid. To get a concentrated broth, saturated with nutrients and flavors, meat, bones, fish need to be poured with cold water, bring to a boil over high heat and then cook over low heat over a quiet boil.

If you need to get juicy meat, then it is recommended to lower it into boiling salted water, quickly bring to a boil and cook, also at a quiet boil, until tender.

One of the most important requirements of heat treatment is as follows: it should not be longer than necessary, because with prolonged cooking, the products almost completely lose biologically active substances, the value of food is significantly reduced, its taste and aroma deteriorate.

Frying foods

When frying, the product is heated without adding liquid with fat, which protects the product from burning, provides uniform heating, improves the taste of the dish and increases its calorie content.

The main way is to fry the product in a small (5-10% by weight of the product) amount of fat. This method is most acceptable in home cooking. At the same time, the fat is spread on a very hot pan and heated so that it begins to smoke slightly. Slices of meat are dipped in hot fat and fried on both sides. Do not forget that each slice of meat must be immersed in well-heated fat, then the meat will be fried, juicy and tasty.

If the meat is fried under a lid, then it will not brown.

You can fry the product in deep fat, that is, in a large amount of fat, when the fried product is completely immersed in fat. In this way, brushwood, pies, potato chips are prepared. The deep-fried meat is also very tasty.

And here's a tip: put the slices on both sides, browned on both sides, on the paper so that the excess fat is absorbed into it.

Grilling products. Grilling

Grilling literally means burning. This is one of the methods of heat treatment of meat or fish on a spit - skewer or grill - without the use of fat. This processing method is most suitable for young meat, especially lamb and pork.

Meat can be grilled over hot coals, in a hot oven or in an electric grill. Through infrared rays that emit red-hot coals or a red-hot spiral, meat or fish warms up 2-2.5 times faster than when frying in a pan.

On the surface of the product, whether it is meat or fish, a thin crust is formed during grilling, vessels, pores are as if sintered, melt under the influence of heat, so juice does not leak. That is why a product made in this way turns out to be juicy, tasty and non-greasy.

By the way, doctors consider this method to be the most promising, since, among other benefits, the finished product is less caloric.

For roasting in the oven, usually choose large pieces of meat (approximately 1-3.5 kg). Roast the whole bird. Non-greasy meat, before placing it in the oven, smeared with warmed butter, sour cream or vegetable oil, and greasy - sprinkled with water.

Lean meat is first fried in a pan until a golden crust is formed and only after that it is placed in an oven at a temperature of 130-150 ° C.

Fatty meat (goose, ducklings, pork) is placed in an oven heated to 230-240 ° C, and kept until browning, after which it is recommended to lower the temperature.

The duration of the roasting depends on the thickness of the piece and its size. The readiness of the product is determined using a needle or knitting needle: if the meat is not roasted, pinkish juice will stand out from it.

Meat, fish, poultry can be baked in foil. It is best to bake in this way meat and poultry, divided into portions, which could be completely wrapped in foil.

Sprinkle the meat or fish with salt, add spices and seasonings to taste, then wrap so that the juice does not leak out and bake at a temperature of 170-180 ° C for about 20-30 minutes until cooked.

If you bake boiled, fried or in any other way cooked meat, fish or mushrooms, then you will get a dish with a very special taste.

So, in a refractory form or in a frying pan you need to put pieces of the product, season it with spices and seasonings, pour sauce or wrap it with a layer of dough (yeast or puff) and bake in a hot oven until golden brown.

Food Extinguishing

Products that are not softened sufficiently when frying, such as game, old poultry, kidneys, heart, are usually stewed.

Stewing is a combined method of heat treatment: first, the product is fried, and then boiled in gooseberries or any other deep dishes, adding seasonings and sauce.

In a pan in which you fried the meat, you need to pour a little water or broth, boil for 2-3 minutes. Pour the product with the resulting juice, adding sautéed roots, tomato paste, spices and simmer under the lid over low heat or in the oven until cooked.

You can stew the product on the stove or in the oven, using instead of water a fat broth - brez. This method is called brezerevanie.

The primary processing tasks of the products are:

1) thawing frozen products;

2) the release of products from pollution and inedible parts;

3) removal from the products of parts with reduced nutritional value;

4) giving the product the size, shape and condition corresponding to the type of culinary product for the manufacture of which the product is intended;

5) the application of effects that accelerate the subsequent heat treatment of the product.

Thawed frozen animal products - meat, offal, poultry, fish.

In order to get rid of contaminants, most animal and plant foods that enter the primary processing are washed. When washing, not only visible impurities are removed, but also the bacterial contamination of products is significantly reduced. To achieve a more effective disinfection, washing the product is repeated at various stages of its primary processing.

Plant products are freed from inedible parts by sorting, sifting, cleaning and stripping. When sorting vegetables, mushrooms, cereals and legumes, foreign impurities, spoiled, unfit food items, etc. are manually removed from them. Sifting out various impurities from loose products - flour, cereals. When peeling vegetables, remove the skin. Stripping consists of cutting out spoiled and other parts of the food that are not fit for food.

The techniques by which animal products are freed from inedible parts include:

1) plucking removal of feathers from poultry carcasses;

2) singeing - burning of small hairs on the surface of carcasses of birds, heads and legs of large and small cattle;

3) gutting - removal of entrails from carcasses of poultry and fish;

4) stripping - cutting films, tendons, cutting marks during meat processing;

5) soaking corned beef, salted fish.

Examples of methods for removing parts with reduced nutritional value from products include:

1) deboning - the allocation of bones from the carcasses of large and small cattle;

2) cleaning the scales from the fish;

3) removing the fillet from the fish; this removes the spine with the head and tail.

To perform the fourth primary processing task, the following techniques are used:

1) cutting the product into pieces of various sizes and shapes;

2) beating off pieces of meat to even out their thickness to smooth the surface and give it an appropriate shape;

3) grinding into the native structureless mass of meat of slaughtered animals, poultry and fish;

4) mixing chopped meat with water, bread and seasonings to obtain a cutlet mass, mixing flour with various products to obtain a dough;

5) molding products from cutlet mass, dough;

6) breading, i.e. covering the surface of products (mainly from meat, poultry and fish) with flour and ground crackers:

7) stuffing. Primary processing techniques such as soaking legumes (peas, beans, lentils), crushing bones of cattle, as well as small cattle, beating portions of meat to loosen connective tissue, smoothing the thickness with pieces of the like, provide acceleration, subsequent heat treatment product.

Heat treatment

Most foods are unacceptable for eating raw. Therefore, they have to be heat treated. As a result of this, they acquire a pleasant taste and smell, their appearance improves. Many products become softer after heat treatment. Heat treatment improves the digestibility of plant foods.

Heat treatment, in addition, neutralizes the products, since the microorganisms located on them die under the influence of high temperature. However, it should be noted that under normal conditions and temperature conditions of heat treatment, complete neutralization is achieved only if the products are completely benign and not very seeded with bacteria. Therefore, at all stages of the primary processing, it is necessary to strictly comply with sanitary and hygienic requirements, so that by the time of the heat treatment the seed contamination of the product is minimal.

All methods of heat treatment used in culinary practice can be reduced to two main ones - cooking and frying.

During cooking, the products are heated in water, broth, milk or in an atmosphere of saturated water vapor. The temperature of the liquid and product during cooking in conventional food-cooking boilers and cookware does not exceed 100 °.

In hermetically sealed cooking appliances, autoclaves, you can cook products at a temperature of 120-130 °. The use of high temperatures greatly accelerates the cooking process.

The ratio between the amount of product and the amount of liquid during cooking is different. Cooking with a small amount of liquid, when the liquid does not completely cover the product, is called overspray. Appetizing with spices and seasonings is called stewing.

Stew and stew food in a sealed container.

When steaming, the product is placed in wire mesh baskets or boxes in a water kettle so that the water does not come into contact with the product. The boiler is closed with a lid and the water in it is boiled; the resulting steam boils the product. For steam cooking, special steam cabinets are also used, into which steam is supplied through pipes from the boiler room or is obtained in the cabinet itself in a special, evaporation box.

When frying, foods are heated without the addition of liquid (water, broth, milk), but with more or less fat.

Under the influence of high temperature, moisture from the surface of the product quickly evaporates, resulting in a dry crust on it. An increase in the temperature of the crust above 100 °, to about 130 °, causes the decomposition of its organic substances. The resulting chemical compounds have a pleasant taste and smell. With a further increase in the temperature of the crust, chemical compounds with taste and smell are formed.

In culinary practice, several types of frying are used, differing from one another in the way of heat transfer to the fried product.

1. Frying with a small amount of fat: a) on an open surface, b) in a frying pan

2. Frying in a large amount of fat (deep fat).

3. Frying under the influence of radiant heat.

In all methods of frying, fat should not be heated above 180 ° to avoid its decomposition, accompanied by the formation of gaseous products with an unpleasant odor.

The temperature at which fat begins to decompose depends not only on its type, but also on other factors, in particular on the surface of the pan. When heated in a pan with a diameter of 10 cm, the cow’s oil begins to decompose (chad) at 208 °, lard at 221 °, cottonseed oil at 233 °, hydro fat at 230 °, and the fat at 210 °.

Fry with a little fat. The product is heated on a stove in an open shallow dish - a pan, a baking sheet. At the bottom of the dishes put fat (5-10% by weight of the product) and, after it is heated to a temperature of 150-160 °, place the fried product. The fat forms a thin layer between the bottom of the dishes and the product and, due to poor thermal conductivity, slows down the temperature rise of the product. Therefore, before the product starts to burn, a normal crust forms on it on the side that directly contacts the bottom of the dishes. To form a crust over the entire surface, the product must be turned over.

In the oven, the product is fried immediately from all sides. Its surface, not in contact with the bottom of the dishes, is fried due to the heat that is radiated by the heated cabinet walls and delivered by convection currents of air. This technique, when applied to cereals and vegetables, is called baking or baking.

Frying in a lot of fat.  In this frying method, the product is completely immersed in fat heated to 160-180 °. Hot fat, enveloping the product, creates good heat transfer conditions and ensures uniform crust formation on the entire surface of the product.

The ratio between the weighted amounts of fat and the product immersed in it should be at least 4: 1, otherwise the fat cools, which significantly worsens the frying conditions.

For frying in a large amount of fat, use cookware or special devices with fire or electric heating (deep fryers). Dishes should be tinned (steel or cast iron), since the heat deteriorates due to high temperature.

Fill the dishes with fat should be more than half, because when laying food, hot fat foams greatly due to the rapid evaporation of water from them.

Products are immersed in fat directly or in a mesh basket. In the first case, the fried products are removed: slotted spoon and to drain excess fat is placed on a metal sieve.

After 4-5 roasting, the fat is filtered, otherwise it acquires a dark color and a bitter taste due to decomposition of particles trapped in the fat from products from the action of high temperature. Filtered fat can be used for further frying.

Sometimes fried foods are dipped in fat half or one third.

Frying under the influence of radiant heat. When frying under the influence of radiant heat, products are placed on a wire rack or put on a skewer (metal bar, skewer) and placed over burning charcoal - birch, alder or oak. To control the heating, the distance between the product and the coals is changed.

The grate is first heated to 200 °, then wiped, greased with bacon and lay on it the fried product.

The source of radiant heat can serve as electric coils, which are mounted in the upper part of special cabinets - electric grills.

Processes that occur during the heat treatment of products

Meat and fish. The heat treatment of meat and fish causes a decrease in their weight, called boiling or frying. Cooking meat reaches 40%, cooking - 37%. In fish, the infusion and frying constitute 18-20%.

The weight of meat and fish during heat treatment decreases as a result of the loss of water and soluble substances. The bulk of the water in raw meat and fish is held by proteins in a highly swollen state. When heated, the swollen proteins coagulate and secrete (extrude) a part of the water with extractive substances, salts and proteins dissolved in it.

Proteins coagulate gradually as the product warms up. The higher the final temperature, the denser the proteins coagulate and the more meat and fish lose water and soluble substances.

Loss of soluble substances during cooking more than when frying. This is usually explained by the fact that the crust formed on the product (meat, fish) prevents the release of juice from it.

This explanation is incorrect, since the crust formed on the product cannot retain juice.

The true reason for the difference between the amounts of soluble substances released from meat and fish during cooking and frying is as follows.

During cooking, the water released by meat and fish enters the environment in a liquid state, taking with it the dissolved substances from the product. During frying, only a small part of the water is released in a liquid state, while the bulk of it evaporates, so the substances dissolved in it remain in the product.

In addition to the soluble substances released with water, pieces of meat and fish lose fat, melting from the action of high temperature.

The amount of substances (not including fat) extracted from meat during cooking ranges from 1.5-3% of the weight of meat, depending on the type and variety, as well as the method of cooking and the size of the pieces of meat. On average, it is 2; 2%, of which 0.1% is accounted for by the soluble proteins that make up the foam.

There are two ways to cook meat. One is used to get the broth, the other - for the preparation of second courses. In the first case, the water in which the meat is cooked is continuously maintained in a state of weak boiling. In the second case, as soon as the water boils after immersing the meat in it, the heating is weakened and the meat is boiled without boiling at a temperature of 85-90 °.

In the second cooking method, due to the lower temperature, the meat proteins, coagulating, form tender clots that retain more moisture than the first method. As a result, meat cooked in the second way loses less water, and consequently, soluble substances; it turns out more juicy and tasty. However, at a lower temperature, you can only cook more or less tender meat that contains an adhesive substance that is not very resistant to hot water (see below), for example veal. Of beef carcasses, only the upper and inner parts of the hind leg are suitable for cooking at low temperatures.

Regardless of whether the meat for cooking is immersed in hot or cold water, the amount of substances extracted from the meat does not noticeably change.

Fish of various breeds, during appetite in portions, lose soluble substances on average about 1.5% of their weight.

Along with weight reduction during heat treatment, the consistency of meat and fish changes. Raw products, when pierced with a needle, have a marked resistance. In products brought to the readiness by heat treatment, the needle enters freely. Finished products are easy to cut and chew.

The change in consistency is the result of the gluing substance that is part of the connective tissue fibers of meat and fish into glue. The resulting glue is soluble in hot water and, together with other substances, partially passes into the broth.

The conversion of the adhesive to glue begins when the temperature of the product reaches 60 °. With increasing temperature, the process noticeably accelerates. At temperatures above 100 ° glue is formed especially quickly. This is the basis for the use of autoclaves to accelerate the cooking of meat. Under normal conditions, pieces of beef meat weighing about 2 kg are boiled for 2-2.5 hours, in an autoclave at a pressure of 1 atm (temperature 119 °), their cooking continues for 30-40 minutes.

The conversion of the adhesive to glue can be accelerated by the addition of acid. In culinary practice, this is used, for example, in the manufacture of dishes from meat of wild animals, keeping it before frying in vinegar marinade.

The fish gluing agent passes into the glue more easily than the meat gluing agent; therefore, the heat treatment of fish requires significantly less time. The fact that beef is cooked longer than meat of small cattle, poultry and game is explained by the greater stability of the adhesive substance of beef.

The difference in the properties of the adhesive substance causes the meat of old animals to be cooked much longer than the meat of young animals.

Parts of the same beef carcass due to the different stability of the adhesive substance contained in them have different culinary properties; It is recommended to apply different methods of heat treatment to different parts.

For frying, only tenderloin, dorsal and lumbar parts can be used, since their adhesive substance has the ability to quickly turn into glue when heated without adding water.

You can also fry the upper and inner parts of the hind leg from the carcasses not lower than average fatness. Before frying, these parts should be cut into batch pieces, which must be beaten off to loosen the connective tissue.

Other parts of the carcass cannot be fried, because the adhesive passes into the glue so slowly that when heated without adding water, they dry out before the glue can form. Therefore, all parts of beef carcass, except for the above, can only be stewed or cooked.

In various parts of the carcasses of small livestock there are no such drastic differences in the properties of the adhesive substance as in beef carcasses. Almost any part of lamb, pork and veal carcass can be used for frying.

Heat treatment causes a discoloration of the meat. Although slaughter of animals is accompanied by bleeding of carcasses, a small amount of blood still remains in them. However, it is not she who causes the characteristic red color of the meat. In muscle tissue there is the same coloring matter as in blood. At a temperature of 70-75 ° it is destroyed, as a result of which the meat becomes gray.

Meat bones and fish waste.  The bones obtained by processing meat carcasses, as well as the heads, tails, fins and bones obtained by cutting fish, are used for cooking broths.

Raw beef bones contain an average of 50% water, 12% nitrogenous substances, 15% fat, 22% minerals and 1% other substances.

Compared to meat bones, fish waste contains more water and less fat of mineral substances.

During cooking, bones and fish waste are transferred to the broth mainly by glue formed from a nitrogenous adhesive and fat melted by high temperature. Mineral substances of bones are almost insoluble in water, therefore, during cooking, they are released in negligible amounts.

The composition of meat and fish broths obtained from cooking meat, bones and fish waste depends on the ratio between the amounts of water and product taken for cooking, and the degree of boiling. The following is the dry matter content of 1 liter of fat-free, by carefully removing surface fat, meat, bone fish broths obtained from 1 kg of the corresponding product.

The table shows that the meat broth in composition differs sharply from bone and broth from fish waste. The latter, on the contrary, are very close to each other. Extractive substances make up the bulk of the dry residue in meat broth, and glue in bone broth and fish waste broth.

The meat broth due to the presence of extractives in it has a specific meat taste and smell; this broth is a powerful sokogonnym means

stimulating the activity of the digestive system.

Bone and fish stock broths as sokogonny funds are of little importance. Glue gives them a distinguishing feature from vegetable broths.

Plant products. In its raw form, most vegetables, cereals and legumes are characterized by significant rigidity, which is due to two reasons:

1) a strong connection between the cells that make up the plant tissue that forms these products;

2) the stiffness of the cell walls. During the cooking process, hot water partially transforms into a soluble state a substance that sticks together individual cells, as well as part of the substances that make up the cell walls. As a result of this, the bonds between the cells are weakened and the cell walls are loosened. Therefore, during cooking, vegetables, cereals and legumes lose their rigidity, which is characteristic of them in their raw form and soften.

The speed of digestion of plant products depends on the resistance to the action of hot water of a substance that glues glue on a point of plant tissue. This resistance depends on the nature of the various products. So, for example, potatoes are cooked for 25-30 minutes, millet - 40 minutes, beans 1-1.5 hours.

Even between different varieties of the same product, there is a very big difference in this regard. Especially often it is observed in peas. So, some varieties of peas are boiled in 45 minutes, others in 1.5 hours, and others in 2-2.5 hours.

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1. Thermal Food Processing Methods

The heating . Thermal processing of products is the main way of the technological process of production of culinary products. Heating the product using various heat transfer media causes changes in its structural-mechanical, physico-chemical and organoleptic properties, which together determine the readiness, texture, color, smell and taste of the product.

Heat treatment of products is carried out in various ways: immersion in a liquid medium, treatment with steam-air and steam-water mixtures, hot steam, heating in the field of microwave currents, infrared radiation, contact heating.

All methods of heating food can be divided into two groups: surface and volume heating. The most common surface heating

Surface heating . In this case, the surface of the product is heated by contact with water, steam, heated grease, air or infrared rays.

From a heated surface, heat is transferred due to thermal conductivity deep into the product, and its entire mass gradually warms up. This type of heating can be contact or radiation. Upon contact heating, the product is placed on heated surfaces or in a heating medium (water, steam, grease, heated air).

In this case, the product is heated only on one side and must be turned over during processing. With radiation heating, the product is irradiated with a stream. infrared rays (ICL), and it warms up simultaneously from all sides.

Source ICL  there can be heated surfaces (walls of ovens, electric heating elements, etc.) or special lamps (tubular or conical with a mirror surface).

ICL  penetrate into the product to a depth of 1-2 mm, and in this thin layer their energy is converted into heat. Therefore, the surface of the product heats up very quickly and a dehydrated crust forms, in which the temperature quickly reaches 130-150 ° С.

This heating method is used in grill machines and barbecue stoves. In practice, several heating methods are often used simultaneously.

For example, if the product is not completely immersed in a liquid, then the lower part of it is heated by water, and the upper - by steam. With all methods of surface heating, a temperature difference is created (temperature gradient) between the surface and the internal parts of the product. The temperature difference causes moisture to move from the surface to the center of the product (thermal diffusion).

Phenomenon this is called t thermomass transfer  or thermal moisture transfer. It contributes to the rapid formation of a crust on the surface and a decrease in moisture evaporation during frying, as well as a decrease in the intensity of diffusion processes during cooking.

Volumetric heating . With volumetric heating, the energy of electromagnetic waves or electric current is converted into thermal energy in the product itself and almost all of its mass is heated almost simultaneously. culinary caramelization semi-finished product

There are two methods of volumetric heating: electrical contact and microwave (microwave heating). In the electric contact method, an electric current is passed through the product. In accordance with the Joule-Lenz law, heat is released when a current passes through a conductor. However, in this case, electrolysis (decomposition) of electrolytes contained in its liquid phase (salts, acids, etc.) occurs in the product.

Therefore, this method is used quite rarely. When microwave heating, the product is placed in an alternating electromagnetic field. All products contain dipole molecules, or particles, in which the available electric charges are spatially separated.

For example, in a water molecule, one end is positively charged (hydrogen ion) and the other negatively charged (hydroxyl ion). In addition, even neutral molecules in an electromagnetic field can become dipoles.

This is explained by the fact that the charges symmetrically located in them can be shifted under the action of external fields - secondary polarization. If the dipole particle is placed in an electromagnetic field, then it will turn so as to be located along the lines of force.

If the direction of these lines is changed, then the particle will change its orientation. In an alternating electromagnetic field, the direction of the magnetic lines of force changes several thousand times per second, so the dipoles begin to oscillate, the kinetic energy of the movement of the molecules is released, and the product quickly heats up.

The penetration depth of electromagnetic waves into the product depends on their frequency and the properties of the product (its dielectric characteristics).

When using microwave heating, the heat treatment time is reduced, the energy consumption is reduced, the loss of mass and soluble substances is reduced, proteins are less denatured and unsaturated fatty acids are oxidized.

Changes that occur in this case with food substances, their effect on the human body is still not well understood. Microwave heating is recommended to be used mainly for heating chilled and frozen foods, for thawing frozen foods.

With volumetric heating, there is no temperature difference inside the product, therefore, thermal mass transfer does not occur and therefore a crust does not form, microwave heating can be compared to cooking in one's own juice - letting down.

Cooling- heat transfer to the environment. Products can be chilled under both natural and artificial conditions.

So, in order to maintain the quality of the products (primarily perishable ones) received at public catering establishments, a lower storage temperature is required at which the development of microorganisms is suppressed and unwanted biochemical processes that occur in the products themselves are slowed down.

Cooling is also used to create the modes necessary for carrying out technological processes: gelation, rolling puff pastry, whipping foam, etc.

In addition, cooling is used in the centralized production of culinary products (chilled dishes) in order to extend the time for its implementation.

Heat treatment value . Heat treatment of products, as a rule, is the final step in the preparation of culinary products.

In some cases, heat treatment precedes mechanical processing (cutting, cleaning, wiping, etc.) or plays an auxiliary role in primary processing  raw materials and products (scalding vegetables to protect them from darkening, or sturgeon fish in order to facilitate their processing, etc.).

In the process of heat treatment, the digestibility of culinary products increases, makes it tasty and aromatic, its disinfection occurs.

Digestibility of products, heat treated, due to a decrease in its mechanical strength, while the products soften, easier to chew and wet with digestive juices, increases the digestibility of food.

The decrease in the mechanical strength of animal products is caused mainly by a change in proteins when heated - they denature and are easier to digest. Starch turns into a paste and is easier to digest.

New are formed flavoring and aromatic substancesthat stimulate appetite, and therefore increase the digestibility of food. The activity of antioxidants contained in some raw foods that inhibit digestion is lost.

When the products are heated, the microorganisms that form the spores become inactive and are not able to multiply.

Most non-spore bacteria die. Bacterial toxins are destroyed. Poisonous substances contained in some raw foods (mushrooms, eggplant, colored beans) are destroyed or converted into a decoction.

Heat treatment also has its drawbacks. Thus, prolonged and excessive heating of fats causes a number of undesirable changes in them (oxidation, polymerization, hydrolysis and deep decomposition).

There is a loss of a part of soluble and volatile aromatic as well as flavoring substances, a change in the natural color of products, and destruction vitamins  and other biologically active substances.

Proper organization of the technological process, knowledge of the reasons that worsen the quality of products, and the skillful use of rational culinary techniques will minimize the loss of nutrients and prepare high-quality culinary products.

2. Technological characteristics of vegetables, fruits and mushrooms. The technological process of mechanical culinary processing of vegetables

At catering enterprises, vegetables of various groups are used to prepare dishes, side dishes, culinary products. They arrive most often in a fresh and processed form. The culinary use of vegetables is determined by their technological properties: composition and content of nutrients, structural features of the tissues.

So, for cooking use table varieties of potatoes with an average starch content of 12-16%.

Their technological properties are determined by: the shape of the tubers, the number and depth of the eyes, the degree of darkening of the pulp of raw and boiled potatoes, the preservation of the shape during heat treatment, the consistency of boiled potatoes, as well as taste.

The best for the production of semi-finished products is round or oval-round potato with a small number of eyes and a size of at least 5 cm in smallest diameter.

It is advisable to use tubers with crumbly flesh of white or cream color for making mashed potatoes, mashed potato products, mashed soups. Tubers with thick or watery pulp are used for dressing soups, side dishes from boiled potatoes and for frying.

The best technological properties are characterized by carrot varieties with bright orange pulp, a small core and a smooth smooth surface.

It is better to take beets for culinary use with dark-colored pulp, without pronounced light rings. Pale coloration and ringing are signs of a relatively rough consistency and unsatisfactory taste.

When cooking borsch, dark-colored beets are stewed raw, and slightly colored, first boiled whole in a peel. The culinary use of white cabbage depends on its degree of maturity, size and density of heads of cabbage.

It is advisable to use early cabbage in raw form for salads, for seasoning in large slices, as well as for cooking soups. Salads, soups, minced cabbage, cabbage cutlet mass are prepared from dense heads of medium- or late-ripe cabbage; from loose - cabbage rolls and schnitzels. Red cabbage is used mainly for salads and stews.

Brussels sprouts - for cooking soups, boiling and baking.

Salads are prepared from kohlrabi, it is let in and stewed. Cauliflower heads are dense and loose. Varieties with a dense, snowy-white large head are considered the best for culinary use. The loose heads of cauliflower are suitable for soups, dense - for second courses.

The use of onions depends on the severity of its taste. Passed onions in seasoned form - seasoning for soups, fried meat and fish dishes; onions of mild and sweet varieties are added to salads and fresh vinaigrettes, as well as passer.

Vegetables (as well as fruits) are biological systems in which metabolic processes, such as respiration, hydrolytic and oxidative processes, continue during storage. They consist of tissues: integumentary, parenchymal, conductive. The edible part of vegetables is represented mainly by parenchymal tissue.

Couplenchemnwoven fabric consists of thin-walled cells that grow evenly in all directions. The contents of individual cells is a semi-liquid mass - the cytoplasm, into which various cellular elements are immersed: vacuoles, nuclei, plastids, etc. (Fig. I.1). Between themselves, the cells of the parenchymal tissue are connected by interlayers of the middle plates, which give the vegetables mechanical strength.

The ratio and structure of certain types of vegetable tissues depend on their age and determine the method of culinary use, the amount of waste during mechanical processing,

Thus, the waste in the purification of young potatoes having a thin integumentary tissue is 20--25%, and in the processing of mature it reaches 40%. Young zucchini (11--12 days old) can be used whole without cleansing, and mature (more than 14 days) have to remove the skin, seeds and seed pulp (conductive tissue).

The properties of the finished product largely depend on the quality of vegetables entering the enterprises. Quality indicators of raw materials, which are standardized by standards, are the shape, size, color, maturity, internal structure of vegetables and fruits, the presence of mechanical damage, agricultural pests, diseases, acceptable levels of "pollutants" (nitrates, pesticides, etc.).

Technological mechanical process processing of vegetables . It consists of the following operations: acceptance, short-term storage, sorting, washing, cleaning, rinsing and slicing.

At acceptance check the lot weight and the compliance of vegetables with the requirements of the standards. For this, vegetables are weighed and the results obtained are verified with the data indicated in the accompanying documents. The quality of vegetables is determined organoleptically: by color, smell, taste and texture. The quality and safety of the finished product, the amount of waste, and the processing method depend on the quality of vegetables.

To store the operational stock of vegetables necessary for the smooth operation of the enterprise, special vegetable pantries are used in which they maintain the necessary temperature, humidity and provide a multiplicity of air exchange. These pantries are equipped with bins, shelving, and merchants.

At sorting remove rotten, beaten or sprouted specimens, impurities, and also distribute vegetables according to size, degree of maturity and their suitability for the preparation of certain dishes and culinary products. Most vegetables are sorted by hand. In large enterprises, machines are used for sorting, sizing according to the size of potatoes.

goal car wash - removal of land and other contaminants, reduction of contamination by microorganisms. The sink has not only sanitary significance, but also lengthens the life of vegetable cleaning machines, facilitates the disposal of waste. Wash vegetables in vegetable washing machines or manually.

At clean up vegetables are removed parts with reduced nutritional value (peel, peduncle, coarse seeds, etc.) in vegetable cleaning machines or manually. The peeled vegetables are rinsed and chopped.

goal slicing - giving vegetables the necessary shape and size.

Potato processing. Washed and calibrated potatoes are peeled in batch or continuous potato peelers. Large tubers peel faster, and while small tubers are peeled, a large layer of pulp is removed from them, so it is important to sort the potatoes first.

Sometimes, after cleaning large tubers, the machine is unloaded, peeled specimens are taken, and the rest are again cleaned. The costs of labor and time for cleaning are fully offset by the fact that the cleaning time is reduced, and the amount of waste is significantly reduced.

To reduce waste, the rules for the operation of potato peelers should be observed: regulate the water supply, monitor the condition of the grater surface, prevent excessive cleaning, and do not load more potatoes at the same time than is established for machines of this type. Pre-soaking dried potatoes helps reduce waste.

The nutrients in the potato tuber are unevenly distributed: protein is most found in the peripheral and central parts of the tuber, starch in the zone of vascular bundles under the bark, and mineral substances in the peripheral parts. Therefore, the thicker the tuber layer removed during cleaning, the greater the loss of nutrients.

Waste during washing and sorting of mature potatoes is 5--6%, with mechanical cleaning - 10--20%, with cleaning - 11--15, and only 25--40% depending on the season. Waste quickly deteriorates, so it must be removed from the workshop or recycled in a timely manner. In the processing of waste get starch.

Peeled potatoes in the air quickly darkens. Enzymatic processes cause darkening - the oxidation of phenolic substances (tyrosine, etc.) contained in potato cells with the formation of dark-colored compounds called melanins. To prevent darkening, peeled potatoes are stored in water. However, long-term storage in water leads to significant loss of nutrients. So, after 6 hours of storage in the water with whole tubers, the potato loses 0.72%, and chopped - up to 2.5% of all the dry substances contained in it. Therefore, in the centralized production of peeled potatoes, more effective methods of preserving the color of its tubers are used.

Peeled potatoes are used whole or chopped. Not only the appearance of dishes, but often their taste, depends on the shape of the cut. This is explained by the fact that semi-finished products of various shapes have a different specific surface, which affects the loss of water during frying and the formation of new flavoring substances in the surface crust. For example, 100 g of potatoes with whole tubers have a surface of 30-50 cm 2, and chopped straws - about 200-300 cm 2.

The shape of the sliced \u200b\u200bvegetables must match the shape of the products that make up the dish.

Root crop processing. This group of vegetables includes carrots, beets, swede, radish and so-called white roots - parsley, celery, parsnip.

Root crops are sorted by size, removing rotten specimens. Young carrots and beets cut the tops. Beet tops are suitable for cooking borsch and beetroot. Root crops are washed manually or in washing machines, cleaned and washed again. Beets, turnips, swede sweets of small and medium sizes, short carrots are peeled in potato peelers, and long carrots are manually peeled.

The white roots are sorted, then the greens and small roots are cut, then washed and cleaned by hand. The greens are sorted, spoiled, yellowed, sluggish leaves are removed and washed. Purified aromatic roots, thoroughly washed, are used to flavor broths.

In red radish, the tops and thin part of the root crop are cut; white radish is also peeled.

Store peeled root vegetables on baking sheets or trays covered with a damp cloth.

To prepare meals, root crops are cut into pieces of various shapes. In the table. A.2 and fig. Section 2 shows the most common forms of slicing root crops.

Horseradish treatment. Horseradish is peeled and washed. If the root is slightly faded, it is pre-soaked in water.

Processing cabbage vegetables. Cabbage vegetables include white-headed, red-headed, Savoy, leaf (salad), cauliflower, Brussels sprouts, kohlrabi, Chinese, Beijing, broccoli.

White-headed, Red-headed, Savoy Cabbage treated the same way: they clean the upper leaves, washed, cut the head of cabbage into four parts and cut out the stump. To prepare cabbage rolls, the stump is removed without cutting the head of cabbage. Kocherig contain more vitamin C and carbohydrates more than leaves, so they should be used in the preparation of salads. After cleaning, the cabbage is cut into slices for cooking and steaming; straws - for soups, salads, cabbage cutlets, stews; squares (checkers) - for soups, stews; for the preparation of minced meat, it is finely chopped manually with the help of choppers or on cutters.

Leaf cabbage depending on the variety has a different shape and color of leaves. It can be used instead of white cabbage for the preparation of soups, vegetable dishes, salads. When processing from the leaves, thickenings are cut off, washed in running water and dried.

Chinese cabbage - leaf lettuce. They use it fresh for salads, appetizers, decoration of dishes, as well as for cooking boiled cabbage. Prepare as a sheet.

At peking cabbage (variety - Khibiny cabbage) the lower leaves are collected in a dense rosette (diameter 30-50 cm) or loose head. From it you can cook salads, soups, vegetable dishes. Prepare in the same way as leafy cabbage.

Cauliflower. Before use with cauliflower, cut the leg together with green leaves 1 cm below the branch of the head of cabbage. The darkened or decayed places of the head are cut with a knife or scraped off with a grater. The peeled heads are washed. If the cabbage is damaged by caterpillars, it is put into cold salted water (40-50 g of salt per 1 liter of water) for 15-20 minutes, and then washed.

A variety of cauliflower is broccoli (or asparagus). The fleshy head (modified inflorescence) of broccoli breaks up into several panicles of fleshy branches with small heads twisted on tops from underdeveloped flower buds. Inflorescences and tender stems are used for food. They are washed with cold water and boiled in boiling salted water for 8-10 minutes.

Brussels sprouts. Use Brussels sprouts in raw form for salads, as well as for the preparation of soups, vegetable dishes. The cabbage heads are not cut too short from the stem so that their shape is preserved during heat treatment, and then spoiled leaves are removed and washed.

Kohlrabi sorted, peeled manually and washed. Cut into strips, slices, cubes. Recommended for the preparation of salads, soups.

Processing onion vegetables. The onions are cut off the bottom, neck, dry flakes are removed, washed in cold water. In large enterprises, special cabinets with an extractor hood are installed for cleaning onions to remove essential oils.

Before heat treatment, peeled onions are cut into rings, half rings, slices or small crumbs. Small onions seedling onions and scallions after cleaning, they are used as a whole for the preparation of some sauces (Russian, sailor), stews and deep-frying.

Leek they sort out, cut the roots, remove the yellowed and decayed leaves, cut off the white part (onion), cut it lengthwise, washed and chopped. The green parts are used as part of a “bouquet of spices” for flavoring broths.

Processing pumpkin vegetables. Pumpkin used mainly for the preparation of vegetable dishes (stewed, fried, etc.). Before cooking, the fruits are washed, the stalk is cut, cut into several parts, seeds are removed, the skin is peeled, washed and cut into cubes or slices.

For cooking dishes from zucchini zelentsy is the most suitable - a young ovary of zucchini of 7-12 days of age, weighing 300-700 g, length up to 25 cm and diameter up to 10 cm. They are washed, cut the stalk and cut into circles. Peel off the mature squash and then remove the seeds. In zucchini intended for stuffing, after cleaning, cut off the top of the fetus, cut them across into several parts and remove the inner part with seeds.

Squash processed and used as zucchini.

Cucumbers sorted by size, washed. Large peppers are peeled, gherkins and medium-sized peppers are not peeled, but cut off the tops and base of the fruits. Cut them into slices, slices, small cubes, and straws. Used for the preparation of salads, cold soups.

Tomato Processing . Tomatoes sorted by maturity and size, removing wrinkled or damaged specimens. Then cut the stem and washed. For fruits intended for stuffing, cut off the upper part with the peduncle, take out the seeds with part of the pulp, drain the juice, sprinkle with salt, pepper and fill with minced meat. Tomatoes are used raw for salads or fried (for side dishes), stuffed and baked.

Eggplant sorted, cut the stalk, washed. Old specimens are scalded and cleaned. Cut into circles, slices or cubes. Processed fruits intended for stuffing are cut lengthwise into halves or across into cylinders, small eggplants can be stuffed whole, the pulp is taken out with the seeds and stuffed with minced meat.

Raw eggplant is practically not consumed due to bitterness, which increases as they ripen. Bitterness is given to the fruit by the substance solanine contained in them. Eggplant fried and baked (stuffed).

Chilli pepper (spicy and sweet) sorted, washed, cut in half, removed the seeds along with the pulp and washed. Cut into strips for salads and soups, in small cubes - for soups. For stuffing, the fruits of sweet pepper are washed, an annular incision is made around the stem and removed together with the seeds, without violating the integrity of the pod, washed again, put into boiling water for 1-2 minutes (blanched), removed, cooled and filled with minced meat.

Sweet pepper is used for salads, vegetable dishes (for example, stuffed peppers).

Processing salad, spinach vegetables and spicy herbs. They are widely used in raw form for the preparation of cold appetizers, salads, when serving soups, main dishes.

Salad, spinach, sorrel, green onion, spicy greens sorting, removing the roots, if any, coarse stems, spoiled leaves and well washed several times in a large amount of cold water, and then under running water and dried on wire racks for 20 minutes.

During storage, the greens quickly fade and the vitamin C content in it decreases. For three days of storage at room temperature, 17-20% of vitamin C is lost, and when stored in refrigerators (3 ° C) - 6-8%. Vitamin C is destroyed especially quickly in shredded greens, so a small amount of it should be cut as it is sold.

In the preparation of culinary products, the following types of aromatic herbs are used: dill, parsley, parsnip, celery, marjoram, tarragon (tarragon), cilantro (coriander greens), hyssop, basil, mint (pepper, lemon), cumin, thyme, etc.

Processing legumes and grain vegetables. The bean and pea pods are sorted, washed and, breaking the ends, remove the veins connecting the leaves. Long pods are cut across into 2-3 parts.

Cobs corn milk-wax ripeness is cleaned immediately before cooking, so that the color does not change. In corn, the stem and base are cut off, while leaves fall along with the stem. Then remove the fibers covering the ears, and washed.

Processing dessert vegetables. Dessert vegetables include asparagus and artichokes.

At asparagus use young shoots. They are carefully cleaned of the skin, trying not to break off the head. The lower coarse part of the shoots is cut off and used for making mashed potatoes and cooking broths for asparagus soups. Peeled asparagus is placed in cold water. When all the asparagus is peeled, it is bundled and boiled. There are white and green asparagus. White asparagus is used for making sauces, mashed soups, boiled dishes with sauces, and green - mainly for side dishes.

Artichokes represent large inflorescences with a fleshy receptacle. When processing them, cut the stems, the upper coarse parts of the petals of the basket and remove the internal stamens. Slices are smeared with citric acid so that they do not darken.

Rhubarb Processing For food, juicy, young leaf petioles of basal leaves, which are pink in color, are used. Old petioles are not used for food, since a large amount of oxalic acid accumulates in them. Rhubarb is treated as follows: in young petioles, leaves are cut off, and in petioles with a hard coarse surface, peel off the skin with a knife and then washed. From rhubarb prepare sweet dishes (compotes, jelly), toppings for pies.

3. Change in carbohydrates during cooking - sucrose inversion, alcohol and enzymatic fermentation of sugars. The role of these processes in shaping the quality of catering products

Changes carbohydrates . Foods contain monosaccharides (glucose, fructose), oligosaccharides (di- and trisaccharose-maltose, lactose, etc.), polysaccharides (starch, cellulose, hemicellulose, glycogen) and pectin-like substances close to carbohydrates.

Sugar Changes. In the process of manufacturing various culinary products, part of the Sugars contained in them is split. In some cases, cleavage is limited by the hydrolysis of disaccharides, in others a deeper decomposition of Sugars occurs (fermentation, caramelization, melanogenesis).

Hydrolysis of disaccharides. Disaccharides are hydrolyzed by both acids and enzymes.

Acid hydrolysis takes place in such technological processes as cooking fruits and berries in sugar solutions of various concentrations (making stewed fruit, jelly, fruit and berry fillings), baking apples, boiling sugar with some food acid (making fudge).

Sucrose in aqueous solutions under the influence of acids attaches a water molecule and breaks down into equal amounts of glucose and fructose (sucrose inversion). The resulting invert sugar is well absorbed by the body, has high hygroscopicity and the ability to delay the crystallization of sucrose. If the sweetness of sucrose is taken as 100%, then for glucose this figure will be 74%, and for fructose - 173%. Therefore, the consequence of the inversion is a slight increase in the sweetness of syrup or finished products.

The degree of sucrose inversion depends on the type of acid, its concentration, and the duration of heating. Organic acids by inversion ability can be arranged in the following order: oxalic, citric, malic and acetic. In culinary practice, as a rule, acetic and citric acids are used, the first one is weaker than oxalic acid by 50, the second - 11 times.

Sucrose and maltose are subjected to enzymatic hydrolysis during fermentation and in the initial period of baking yeast dough. Sucrose under the influence of the enzyme sucrose breaks down into glucose and fructose, and maltose under the action of the enzyme maltase - up to two glucose molecules. Both enzymes are found in yeast. Sucrose is added to the dough in accordance with its formulation, maltose is formed during hydrolysis from starch. Accumulating monosaccharides are involved in loosening the yeast dough.

Fermentation. Sugars are subjected to deep decay during the fermentation of yeast dough. Under the influence of yeast enzymes, sugar turns into alcohol and carbon dioxide, the latter loosens the dough. In addition, under the influence of lactic acid bacteria, sugar in the test turns into lactic acid, which delays the development of putrefactive processes and promotes the swelling of gluten proteins.

Caramelization The deep decomposition of sugars when heated above their melting point with the formation of dark-colored products is called caramelization. The melting point of fructose is 98-102 ° С, glucose - 145-149, sucrose - 160-185 ° С. The processes occurring at the same time are complex and not yet sufficiently studied. They largely depend on the type and concentration of sugar, heating conditions, pH, and other factors.

In culinary practice, it is often necessary to deal with caramelization of sucrose. When it is heated during the process in a slightly acidic or neutral medium, a partial inversion occurs with the formation of glucose and fructose, which undergo further transformations.

For example, one or two water molecules (dehydration) can be split off from the glucose molecule, and the resulting products (anhydrides) can be combined with each other or with the sucrose molecule.

Subsequent heat exposure can lead to the release of a third water molecule with the formation of hydroxymethyl-furfural, which upon further heating can decompose to form formic and levulinic acids or form colored compounds.

Colored compounds are a mixture of substances of various degrees of polymerization: caramel (a substance of light straw color, soluble in cold water), caramel (a bright brown substance with a ruby \u200b\u200bhue, soluble in cold and boiling water), caramel (substance dark -brown, dissolving only in boiling water), etc., turning into a non-crystallizing mass (burning). Zhenzhka is used as a food coloring.

Caramelization of Sugars occurs when baking onions and carrots for broths, when baking apples, in the preparation of many confectionery and sweet dishes.

Melanoid formation. They understand the interaction of reducing sugars (monosaccharides and reducing disaccharides, both contained in the product itself and formed during the hydrolysis of more complex carbohydrates) with amino acids, peptides and proteins, leading to the formation of dark-colored products - melanoidins (from gr. melanos - dark). This process is also called the Maillard reaction, after the scientist who first described it in 1912.

The reaction of melanoidinogenesis is of great importance in culinary practice. Its positive role is as follows: it causes the formation of an appetizing crust on fried, baked dishes of meat, poultry, fish, and baked goods from dough; by-products of this reaction are involved in the formation of the taste and aroma of the finished dishes.

The negative role of the reaction of melanoidinogenesis is that it causes darkening of deep fat, fruit purees, some vegetables; reduces the biological value of proteins because amino acids bind.

Amino acids such as lysine, methionine, which are most often lacking in plant proteins, enter the melanoidin formation reaction with particular ease. After combining with sugars, these acids become inaccessible to digestive enzymes and are not absorbed in the gastrointestinal tract.

In culinary practice, milk with cereals and vegetables is often heated. As a result of the interaction of lactose and lysine, the biological value of the proteins of ready meals is reduced.

Posted on Allbest.ru

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Food Processing Technologies

Food production
Much has been written and said about the cultivation of animals, poultry, fish, crops for the mass production of food. However, the difficult path of food to the consumer does not end there. The “enriched” raw materials from the heavy agricultural heritage are processed. And the main dangers are yet to come.

Modern food production does not at all seek to neutralize the harm received by the product during the growing process. Its purpose is to mask flaws and sell the product to the consumer as quickly as possible. At the same time, it would be good to increase its mass and shelf life and not invest extra money. That is why adventures are just beginning on the thorny path of habitual food on our table.

The first and most important problem of modern food products is their microbiological contamination, chemical and mechanical pollution.

Bacillus cereus.
This species is ubiquitous in raw milk. The bacterium secretes two types of enterotoxins both in food and in the human body. There is a risk of B. cereus from milk powder. When reconstituted milk is stored at room temperature for several hours, the bacteria multiply and secrete enterotoxins. Such milk is a danger to consumers.

Listeria monocytogenes.
They cause listeriosis, which can cause death (mortality reaches 30%). Listeriosis is mainly affected by pregnant women, infants, people with weakened immune systems and transplanted organs.

Salmonella.
Salmonella enter the territory of the dairy plant with raw milk and in case of violations of technological processes. In particular, in the USA in 1965-1966. at one of the instant milk powder plants, the bacterium appeared in the product due to non-compliance with the pasteurization temperature regime and the lack of a drain valve on the pasteurizer. The source of salmonellosis was probably raw milk. In the mid-1980s, Salmonella ealing in one of the dairy plants in England was found in milk powder and mixtures for children. These products caused numerous diseases, and in one case led to death. As it turned out, the bacterium multiplied in the remnants of milk powder accumulated in small internal gaps on the walls of the drying unit. All actions for the destruction of Salmonella ealing were unsuccessful, the equipment was completely eliminated, production was closed.

Staphylococcus aureus.
Thermal treatment (pasteurization, sterilization) only helps to reduce the number of viable Staphylococcus aureus cells at the subsequent stages of the technological process, but does not destroy enterotoxin. Staphylococcus pasteurized milk products are contaminated due to irregularities in the technological processes or improper handling of the finished product, as well as from people - carriers of staphylococcus. In England in the 1950s, several foci of poisoning with skimmed milk powder were detected (1,200 children were affected). In Puerto Rick 775 children are sick after taking milk powder in the USA. As it turned out, after thickening, the milk was delayed for too long before drying, which created favorable conditions for the development of staphylococcus and the release of enterotoxin by it.

Escherichia coli.
The presence of Escherichia coli in the product indicates a low sanitary level of production and improper conduct of the processes. Diseases caused by E. coli have different symptoms depending on the strain of the pathogen.
Milk and products from it are most susceptible to microbiological contamination. The meat of healthy animals should not be contaminated with microorganisms. However, the deeds of nature are successfully corrected by man - microorganisms still settle on meat during slaughter and cutting. The most common sources of contamination are scalding, skinning, feathering, cooling, butchering, contamination of meat with fecal waste that may still be in the gut, as well as the presence of bacteria and other contaminants on the instrument and hands of workers. Here are just a few examples of cases of bacterial contamination in food production.

Chemical pollution
All chemicals when ingested in doses exceeding the permissible level can cause poisoning. They can act instantly, for example allergens (an allergic reaction), or after some time (heavy metal poisoning). Sources of chemical infections are considered raw materials, various materials (including packaging), machinery and equipment.

Ty yellow metals.
Heavy metal compounds can enter products from equipment and devices used in the dairy industry. Statistics record only acute diseases caused by the consumption of large doses of heavy metals. As a rule, poisoning occurs in an atypical way, and the diagnosis is not always correctly made.

Salts of nitric and nitrous acids (nitrates and nitrites).
Salts of nitric and nitrous acids are found in products. The sources of their appearance are drinking water, detergents for equipment, boilers used in factories. Doctors and hygienists consider it dangerous that salts of nitric and nitrous acids are found in food due to a possible blockade of the physiological functions of hemoglobin in the blood and stimulation of neoplastic processes.

Antibiotics and other medicines.
Antibiotics can get into food not only because of their content in raw materials. It is with the help of antibiotics that many manufacturers of products fight the possible microbiological infection of the product (see above). Antibiotics and their metabolic products can cause allergies or poisoning symptoms, reduce the sensitivity of pathogenic microflora (it becomes resistant to antibiotics), inhibit the activity of beneficial microflora, and contribute to the development of fungal diseases in humans.

Sanitary facilities.
Often chemical pollution occurs during washing and disinfection (up to 25% of cases of food poisoning). The presence of surface-active substances (surfactants) affects the organoleptic, technological and toxicological properties.

Technical pollution.
Ethese may be oils or technical lubricants for equipment. They penetrate into the products during maintenance work on the equipment. Operation of equipment and fittings made from inappropriate materials, such as copper, zinc, causes the transfer of substances from these materials into products. Doctors talk a lot and often about the health effects.

The fight against infection and pollution.
How do food manufacturers fight the chemical, and most importantly, the microbiological danger? Perhaps, there is no way to deal with the chemical, but you have to fight against microorganisms, because they affect the marketability of the product. We have already talked about the use of antibiotics that are applied to the inner side of the container, or injected into the product itself. Food preservatives are also used for this.
But there are other ways and technologies that cannot be classified as neutral for human health. For example, for the disinfection of meat, its radiation exposure is widely used. And although technologists assure that the radiation doses received by the product are microscopic, we know about the ability of radioactive elements to accumulate in the body.
For dairy products, it is true that there are a lot of tricks and ways to sell a low-quality product under the guise of an ordinary one, masking its shortcomings and dangers. Most often, such falsification occurs by adding water, hydrogen peroxide, sodium carbonate, sulfanilamides or antibiotics to it.

Mechanical pollution
Such contaminants can enter the product during production. For example, many bakeries use soft metal machines. When processing grain, such metal is shrunk and gets into flour. The same can happen during the processing of any products to be ground, for example, in semolina. Without special analyzes, fine needle metal dust is almost impossible to detect. Such cereals, or bread from such flour, can lead to gastritis and a chronic stomach ulcer.

Recipes and Technologies
Next comes the turn of cooking food. Modern technologists work tirelessly to reduce the cost of the production process, but at the same time maintain and even improve the presentation and shelf life of products. Chemistry goes towards them with leaps and bounds. And as a result, the product that lands on our table may look like quite normal and even mouth-watering, but it consists of an entire periodic table.

Extension of shelf life
To increase the shelf life of products, they are usually introduced preservatives . But they will not necessarily be contained in the product itself. The same antibiotics   used for keeping meat and other products in them for several minutes. Thus, it is possible to extend the "life" of meat by more than 2 times.
In some countries, poultry is treated with chlortetracycline, and it is also used as an additive to ice to transport fresh fish.
Fruits, most often citrus fruits, are dipped before storing in storage in a solution of diphenyl, a substance from the pesticide group. Apples are coated with a thin layer of wax with the addition of fungicide and grapes are fumigated with sulfur dioxide.
Manufacturers of meat products solve the problem of increasing the shelf life of raw materials and slowing down the inevitable rotting processes in meat as follows: add to minced meat and meat products sodium nitrate   and sodium nitrite having a "cosmetic" effect, giving the product a pink color. Studies show that sodium nitrite forms carcinogenic compounds in the human body, the so-called nitrosoamines, and also deprives the hemoglobin contained in the blood of the ability to deliver oxygen to body tissues. This compound is highly toxic for children, can cause fetal defects in pregnant women, and is especially dangerous for people suffering from anemia.

Sodium sulfite   destructive vitamin B is another carcinogen commonly found in meat. It prevents the appearance of a putrid odor and artificially gives the meat its “natural” red color, no matter how old and stale it actually is.

Nitrites and nitrates   (potassium nitrate and sodium E-249, E-250; potassium nitrate E-251, E-252) are added to sausages, sausages, smoked meats, some canned meat delicacies, as well as to salting mixes when salting meat.

Accelerating Technology
In modern food production, technologies are widely used to reduce the time for cooking food. As a rule, such catalysts of technological processes are substances that are far not indifferent to our body. For example, in the preparation of smoked sausages are widely used ripening accelerators.   The drying process of smoked sausage in normal conditions takes several weeks, and this is disadvantageous. Therefore, drying is carried out chemically, using substances that “draw” water from the product. The danger of these substances to humans is not officially confirmed, but not excluded, research is actively ongoing.

Process smoking , sausages, meat, fish, etc. - this is a long and expensive process, it is no coincidence that smoked meats are classified as delicious products. “Traditional” smoking transfers a valuable food product to the category of carcinogens, this was discovered thirty-forty years ago. And to speed up the process, manufacturers went even further. They developed the technology liquid smoked . That is, the product is simply dipped into the extract of chemical components and smoking smoke before drying. Smoked aroma with a spicy hue is 66% related to the presence of phenol and 14% to carbonyl compounds, and 20% to all other smoking components. Phenol   extremely toxic. Carbonyl compounds   these are formaldehyde, glyoxal, furfural (it smells of rye bread), acetone, glycolaldehyde and methylglyoxal, etc. The last two “components” give a golden smoked color to the “delicacy”, however, with the destruction of amino acids (proteins) of the product.

Technological Additives
We have already talked about nutritional supplements  marked E, which enriches the products during mass production on the way to our table.

However, this is not all. Almost all products are present genetically modified components . As a result of transformations, such products acquire new properties, for example, vegetables and fruits become toxic to insects and viruses that cause plant diseases, become larger and more resistant to herbicides.

In the sausage industry is widely used herbal protein preparations   - These are mainly soybean processing products. In the world while there is debate about how harmful or safe it is. But until research is completed, until the fact that it is safe is confirmed, its widespread introduction into our life is hardly justified. Moreover, almost any soy is transgenic. And the one that is not transgenic is much more expensive, which means it is not interesting to large producers.

Here is just a sample list of additives used by our meat industry:

protein stabilizers:
Pork skin. Milk protein concentrates (dry, liquid or pasty). Protein stabilizer made from pork skin, veins or tendons. Pressed pork mass after mechanical re-boning. Dairy products (whole and skim milk, dry or liquid cream). Protein preparations of plant origin are mainly products of soybean processing: Soy flour (mass fraction of protein in dry matter is not less than 45%). Soy concentrate (at least 65% protein). Soy isolate (at least 91% protein).

Nutritional supplements necessary in the technological process of food production:

• process accelerators;
• myoglobin fixatives;
• technological food additives (gelling agents, bleaches, etc.);
• food grade improvers;

It does not make sense to decipher the composition and properties of each such additive in detail, but in the end, little remains of the original product. And what remains is molded with the help of food casings.

Hazardous food casings.
For the manufacture of casings for sausages and cheeses, a synthetic polymer, polyvinylidene chloride, or PVDC is used. In Russia, the production of such shells is now increasing, since they are very cheap and "technological."

In our country, it is allowed to use the PVDC polymer in the production of sausage-cheese coatings, despite the danger of the transfer of toxic impurities from the shell into the product itself. Not even PVDC itself is harmful, but the substance from which it is produced - the monomer (ethylene, styrene, butadiene, phenol, etc.). When experimenting with laboratory animals, it was found that under the influence of these substances, mice develop hemangiosarcomas of the liver and kidneys. For some reason, this did not impress our supervisory authorities, and the polymer is widely used to date.

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