LESSON OBJECTIVES 1. To tell about the types of heat treatment of meat, the rules of cooking meat. To acquaint with the technology of cooking the first course in meat broth. Teach how to cook a meat dish. 2. Develop logical thinking, performing skills. 3. To cultivate an aesthetic taste, to instill the skills of work culture and accuracy.

Meat is a combination of different types of tissues: muscle, connective, adipose, bone. Proteins 14-20% Fats 2-37% Water 47-75% Minerals (salts of phosphorus, calcium, sodium, magnesium, iron) Vitamins A, D, PP, B. Fatty Connective Muscle Bone

Heat treatment of meat The main purpose of heat treatment is softening of products to improve their assimilation by the body. As a result of chemical changes that occur when heated, animal and plant proteins lose their original properties and become more susceptible to the effects of digestive enzymes. When cooked, new flavors and aromas are formed, which stimulate the appetite and promote better assimilation of food.

Heat treatment of meat Heat treatment neutralizes food from most microorganisms and toxins produced by them, from pathogens of helminthic invasions, corrects substandard raw materials and allows them to be used for food, allows you to cook various dishes from the same products. The rules of cooking when cooking meat: do not overcook or overcook food, do not overcook or overcook food, fry and cook over high heat at first, but bring it to readiness - on low; fry and cook first over high heat, and bring it to readiness - on weak. Overheating destroys vitamins, aromatic substances, changes the color of foods, and increases the loss of nutrients.

1. Cooking (main method, steaming, in a water bath, passing) 1. Cooking (main method, steaming, in a water bath, passing) Dishes made from boiled meat are less nutritious and are widely used in dietary nutrition. The prepared meat is placed in a saucepan and, filled with cold water, brought to a boil. Reduce heat, skim and cook until tender. The cooking time is: beef 22 hours 45 minutes, lamb 1.52 hours 10 minutes, pork 1 hour 45 minutes 2 hours, veal 1 hour 20 minutes 1 hour 45 minutes. The weight loss of meat products during cooking is 40% on average. When boiled, up to 25% of fat is transferred from meat to water. When the meat is punctured, no juice is released in the finished meat. The boiled meat is left in the broth and removed when it has cooled and cut across the fibers.

Boiled meat Boiled meat is prepared as follows: Water is taken at the rate of 1.5 liters per 1 kg of meat, so that it only covers the meat. The meat is cut into pieces weighing no more than 2 kg, placed in boiling water and, when it boils again, continue to cook with very low boiling or no boiling at a temperature of 8090 ° C. Roots (onions, parsley, carrots) are laid in 30 minutes, and spices and salt 15 minutes before being cooked. Vegetables and other additives are laid according to the recipe based on 1 kg of meat 15 g of vegetables, 0.1 g of bay leaves, 10 g of salt. For the meat to be juicy and tasty, it must be cooked without boiling, since the meat becomes tough when boiling. When cooking without boiling, the loss of extractives is reduced by 2025%. By-products are cooked in any way.

2. Frying 2. Frying For frying, the meat is cleaned, cut into a thickness of no more than 2 cm across the fibers, put in a frying pan with heated fat and fried on both sides until golden brown. It is advisable to beat off the meat and plan it. In the process of frying, the loss of meat mass is about 26% (with pre-breading, the loss is less). tenderer

3. Letting go 3. Letting go - boiling meat in a little water. The products (poultry fillets, chopped products) are placed in a single layer in a greased saucepan or low saucepan, salt and spices are added, a little water or broth is added so that they cover the products about 1/3 of their height. The product is brought to readiness by the action of steam formed from the moisture of the product itself. With this method of heat treatment, the loss of nutrients is reduced.

4. Stewing 4. Stewing Combined type of heat treatment, in which first the product is fried, and then boiled with seasonings and sauces. Stew the meat on low heat, under a closed lid. The most rational way to prepare second courses for children.

5. Baking 5. Baking Before baking, the meat is boiled, simmered, fried or stewed. The product is sprinkled with breadcrumbs and greased. Roasting is carried out in ovens, ovens, at a temperature of ° in metal molds, pans or dishes. The product is considered finished when a golden brown crust forms on its surface. The meat is baked just before serving. You can bake meat products with vegetables and sauce. Finished baked goods should not be stored as their appearance and taste deteriorate quickly.

6. Shearing 6. Shearing A method of heat treatment, when the product is first stewed in a small amount of broth and fat, and then fried in the oven (glaze). A combined method of heat treatment is also used, when the product is first boiled and then fried. This method is advisable to use for the preparation of products with a delicate consistency, such as brains, or vice versa, products containing a lot of connective tissue, not amenable to softening during frying.

7. Smoking Treatment of salted and windy meat products with smoke generated by the slow combustion of firewood and sawdust of some tree species, with a lack of oxygen. The preservative effect of smoking is due to the partial dehydration of the product and the bactericidal effect of smoking smoke. In the process of smoking, meat products acquire a unique aroma, exquisite taste, delicate texture, golden or brown color and, most importantly, the ability to long-term storage. Smoked products retain up to 90% of the beneficial properties, a lot of protein, vitamins A, B and C. They reduce blood cholesterol, so smoking meat is very beneficial for health!

Second courses from meat Dishes from boiled and fried meat. Natural lumpy semi-finished products, Natural portioned semi-finished products, Small lump natural semi-finished products, Shashlik, Poultry (goose, duck, chicken) Stew dishes. Meat, stewed in large pieces, Wind meat, Goulash, Stew, Plov, Azu. Baked meat dishes. Potato casserole with meat, Vegetables stuffed with meat, Pasta with meat. Chopped meat dishes. Rump steak, Beefsteak, Zrazy.

Portion semi-finished products Beefsteak - Beefsteak - a piece of irregularly rounded flesh 2 ... 3 cm thick Entrecote - Entrecote - a piece of oval-oblong flesh 1.5 ... 2 cm thick breadcrumbs

Minced meat products Cutlets - flat cakes of an oval shape Meatballs - meat balls, the minced meat must include rice Lyulya-kebab - an oriental dish in the form of an oblong cutlet fried on a skewer Meatballs - meat balls boiled in broth Bitochki - round cutlets Meat loaf - minced meat product baked in a mold

Classification of semi-finished products! SGT! SGT Attention! When cooking meat, use labeled tools and appliances. Semi-finished products Characteristics Heat treatment Shashlik Meat cubes weighing 30 ... 40 g Beef stroganoff Meat cubes 3 ... 4 cm long and weighing 5 ... 7 g Goulash Meat cubes weighing 20 ... 30 g Beefsteak A piece of irregularly rounded pulp 2 ... 3 cm thick Entrecote A piece of oval-oblong pulp 1.5 ... 2 cm thick Cutlets Chops A piece of oval-flat flesh with a bone Chopped mass Chopped meat in a meat grinder Cutlets Oval-flattened products with one pointed end 1.5 ... 2 cm thick, 9 ... 10 cm long

From the history of Beef Stroganoff Beef Stroganoff translated from French means "Stroganoff beef". Stroganov is the surname of the Russian count, who is credited with the invention of this dish. According to one version, it happened like this. Once again, the count arranged a large ball with abundant refreshments, and now, when the ball was already drawing to a close, the tsar's envoy arrived to the count. The order immediately came to the kitchen to fry and serve the meat. The cook, however, ran out of supplies, and he went for a trick: he collected the remains of the tenderloin, cut it into small pieces, fried it and poured it with sour cream. The dish was to the taste of the distinguished guest, the count, not bewildered, gave him his name, and the name of the cook has sunk into oblivion.

Fire cutlets Fire cutlets To prepare cutlets, skinless chicken meat is passed through a meat grinder twice, stale bread soaked in milk or cream is added, salted and mixed thoroughly. Minced meat is chopped again, softened butter is added and cutlets are formed. Before frying, they are greased with an egg and milk and rolled in stale white bread, cut into small cubes. This is one of the few products of culinary art, the author of which is known - the owner of a tavern in Torzhok, where Alexander Pushkin has stayed more than once: Dine at Pozharsky's in Torzhok at your leisure, taste fried cutlets and go lightly.

Glossary of Terms Shearing Shearing is the frying of products pre-steamed in broth in the oven. Sautéing Sautéing is a type of processing a product in a small amount of fat. Letting go Let’s letting go is cooking meat in a little water. Deboning Deboning is the separation of the pulp from the bones. Beefsteak Beefsteak is a round-flattened product, not coated. Rump steak Rum steak is an oval-shaped breaded product. Deep-frying Deep-frying - frying with a lot of fat.

Practical work "PREPARING STEAMED POTATOES" Inventory and utensils: Inventory and utensils: cutting board, knife, spoon, fork, plate, saucepan. Ingredients: Ingredients: Potatoes - 10 pcs .; Stew - 1 can; Onions -1 pc .; Dill greens - a bunch; Garlic - 2 cloves; Ground black pepper - to taste; Salt - 1 teaspoon; Carrots - 2 pcs.

Cooking technology Peel and dice the potatoes. Peel the carrots and cut into cubes or coarsely chop the carrots. Chop the onion into crumbs. Put potatoes, carrots, onions in a saucepan with water (! So that the water almost covers the contents). Put a jar of stew in a deep plate and mash it with a fork. Place the stew in a saucepan.

Add salt and black pepper, mix everything. Stir, reduce heat, cover and simmer until potatoes are tender (about 30 minutes). At the very end, add herbs and chopped garlic, mix everything and remove from the stove. Put the finished dish on a plate. Serve hot with black bread, pickles or fresh vegetable salad. Bon Appetit!

Reflection "Restaurant" Are you satisfied? I would eat more of this: _________________________________________________ Most of all I liked in the lesson ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ I almost digested information about: ________________________________________________________ ________________________________________________________ ____________________________________________ This restaurant ________________________________________________________ ________________________________________________________ ________________________________________________________ I ate ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ Please ___________

Homework § 3 pages Products for making lazy dumplings Flour - 4 glasses; Cottage cheese - 400 gr.; Sugar - 3 tbsp. spoons; Chicken egg - 4 pieces; Salt - 2 tbsp. spoons; Butter - 25 gr. (1/4 pack). Jam or sour cream, Tea, sugar.

Literature Technology. Service labor: Grade 7: textbook for students of educational institutions. 3rd ed., Rev. / ed. V.D.Simonenko. - M .: Ventana-Graf, Authors: O.A. Kozhina, N.V. Sinitsa, O.V. Taburchak, V.D. Symonenko.

Topic: Primary and thermal processing of meat.

Lesson objectives:

to acquaint with the types of primary and thermal processing of meat;

to form and develop skills for heat treatment of meat;

to instill the skills of a work culture;

foster respect for food.

Lesson type: combined.

During the classes.

Organizational moment (3-5 min.)

Checking readiness for the lesson.

Checking the payroll.

Communication of the topic and purpose of the lesson.

Repetition of the covered material (3-5 min.)

Explain the nutritional value of meat.

How is meat stored?

What types of meat do you know?

Give the characteristics of certain types of meat.

Explanation of the new material (25min.)

Primary processing of meat.

When starting to process products, you need to determine their freshness and quality. It is advisable to keep high-quality products in their natural form during culinary processing. Every housewife should know that only with the help of careful primary processing of products can a delicious dish be prepared.

The primary processing of meat includes defrosting, cleaning of contaminated places, removing the surface film, large tendons, brands, removing adhered paper, washing.

Defrost meat at room temperature, gradually. Do not defrost meat in water, as this will lose a significant amount of nutrients.

When preparing semi-finished products, such techniques as cutting, beating, cutting tendons, breading, stuffing, pickling are used.

You need to cut the meat across the fibers at a right angle or at an angle of 40-45 °, so that the pieces have a good appearance, are less deformed: for goulash - always with pieces of fat, for roast - with a tubular bone or joint, for stews - with a bone. The meat is beaten to loosen the connective tissue, smooth the surface and shape the pieces, which contributes to uniform heat treatment.

Breading semi-finished products to reduce the leakage of juice and evaporation of moisture: roll the pieces of meat in flour or breadcrumbs until the surface of these pieces no longer absorbs the battering material. The breading should be spread in a thin, even layer over the entire surface of the product. To better keep the breading, semi-finished products before breading can be moistened in a lezone - an egg-milk mixture. Lezon is prepared as follows: raw eggs are mixed with milk or water, salt is added. For one egg you need "1/3 cup of milk or" D glass of water, a pinch of salt. Breading contributes to the formation of a crispy, crispy crust.

Primary processing of offal. By-products include heads, brains, tongues, legs, liver, kidneys, spleen, udder, stomach (rumen), tails, ears, liver (heart, lung and throat). Frozen offal is thawed in the air. The water can thaw tongues, brains, kidneys, scars, udders. Brains are soaked in cold water for 1-2 hours to remove blood and swelling of the films. After that, the films are carefully removed without taking the brains out of the water. The blood vessels are cut out from the liver (the film is removed from beef), washed in cold water, periodically changing the water, then immersed in boiling water for 3-5 minutes, the mucous membrane is removed with a knife, and thoroughly washed again. Fat is separated from the beef kidneys, the kidneys are cut lengthwise, soaked in cold water for 2-3 hours. Pork, lamb and veal kidneys are not soaked. The udder is cut, large vessels are removed, washed in cold water. Beef legs are singed (if they are with wool), cleaned with a knife from the remnants of wool, the cornea is knocked off the hooves, cut into 2 parts and kept in cold water for 2-3 hours to eliminate the specific odor. For the same purpose, the tails of cattle, cut into separate vertebrae, are soaked in cold water for 5-6 hours. Leaver is divided into its component parts: heart, throat and lungs. The throat and heart are cut lengthwise, and blood clots are removed from the heart. The lungs are cut through the bronchi. After processing, the liver is thoroughly washed in cold water. The tongues are washed with cold water, dirt is removed from the upper part. The heads are scalded with hot water, thoroughly cleaned and washed.

Heat treatment of meat.

Cooking.

On average, the duration of cooking is: beef 2-2 hours 45 minutes, lamb - 1.5-2 hours 10 minutes, pork - 1 hour 45 minutes - 2 hours, veal - 1 hour 20 minutes - 1 hour 45 minutes. The meat of old animals is subjected to a longer heat treatment. The weight loss of meat products during cooking is 40% on average.

The loss of soluble substances in broths depends on the ratio of meat to water, the size of the pieces, the cooking time and is on average 2.3-2.6% of the mass of meat. The smaller the pieces, the more soluble substances are recovered.

During cooking, up to 25% of fat is transferred from meat to water, and 23-28% is melted during frying. Cooks recommend cooking boiled meat for second courses as follows: water should be taken at the rate of 1.5 liters per 1 kg of meat, so that it only covers the meat. The meat is cut into pieces weighing no more than 2 kg, placed in boiling water and, when it boils again, continue to cook with very low boiling or no boiling at a temperature of 80-90 ° C. Roots (onions, parsley, carrots) are laid in 30 minutes, and spices and salt 15 minutes before being cooked. For the meat to be juicy and tasty, it must be cooked without boiling.

From beef carcasses, for cooking and preparing second courses, use the scapula and the scapular part, the brisket, the edge, the lateral and outer part of the hind leg. Boiled meat is stored in a sealed container in a small amount of broth at a temperature of 50-60 °. When portioning, boiled meat is cut across the fibers.

Sausages and sausages are immersed in boiling water. If the sausages are in an artificial casing, they are carefully pricked with a fork and after boiling they can be easily removed. When the water boils again, the heating is weakened and heated without boiling for 5 minutes. It is not recommended to store cooked sausages and sausages hot for more than 20 minutes, as their shell may burst, and the minced meat will be saturated with water and will be tasteless.

Lowering.

A method of heat treatment, in which liquids are taken much less than for cooking. The food is placed in a single layer in a greased saucepan or low saucepan, salt and spices are added, a little water or broth is added so that they cover the food about 1/3 of their height. Then close the saucepan tightly with a lid and put it in a hot oven or on the stove. The product is cooked with steam.

Frying.

For the preparation of fried meat dishes, the tender parts of the beef carcass are used - the tenderloin, the dorsal and lumbar parts (thick and thin edge) and all parts of the veal carcass. Products and semi-finished products intended for frying must be salted immediately before cooking.

The most common way of frying is in a frying pan or other dish with a small amount of fat (5-10% by weight of the product) without adding water at a temperature. When frying, the food should only be placed in well-heated fat. Small pieces of meat, as well as portioned natural and breaded products are fried for 8-20 minutes (temperature 140-160 ° C). For frying in a frying pan, the meat is cleaned, cut into a thickness of no more than 2 cm across the fibers. When punctured with a chef's needle, colorless transparent juice should be released from the finished products.

Quenching.

Combined type of heat treatment, in which the product is fried first, and then boiled with seasonings and sauces. All types of meat can be stewed. Usually, from beef carcasses, the lateral and outer parts of the hind leg, the shoulder blade, the subscapular part, the edge (from the carcass of the 1st category) are used for stewing. In an acidic environment, collagen converts faster into soluble glutin. Therefore, during stewing, tomato is added to many dishes. The product is fried from all sides until a crust forms and placed in a deep stewing dish.

Breaking.

A method of heat treatment, when the product is first stewed in a small amount of broth and fat, and then fried in the oven.stew ... The product is sprinkled with breadcrumbs and greased. Roasting is carried out in ovens, ovens, at a temperature of 300-350 ° in metal molds, pans or dishes. The product is considered ready when it warms up to 80-95 ° and a golden brown crust forms on its surface.

Practical work "Determination of the quality of meat by the organoleptic method" (visual, olfactory, tactile and gustatory) (45 min.)

Current briefing.

Securing the material. Summing up the lesson. Reflection (5-7 min.)

What does the primary processing of meat include?

List the types of heat treatment.

Grading. Lesson analysis.

Homework (2-3 min.)

To retell the entries in the notebook. Write 3 recipes for meat dishes in a notebook.

This issue is considered in technology lessons in a comprehensive school. Let's give an example of development related to this topic.

Characteristics of meat

To begin with, the teacher must acquaint his pupils with the main characteristics of this food product. What are the features of the heat treatment of meat. The lesson on technology (grade 7) is aimed at a detailed study of the parameters of meat, as well as the features of its use as a food product. All technology lessons are aimed precisely at introducing theoretical knowledge about food processing into practice. This is what makes this subject interesting and exciting, gives girls the opportunity to feel like real housewives who can surprise relatives and friends with their culinary delights.

It is meat that is one of the most important nutritional components. It goes well with a variety of foods. A huge number of different dishes can be prepared from meat. The meat combines muscle, connective, adipose, and bone tissue.

This product has a high nutritional value. It contains fats, proteins, vitamins, minerals, extractives. Proteins contain amino acids that are identical in their characteristics to the protein of human muscle tissue.

Heat treatment of meat increases the ease of assimilation of this product. In the body, meat fats have a hard shell, located between the fibers. Heat treatment of meat leads to the melting of fats, which greatly facilitates their assimilation by the body. Due to the increased content of iron, phosphorus, aluminum, manganese, copper, zinc, B vitamins, fat-soluble vitamin A, nutritionists consider meat to be a unique storehouse of substances useful for the human body.

Working with the tutorial

At the stage of forming new knowledge, the teacher offers schoolgirls work with a textbook. Having studied the theoretical material, they fill out the table "Heat treatment of meat and meat products."

An example of eye exercises. You need to blink a few times, then close your eyes, count to five. Repeat the exercise five times. Close your eyes tightly, count to three, then open your eyes. Repeat the movements 4-5 times.

Extend your right arm forward. With your index finger, slowly move left and right, down and up, count to four, then look away, count to six.

Types of meat

Veal, beef, pork, lamb all require different processing temperatures. The teacher notes the importance of choosing a quality product. The freshness of meat can be determined by certain organoleptic parameters:

• appearance;
• smell;
• color;
• consistency;
• condition of subcutaneous fat, tendons, bone marrow;
• the quality of the broth.

Meat quality

Heat treatment of poultry meat in practice is realized only after the students have mastered theoretical knowledge. Children should learn that quality meat is covered with a thin, pale pink crust. When cut, the meat should not stick to the fingers; a good product has a dense consistency.

The veal is whitish pink, the cut beef is red and the pork is pinkish.

Primary processing of meat

Let's talk about how the primary heat treatment of poultry meat is carried out. A related technology lesson may be accompanied by a slide show. All stages of mechanical (primary) processing of meat products can be represented on them.

First, the meat must be thawed to room temperature. Then it is soaked in cold water, all dirty places are cut off. Further, excess fat, tendons, films are removed.

The meat is cut across the fibers, in which case its heat treatment is significantly accelerated. Cutting a chicken carcass involves dividing it into parts, separating the wings, legs, isolating

The fillet is cut into pieces, rolled in breadcrumbs, and semi-finished products are obtained.

Specificity of heat treatment of chicken meat

The teacher asks the students if they have an idea of ​​how it is possible to distinguish meat by the thermal state. Then there is a slideshow on the topic "Heat treatment of poultry meat".

The photos shown on the slides are a clear example of the appearance of meat, depending on the type of heat treatment chosen.

The guys enter the missing information into the table, make corrections in their entries.

Practical work

In the second lesson, work continues on this topic, involving the practical cooking of soup with chicken and cereals.

Each group works with a specific set of products:

• rice groats in the amount of 2/3 cup;
• carrots 1-2 pieces;
• onions - 2 pieces;
• fat - no more than 30 grams;
• chicken's meat;
• one egg;
• salt and pepper to taste.

For work, you will need white A4 paper, felt-tip pens, pencils, aprons, scarves. As an additional homework assignment, the teacher can invite girls to find material on issues related to the history of heat treatment of meat in Russia.

First, the girls talk about the nutritional value of meat, the stages of primary processing, and the sanitary and hygienic requirements for working with meat products.

The shoulder blade is suitable for a delicious stew. Pork breast is ideal for pilaf, the flesh of the shoulder blade is used in the manufacture of cutlets.

Jellied meat is boiled from pork legs, shanks, drumsticks, pork heads. When creating delicious meat dishes, all types of heat treatment are used: cooking, baking, stewing, stewing.

Having studied the theoretical material in the textbook, they talk about the primary processing of meat, cereals, vegetables.

All work is carried out under the strict guidance of a teacher. Girls work in aprons, kerchiefs to avoid hair getting into the soup.

The teacher controls every stage of the work, pays special attention to the heat treatment of meat.

At the final stage of the lesson, soups are supposed to be cooked in different groups. A prerequisite for each practical lesson in technology is table setting. For the tasting, girls can invite boys, a teacher, and other teachers who are not busy at the moment.

Conclusion

After the completion of the tasting process, an express survey is expected using special cards. Next comes the final word of the teacher. The teacher reminds the students that during the lesson various options for heat treatment of meat were considered.

The teacher notes that the acquired knowledge will become a good basis for improving culinary skills, can be used in everyday life.

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D For cooking, meat is boiled, allowed, fried, stewed and baked. You can also cook meat dishes in the pressure cooker, grilled and deep-fried.

Boiling

The meat is boiled in large pieces weighing 1.5-2 kg, placing them in boiling water (1-1.5 liters of water per 1 kg of meat). It is not recommended to boil meat in pieces weighing more than 2 kg. Large pieces are cooked unevenly and by the time the inner parts are ready, the surface layers of the piece are overcooked. When the ox boils, boiling is continued at a very slab boil.
The meat cooked in this way turns out to be more juicy and tasty than that laid in cold water, and then boiled at a strong boil.
Usually boiled parts of meat carcasses, which contain a significant amount of connective tissue. Under the influence of hot water, the connective tissue gradually swells, turns into glue, as a result of which the meat becomes soft. From parts of the beef carcass, boil the brisket, edging and parts of the front and hind legs. From carcasses of small livestock (veal, pork, lamb, horse meat), brisket and shoulder blades are used. Before boiling, cut the film along the ribs from the inside of the brisket; the pulp of the shoulder blade is rolled up and tied with twine.

When boiling meat, 30 minutes before its readiness, put onions, parsley, celery, carrots, bay leaves into the water. Vegetables are put about 15 g per 1 kg of meat, bay leaf 0.1 g. When cooking, salt is added to the water simultaneously with vegetables (10 g per 1 kg of meat).

The duration of boiling meat is different (from 1.5 to 3 hours) and depends mainly on different types of animals and their age, as well as on the part of the carcass and the size of the pieces taken for boiling.

As you know, the meat of young animals is boiled faster than that of old animals, and it is ready when the temperature of its inner layers reaches 70 °. Almost the readiness of the meat is determined by piercing the thickest part of the piece with a chef's needle. The needle enters the cooked meat easily, with the same force throughout the entire thickness of the piece, the juice flowing out at the puncture site is colorless.

The needle enters uncooked meat with much greater resistance in the inner layers than in the outer, flowing reddish juice in a boiling broth, it quickly coagulates.

It is possible to determine the readiness of meat by the temperature inside the piece, as well as by the color of the juice flowing from it, only from animals not older than 3 years of age. The meat of older animals, having warmed up during boiling to 70-80 ° and more, remains tough; the juice flowing from such meat is colorless, so it is continued to cook until it becomes soft.

The readiness of the meat of old animals is checked only by its consistency (by piercing the pieces with a chef's needle, as described above).

Corned beef before boiling is thoroughly washed, cleaned, cut into pieces weighing 1-1.5 kg and poured with cold water at the rate of 2 liters per 1 kg. Water is changed five times - after 1, 2, 3, 6, 12 hours, counting from the start of soaking. The water temperature should be no higher than 12 °. Food ice can be added to the water to maintain the required temperature.

In the warm season, when such prolonged soaking can lead to product spoilage, corned beef should be soaked in smaller pieces for 6 hours. Prepared soaked pieces of meat are poured with clean cold water at the rate of 3-5 liters of water per 1 kg of meat, depending on the salt content in the meat, and boiled at low boil. After 1.5-2 hours of boiling, add carrots, parsley, onions, bay leaves to the broth with corned beef and continue boiling until the meat is cooked. The broth after boiling corned beef is used for soups, mainly for cabbage soup and borscht.

The ham is boiled with a whole ham. A raw salted or smoked ham is soaked in cold water for 5-6 hours, and a roll - 3-4 hours, after which it is poured with fresh cold water for cooking. So that the thin part of the ham (thigh) is not digested, it is not completely immersed in water, but only up to the kneecap. To do this, the end of the tibia of the ham is tied with a rope, tying the ends with a loop, a stick is threaded into the loop and the latter is placed on the sides of the boiler. When the water in the cauldron with the ham boils, reduce the heat and cook the ham without boiling at a temperature of 80-85 °. The duration of cooking depends on the size of the pieces: a medium-sized ham (a large ham weighs 6 kg, the minimum weight is 2.5 kg) is cooked for 3-4 hours, a roll for 2.5-3 hours. The readiness of the ham is determined in the same way as the readiness of the beef, that is, by the cook's needle and by the fact that the iliac (pelvic) bone is separated from the finished ham without much effort.
If the ham needs to be stored after boiling, then, after taking it out of the hot broth, immerse it in cold water for 15-20 minutes, and then store it hanging in a cold room.

The brains, freed from the film, are placed in cold water, 10 g of salt, 10 g of 6% vinegar, 0.5 g of bay leaf are added to each kilogram of the product. When the water boils, the brains are boiled for another 25-30 minutes over low heat. Boiled brains are kept in a decoction. Brains can be boiled without vinegar.

Kidneys (beef) are soaked in water for 2-3 hours, then poured with fresh cold water and heated to a boil, the broth is drained, after which the kidneys are again poured with fresh water and boiled for 1-1.5 hours at low boil. Cooked kidneys are stored without broth in a sealed container.
Sometimes boiled beef kidneys contain kidney stones; in this case it is necessary to rinse the finely chopped kidneys in cold water.

The scars are poured with water, brought to a boil, boiled for 4-5 hours. 30 minutes before the end of cooking, 15 g of vegetables, 10 g of salt, 0.5 g of bay leaves are added to each kilogram of product.

Tongues are cooked like meat. Hot boiled tongues are poured with cold water and peeled off the skin from the warm ones.

The udder is cut into pieces of 1-1.5 kg, poured with cold water and cooked at a low boil for 2-3 hours. Cooked offal is stored in a cold room.

Sausages and sausages are placed in boiling salted water (15 g of salt per 1 liter). For every kilogram of sausages or small sausages - 2-3 liters of ox. Maintaining a weak boil, the sausages are heated for 3-5 minutes, the sausages - 7-10 minutes. With a longer heating, sausages and wieners become less tasty, and sometimes their shell bursts. You can also steam them. To give the best taste and appearance to sausages and wieners, after warming them up in water, they are fried in fat in an oven or on the stove.

Broths left after cooking meat products, if they do not have an unpleasant aftertaste, are used to make sauces and soups.

Cooking time for meat products

Lowering

Add chopped cutlets and meatballs, natural cutlets from veal loin. These products are placed in a greased stewpan, salt is poured half the height of the products with broth, butter is added, covered and boiled: chopped uncoated products - 20 minutes, natural pork and veal cutlets - 35-40 minutes.

Adding the products, it is good to add 1/2 lemon juice to the broth. lemon per 1 kg of product or citric acid. They improve the palatability of the product and give it a lighter appearance.

The simmered products are released with a white sauce cooked in the broth left over after the simmering.

Frying

The first varieties of meat of cattle, all varieties of meat from small livestock, piglets and rabbits are roasted. The meat is fried in large portions and small pieces, as well as in the form of cutlet mass.

Most often, meat is fried on a baking sheet or frying pan, but frying in a large amount of fat (deep-fried), on a spit and on a grill is also used. When frying large pieces of meat in a frying pan or baking sheet, after the fat poured in them has warmed up well (about 130-150 °), put the meat. In this case, a crust of hardened (coagulated) protein quickly forms on the meat, which prevents the juice from flowing out of the inner layers of the piece.

If you put the meat in a cold frying pan, the crust formation will be delayed, some of the juice will have time to flow out and the meat will turn out to be less juicy. However, you must not overheat the fat, because at an excessively high temperature (190-200 °), the fat begins to fume strongly, filling the kitchen with smoke. The burnt fat tastes disgusting, and besides, such fat is harmful to the health of those who eat it.

Large pieces of meat weighing from 0.5 to 2 kg are most often sprinkled with salt before frying and fried on all sides until a brown crust appears on the meat, after which the meat is fried in an oven at a temperature of 150-180 °.
This is how beef is fried - roast beef, veal, lamb, pork, loin, ham in whole or in parts, a shoulder roll rolled and tied with twine (thin twine), natural and stuffed brisket.

Large cuts of veal, lamb, pork, stuffed brisket, piglets, hares and rabbits are fried in an oven. Cuts of meat are most often sprinkled with salt before roasting. The piglets are sprinkled with salt on the inside and placed on a baking sheet, skin side up. For the formation of a more ruddy crust, the skin of the pig is smeared with sour cream.

Meat products, laid on a baking sheet, are placed in a hot oven and every 10-15 minutes are poured with fat on which they are fried. Fry from 30 minutes to 2 hours, depending on the size of the pieces and the type of meat. If the meat was fried correctly, then a golden crust should appear on the surface.
To determine if the meat is ready, the thicker parts of the piece are pierced with a chef's needle. The needle goes into raw meat with difficulty, and the flowing blood juice, falling on a hot baking sheet, coagulates. The needle passes easily and evenly into the finished fried meat, the flowing juice is transparent, falling on the baking sheet it does not curdle.

The ribs are removed from the fried brisket. To make them easy to remove, cut a film on the inside of the brisket along the ribs before frying. The finished fried meat is transferred from the baking sheet to another dish and stored until serving at a temperature of 40-50 °. It is necessary to carefully monitor the storage temperature of roast beef, fillets and other products that are cooked low and medium-fried so that they do not overcook.

A baking sheet with the fat and juice remaining on it after frying the meat is placed on the stove, the liquids are allowed to evaporate, the fat is drained, and the thickened extract remaining on the baking sheet is diluted with a small amount of water or broth (no more than 0.5 liters per 1 kg of roasted meat), boiled 5 -8 minutes, then filter. The brown extractive broth obtained in this way, or, as it is otherwise called, meat juice is used for watering fried meat before serving.

Langets, entrecotes, fillet steaks, lamb cutlets are fried in iron, cast iron and aluminum pans. It is better to fry natural pork and veal cutlets in low saucepans and on baking sheets, cast-iron pans. Pieces of portions are sprinkled with salt, pepper, placed in a well-heated frying pan, a baking sheet with fat, fried until crusts form on both sides.

Portions of natural beef and lamb are cooked low, medium and fully fried.
The degree of browning is determined by the color of the juice released when pierced with a chef's needle or the firmness of the meat when pressed.
Pork and veal cutlets are always fried until the bloody juice has completely disappeared.

Chops, schnitzels, rump steaks and liver are fried in iron pans and baking trays on the stove. If the meat, after the formation of crusts on both sides, is still not fried, it is fried for 5-8 minutes in an oven. Products breaded in white breading, it is advisable to fry in low saucepans. The pieces of meat are placed in a bowl with heated fat and fried until they are ready. In finished products, the juice flowing out when punctured with a needle should be colorless, not bloody.

Chopped cutlets, cue ball, schnitzels, zrazy are fried on the stove. The products are placed on a baking sheet or pan with fat heated to 130-150 °, fried on both sides until golden brown, and then placed in a hot oven for 5-8 minutes. Fried products, when pressed, release a colorless, transparent juice.

Breaded and natural portioned fried foods should not be stored for a long time; during storage, their taste decreases. From the fat and juice remaining in the dishes (after frying uncooked meat products), meat juice is prepared. This juice and fat is poured over natural (uncoated) pieces of fried meat while serving. Pieces breaded in breadcrumbs or white breading are poured with fat alone.

Brains, brisket, veal legs are deep-fried. To do this, the products are pre-cooked, cooled, and then breaded. Then they are immersed in highly heated fat (temperature 160-180 °). As soon as a golden brown crust forms, the products are removed from the fat with a slotted spoon, placed on a metal sieve to drain excess fat.

To completely warm the fried product, it is placed in a hot oven for 8-10 minutes.
As the fat becomes clogged by the particles of breading separated from the products (after about 5-6 times frying), the fat is filtered and reused.

Lamb, beef kebabs and tenderloin fillets are fried on a skewer. The meat, put on a skewer (hairpin), is slowly rotated in front of burning coals. In this case, the juice flowing from the meat can be collected by substituting some kind of dish.

Fillet, entrecote are fried on a wire rack (grill). The grate is pre-heated well, the rods are thoroughly cleaned and greased with a piece of pork fat.
Portions are placed on a grate set over hot coals. After frying on one side, they are turned over to the other.
When roasting on a skewer and on a grill, the coals must not smoke, otherwise the finished products will smell of smoke. The products are fried on a spit and a grill before serving them, since even with a short storage, the taste of the finished products deteriorates.

To prepare dishes from fried meat, large pieces of meat, cold or hot, are cut into portions, like boiled meat, across the fibers.
Cold portions for hot tempering are heated in a small amount of broth before serving. It is not recommended to heat fried meat for a long time, as it loses its juiciness and becomes tough.

Frying time for meat products

Extinguishing

Stew meat in pieces weighing up to 2 kg, as well as in portions and smaller pieces. Large chunks of stew are mainly beef and lamb. Pork is stewed most often in portions.
To give the meat a special taste and aroma during stewing, add spices, aromatic vegetables: carrots, parsley, celery, onions in an amount of 50 to 100 g per 1 kg of meat and low alcohol drinks. Low-alcohol drinks are added to sauces for stews, in an amount of 3-10% by weight of finished meat, white and red grape wine, beer and kvass (0.5 liters per 1 kg of meat). Wine is added to the sauce 10-15 minutes before the end of stewing.

Before stewing, pieces of meat are salted and fried on all sides together with vegetables in a deep saucepan, in a pan or baking sheet with melted beef lard until they form a crispy crust, along with onions, carrots, parsley and celery. Large pieces are fried in an oven, and portioned and smaller pieces are fried on the stove.

Vegetables can be fried separately. Before frying, portions are slightly beaten with a hoe and the tendons are cut. The fried meat is transferred to a dish (a basket, a deep stewpan and a cauldron), and large pieces are placed in one row. A baking sheet or stewpan in which the meat was fried is heated on the stove until the liquid evaporates. Then drain the fat, add a little broth or water and, stirring with a spatula, boil in order to dilute the condensed meat juice adhering to the bottom of the dish, which is then poured into a dish with fried meat together with vegetables, add broth or water (0.5 l per 1 kg of meat), put tomato puree, spices (bay leaf or coriander, cinnamon, basil in the amount of 0.5 g per 1 kg of meat) and stew the meat with a low boil in a tightly sealed container until tender.

So that large pieces of meat are cooked evenly during stewing, they are turned over every 12-15 minutes, using a cook's needle or meat fork, from one side to the other.

Duration of stewing of portioned pieces from 40 to 60 minutes, and large 2-2.5 hours. During stewing, the boiling liquid is replenished with water or broth.
Cooked meat, stewed in large pieces, is sometimes fried. To do this, put it on a baking sheet, pour the broth in which it was stewed, and put it in an oven for 5-10 minutes.

Wheat flour sauteed without fat is added to the broth left after stewing the meat and boiled for 25-30 minutes, then the sauce is filtered, rubbing vegetables boiled during stewing into it. The strained sauce is boiled for 5-10 minutes. Side dishes for stews are prepared with the stew and separately.

For brass beef, stew, pilaf, side dishes are cooked together with meat when stewing.

In the mass production of dishes, side dishes are prepared separately in the following way. Potatoes and vegetables, diced or wedged, are fried, covered with sauce made in stew broth, and cooked until tender. On vacation, the meat is poured with sauce with vegetables.
You can also prepare a side dish for the stew in the usual way. In this case, the meat is poured over with sauce, and the side dish is placed next to it.
Large pieces of stew are stored in a sealed container with low heat (50-60 °). For long-term storage, the meat is taken out in the refrigerator. Cut the meat (1-2 pieces per serving) before leaving. Cold portions are heated in sauce.

Baking

Pre-stewed, stewed or fried meat products are baked with sauce in portioned pans or dishes. The finished products are served in the same dishes in which they were baked. On vacation, pour over melted butter. Baked products should have a golden brown crust and be heated to 70-75 ° during baking.

Grill

Food is cooked in hot air without an open flame. At the same time, the maximum taste is achieved. Since the food is cooked without fat, it can be used as a dietary supplement. The grill can be on a wire rack, on a skewer or in a special dish on a gas stove.

An electric grill and a conventional grill work on the same principle, but the temperature is higher in the electric grill. If you are cooking on a grill that is built into an electric stove, do not close the stove door. When cooking on a charcoal grill, make sure that the melted fat does not drip onto the coals, otherwise it will burn with an unpleasant odor.

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• Content
• Introduction
• 1. Purpose of heat treatment
• 2. Changes in physical and chemical parameters and biological value of meat and meat products during heat treatment
• 2.1 Change in meat proteins during heating
• 2.2 Changes in fat when meat is heated
• 2.3 Change of extractives
• 2.4 Vitamin changes
• 2.5 Change in water holding capacity
• 3. Color formation
• 4. Formation of taste and smell
• 5. Organoleptic characteristics
• Conclusion
• Literature

Introduction

Heat treatment is one of the most commonly used technological processes in meat production. The main purpose of cooking is to bring the product to a culinary state. Since this increases the resistance of the product to microbial spoilage, heat treatment is used as one of the preservation methods. Meat and meat products are usually heated from 60 to 180 "C. The action of high temperatures (above 100" C) is the most reliable method of canning, allowing you to get canned food that can be stored for 3-5 years. At lower temperatures, the barrier effect of heat treatment is reduced, which affects the timing of snoring. So, cooked foods cannot be stored for a long time, they must be quickly sold.

Heat treatment of products is carried out in different ways: immersion in a liquid medium, exposure to a vapor-air mixture, live steam, electric contact heating, microwave energy, infrared heating, as well as a combination of the above methods.

According to their technological purpose, these methods can be divided into main and auxiliary ones.

The main methods of heat treatment mean such a change in the properties of a product, as a result of which it becomes edible (sausage and culinary products, canned food) or passes into another qualitative state (fat melting, gelatin extraction, etc.).

Auxiliary methods include those in which the processed raw material does not undergo significant changes (scalding, scorching, pre-drying, etc.) or acquires specific properties (roasting, blanching, etc.) necessary for the production of the corresponding product. This treatment usually has a negligible barrier effect.

Heat preserving includes sterilization, pasteurization, boiling and baking.

Sterilization is the main link in the technological process in the manufacture of canned food. It consists in heat treatment of meat at temperatures above 100 "C, as a result of which the microflora is destroyed.

Pasteurization is carried out at a temperature of 100 ° C and below. It also ensures the microbiological safety of canned food and its storage capacity. The shelf life of pasteurized canned food is shorter than that of sterilized food.

Cooking is widely used in the production of sausages, ham and other products. During the cooking process, up to 99% of microflora is destroyed, so it does not guarantee the complete destruction of microflora and especially spores. Consequently, cooked foods cannot be stored for a long time, they must be quickly disposed of.

Sterilization and cooking are carried out in a humid heating environment (water, steam), steam-air mixture). Baking is a dry heating method.

Baking is carried out with hot air to a temperature in the center of the finished product of 68-70 ° C, which, just like during cooking, limits the shelf life of finished products.

1. The purpose of the heat treatment

The main goals of heat treatment:

1) fix the structure of the meat product;

2) bring the product to a state of culinary readiness;

3) destroy vegetative forms of microorganisms and increase the storage resistance of products;

4) to form the required organoleptic characteristics of the finished product (appearance, color, taste, smell, consistency) is achieved by using various technological methods with a specific purpose.

Heat treatment of meat and meat products causes structural, physicochemical and other changes in them, the depth of which depends on temperature.

2. Changes in physical and chemical indicators and biological value of meat and meat products during heat treatment

In the course of heat treatment, complex changes occur in raw materials and meat products, associated with the penetration of heat into the product and ambiguously affecting the quality of the finished product (Fig. 1).

Rice. 1. Changes in the product during heat treatment

The depth of these changes depends mainly on the temperature reached inside the product, the duration and method of heating, the presence of water in the product itself or in the heating medium, etc.

2.1 Change in meat proteins during heating

When heated, a protein molecule undergoes complex physicochemical changes, primarily denaturation and coagulation, the depth of which depends on temperature, duration of heat treatment and some other factors.

Proteins of animal origin are thermolabile: their denaturation begins at 40 ° C and increases rapidly with increasing temperatures. Basically, the process of denaturation of most of the muscle proteins is completed at temperatures of 68-70 ° C, and at 80 ° C, muscle proteins are denatured almost completely.

Denaturation of muscle proteins, cooking and hydrothermal disaggregation of collagen find their external expression in changes in the structural and mechanical characteristics of heated products, as well as their geometric dimensions.

When products with intact cellular structure are cooked, the integrity of muscle fibers is preserved, but they become denser and decrease in diameter due to protein denaturation. At the beginning of heating, collagen fibers of the sarcolemma become transparent, their crimp decreases, and their thickness increases. At a temperature of 65 ° C, the bundles contract, lose their fibrous outlines, become less dense, more glassy. Areas with destroyed collagen, filled with glutin, appear, and why the destroyed tissue acquires a granular structure. The degree of destruction depends on the properties of the connective tissue, temperature and duration of heat treatment. The rougher the connective tissue membranes, the more resistant they are to heat.

Heat treatment of meat, which contains a small amount of connective tissue, leads to a thickening of the meat structure as a result of coagulation of muscle proteins.

Influence of temperature and heating method on the rate and temperature of protein denaturation

The rate of thermal denaturation depends on temperature, humidity, heating method, and other factors. Denaturation is inhibited by the addition of certain substances, such as pyrophosphate, polyhydric alcohols, sugars and P-actin, although the mechanisms of inhibition are different. The rate of denaturation of ATPase increases with the breakdown of muscle protein as a result of a decrease in the size, density, and symmetry of the molecules. The rate of protein denaturation also depends on several other factors. For example, denaturation of fibrinogen with urea accelerates with an increase in urea concentration and with a decrease in pH below 7, however, in the pH range of 7.0 ... 8.6, the reaction rate is almost constant. The presence of heavy water stabilizes the native structure of enzymes due to the presence of hydrogen bonds, reducing the rate of inactivation.

It has now been established that the proteins that make up the meat denature as the temperature reaches a certain temperature for each protein (Table 1). Myosin is the most sensitive to heating. In the temperature range 45 ... 50 ° C, the main part of the structural proteins of the muscles denatures. Sarcoplasmic proteins (myogen and myoglobin) denature at higher temperatures (55 ... 70 ° C). The most resistant to denaturation are myoproteins (most of the enzymes), as well as hemoglobin, serum albumin, collagen.

Table 1

It has been established that denaturation occurs stepwise, that is, when a protein reaches a certain temperature, it acquires a corresponding structure with certain properties.

Changes in charged groups and pH of proteins during heat treatment of meat

In the process of thermal denaturation and subsequent coagulation, structural changes of proteins occur, the breaking of old bonds and the formation of new bonds with the participation of hydrogen bonds, sulfhydryl, disulfide, acidic and basic groups of proteins and hydrophobic interactions.

R. Gamm showed that heating meat in water from 20 to 70 ° C causes a stepwise decrease in the number of carboxyl groups in myofibril proteins, while the number of basic groups does not change significantly. Significant changes in acidic groups begin at 40 ° C. In the interval 40 ... 50 ° С, their number decreases, at 50 ... 55 ° С it remains unchanged. At temperatures above 55 ° C, the number of acidic groups continues to decrease, and at a temperature of about 60 ° C, it decreases very significantly. The total decrease in the number of acidic groups when heated to 70 ° C is 85%. At temperatures from 70 to 120 ° C, along with a further reduction in the number of acidic groups, a decrease in the number of basic ones begins.

A change in the ratio of charged (acidic and basic) groups as a result of denaturation and post-denaturation transformations is associated with a change in pH. At the same time, the fact of a direct correlation between the pH value of raw materials, water retention capacity and the yield of the finished product has been established. The higher the initial pH value of the raw material, the better the quality (juiciness) of the finished product. The magnitude of the pH changes depends on the temperature and the heating method, the initial pH value of the raw meat.

The magnitude of the pH shift is also influenced by the anatomical origin of the muscles. With an increase in the heating temperature, the water-retention capacity changes and the isotope of fibrillar proteins shifts to higher pH values, and the number of main groups increases. During thermal denaturation, the isotope also shifts to higher pH values, apparently due to the splitting of hydrogen bonds and the release of additional positive charges.

Change in muscle solubility and disaggregation of connective tissue proteins

The solubility of proteins is one of the indicators characterizing their denaturation changes. It is known that heating is accompanied by a decrease in the solubility of proteins. Intramolecular bonds broken during denaturation interact intermolecularly, resulting in particle aggregation. In other words, denaturation changes in protein macromolecules, changing the surface layer of the molecule, lead to a violation of the ratio of hydrophilic and hydrophobic groups towards an increase in the latter, which leads to a decrease in solubility.

With traditional heating methods, the precipitation of sarcoplasmic proteins is observed at a temperature of about 40 ° C, and most strongly at a pH of 5.5. The bulk of these proteins coagulates in the range of 55 ... 65 ° C. There is information about the presence of heat-resistant proteins: for example, adenyl kinase can withstand temperatures of about 100 ° C.

The change in collagen under the influence of heat is a complex process that consists of two stages: collagen digestion and hydrolysis. Collagen is a glycoprotein in which the content of covalently bound carbohydrates varies depending on the source of the protein. The soluble part of collagen - procollagen and insoluble - collastromin differ in denaturation temperatures and the nature of denaturation transformations. Denaturation of procollagen proceeds in two stages and ends at a temperature of 36.5 ° C, thus forming a homogeneous transparent mass that passes into solution. Collastromin becomes homogeneous at higher temperatures or with longer exposure to heat.

In the temperature range 62 ... 64 ° C, when heated in water, collagen fibers instantly shrink, which, folding three times in relation to their original length, turn into a rubbery mass. In the process of shrinking, the three-helical structure of the peptide chains of individual collagen molecules takes the form of a coil. However, unstructured peptide chains are still linked by covalent bonds and cannot go into solution.

As a result of wet heating of collagen-containing tissues, polydisperse decomposition products are formed. With slow heating, high-molecular-weight compounds predominate, with intense heating, compounds with a lower molecular weight. When collagen is cooked, about 60% of the mucoids contained in the tissue pass into the solution.

Since the welding and hydrothermal disaggregation of collagen reduce the strength properties, the meat, which contains a lot of connective tissue, becomes less tough after heating. However, if the degree of destruction of the tissue structure is too great, the meat disintegrates into separate fibers due to a violation of the connection between the bundles of muscle fibers, united by the connective tissue layers.

It follows from this that a certain degree of collagen breakdown, sufficient to soften the tissues, but no more than that at which their noticeable breakdown begins, should correspond to the achievement of the culinary readiness of the product. According to the Institute of Nutrition of the Russian Academy of Medical Sciences, the state of culinary readiness is achieved when 20-45% of the collagen of the connective tissue breaks down.

For products that contain little connective tissue, culinary readiness is determined by the denaturation of soluble proteins, since with an increase in heating time, their rigidity and tissue dehydration increase. In practice, for this it is enough to warm up the product to the full depth of about 70 ° C.

Several other factors also affect collagen disaggregation during heating. A shift in the pH of meat from the isoelectric point enhances disaggregation, an increase in the age of animals from one to one and a half years reduces it by about 2 times. Thus, the degree of collagen disaggregation and the formation of decomposition products depend not only on the temperature to which the product is heated, the state and composition of the meat, but also on the speed, and, consequently, on the heating method.

Coagulation of proteins and its effect on qualitative changes and the structure of meat products

The process of heating proteins is accompanied by the deployment of globules and the release of free radicals, in connection with which there is the possibility of the formation of intermolecular bonds, aggregation of particles and their precipitation, which leads to a decrease in the solubility of proteins.

Internal rearrangement of a protein molecule - denaturation itself - manifests itself in the aggregation of polypeptide chains. The aggregation process takes place in two stages: enlargement of the particle size without leaving the solution and subsequent coagulation. Aggregation of denatured protein molecules, or a change in their quaternary structure, which is a consequence of the previous rearrangement of the secondary and tertiary structures, is accompanied by a reduction in the lyophilic centers of the protein molecule and a decrease in the water-holding capacity of meat. Aggregation and coagulation of proteins determine the formation of a continuous spatial framework of the finished product.

The rearrangement of the protein molecule upon denaturation worsens the hydrophilic and enhances the hydrophobic properties of the tissue; therefore, the protective (stabilizing) effect of the hydration layers near the polar groups is weakened. Intramolecular bonds are replaced by intermolecular ones, an insoluble clot is formed, i.e., coagulation of proteins occurs (flakes fall out of dilute solutions, coagel falls out of concentrated solutions).

The process of protein denaturation is accompanied by the destruction of the structure of water, as a result of which the secondary forces acting between protofibrils (van der Waals forces) give the myosin molecule a more compact form, while part of the liquid is released.

As a result of denaturation and coagulation of muscle proteins, the strength properties of meat increase, while collagen boiling and its subsequent hydrolysis, on the contrary, weaken them.

2.2 Changes in fat when meat is heated

Heat treatment of meat and meat products causes the destruction of the complex intracellular colloidal system, which contains fat. At the same time, it melts and then coalesces, forming a homogeneous phase in the cell in the form of a drop. If the fat cells have been destroyed before heat treatment or are destroyed during heating, the melted fat flows out, merging into a single bulk phase. In cases where heating takes place in an aqueous medium, a small part of the fat forms an emulsion with water.

With a sufficiently long heating with water (including with intracellular water), fat undergoes significant chemical changes, with moderate - they are small, but easily detected. Table 2 shows the changes in some characteristics of beef fat, which was heated with water at 100 ° C for 1 hour in the presence of a small amount of sodium chloride.

Influence of wet heating of fat on changes in some of its qualitative characteristics

Table 3

Changes in the acid number of fat under the influence of high-temperature heating

An increase in the acid number indicates the hydrolytic breakdown of fat, a decrease in the iodine number indicates the saturation of unsaturated bonds of fatty acid radicals, an increase in the acetyl number indicates the addition of hydroxyl groups to fatty acid radicals. Against the background of a decrease in the iodine number, an increase in the acetyl number can be considered evidence of the addition of hydroxyl groups at the site of double bonds as a result of the interaction of triglycerides with water.

If hydrolysis of fat on a small scale does not lead to a decrease in nutritional value, then the addition of hydroxyl groups to acid radicals is a direct evidence of a decrease in the nutritional value of a part of the fat.

Under conditions of wet and prolonged heating at temperatures above 100 ° C, hydrolytic processes are significantly accelerated, namely, hydrolysis of triglycerols and saturation of double bonds of fatty acid radicals with hydroxyl groups (Table 3).

When cooking meat products and bones in a large amount of water during boiling (broths, soups), part of the melted fat is emulsified, being distributed throughout the broth in the form of tiny balls. The emulsified fat gives the broth an unpleasant greasy flavor and turbidity. Fat emulsification is enhanced with increasing hydrolysis and boiling intensity. Periodic removal of fat from the surface of the broth reduces the degree of its emulsification.

When specified in table. 3 parameters, the iodine number of fat decreases even more noticeably, and the more intense, the higher the temperature. Since, along with this, the acetyl number increases, there is reason to believe that the formation of hydroxy acids occurs.

Table 4

Changing the properties of beef fat reused for frying products

Under dry heating conditions, such as frying, oxidative changes in fats and polymerization processes come to the fore. Table 4 shows some of the characteristics of re-used beef fat.

An increase in the saponification number indicates the accumulation of low molecular weight acids, and the acetyl number indicates the formation of hydroxy acids.

In the process of heating, the peroxide value of fat increases and the content of acrolein in the fat increases significantly. The color of the fat darkens, the smell worsens mainly as a result of the transfer of colored products of pyrogenetic decomposition of organic substances into it. With prolonged use of fat for frying, the digestibility decreases as a result of the accumulation of oxidation and polymerization products in it. Heating fat to high temperatures even under vacuum leads to a slight decrease in the iodine number and an increase in its viscosity.

Linolenic and linoleic acids are primarily subjected to oxidation, polymerization and cyclization. In this case, the formation of six-membered unsaturated cyclic compounds, oxidized polymers and other substances harmful to the body is possible. These processes become noticeable at high heating temperatures, therefore, when frying, the fat temperature should not exceed 170 ° C.

Heating the broth at 100 ° C for an hour prevents the fat from going rancid. This appears to be due to the formation of antioxidants.

During sterilization, fats and their oxidation products interact with proteins, forming complexes - proteolipids and liponroteins. These processes, along with the formation of hydroxy acids, reduce the nutritional value of meat products.

2.3 Change of extractives

During heat treatment, the extractive substances of meat undergo significant changes, which play a decisive role in the formation of the specific aroma and taste of cooked meat. After boiling, the meat, thoroughly washed from water-soluble substances, has a very weak odor, and the water extract from it has the taste and smell of boiled meat. After dialysis, this extract almost loses the smell of boiled meat.

The changes that cause this odor are not yet fully understood. It is known, however, that glutamic acid and inosinic acid degradation products play an important role in this. Glutamic acid and its sodium salt, even in small amounts (0.03%), give the product a taste close to that of meat.

When heated, the decomposition of inosinic acid increases: at 95 ° C, about 80% of the acid decomposes after 1 hour, with the formation of predominantly hypoxanthine. In this case, the amount of inorganic phosphorus slightly increases as a result of the formation of phosphoric acid.

During the cooking process, the content of other extractives also changes. About 1/3 of the bitter-tasting creatine is converted to creatinine. Decomposes about 10 ... 15% of choline. As a result of the decomposition of compounds containing labile bound sulfur, hydrogen sulfide is formed in boiled meat, the amount of which depends on the type and condition of the meat, as well as on the cooking conditions. It increases with increasing temperature and increasing heating time. There is less hydrogen sulfide in boiled beef than in pork, and there is less hydrogen sulfide in it than in veal, in frozen meat there is more than in chilled meat. The release of hydrogen sulfide at moderate temperatures is associated with the breakdown of glutathione (a tripeptide formed by glutamic acid glycine and cystine), since it occurs when glutathione sulfur disappears. Simultaneously with the release of hydrogen sulfide as a result of the breakdown of glutamine and glutathione, glutamic acid is formed. The introduction of oxidizing agents (nitrite, nitrate) reduces the rate of hydrogen sulfide formation. When meat is cooked into broth, substances are released, which include carbonyl groups with different aromas. Acetaldehyde, acetoin, diacetyl were found in the broth. These substances arise due to the reaction of the interaction of free amino acids with reducing sugars (including glucose), which leads to the formation of melanoidins.

In a complex redox reaction, carbonyl compounds are released as by-products.

Low molecular weight fatty acids (formic, acetic, propionic, butyric, isobutyric), which also have a pronounced aroma, were found in the broth obtained by boiling low-fat beef using the chromatographic method.

It can be assumed that the specificity of the smell of cooked meat is associated with the composition of the lipid fraction of muscle tissue, since the smell of different types of lean meat differs little.

The question of exactly what substances give meat its specific aroma and taste after heat treatment has not yet been fully resolved. However, the relationship between the taste of meat and the content of free purines in it, in particular hypoxanthine, has been experimentally proven. The amount of these substances in muscle tissue is different and depends on the depth of development of post-mortem changes in the tissues. Ketobutyric acid also has a broth smell.

2.4 Vitamin changes

Heat treatment of animal products at moderate temperatures (up to 100 ° C) reduces the content of some vitamins in them due to chemical changes, but mainly as a result of losses to the environment. Depending on the method and conditions of heat treatment, the meat loses,%: thiamine 30 ... 60, pantothenic acid and riboflavin 15 ... 30, nicotinic acid 10 ... 35, pyridoxine 30 ... 60, part of ascorbic acid. When cooking products in a casing, the loss of vitamins is somewhat less. So, during steam cooking, 25 ... 26% of thiamine and 10 ... 20% of riboflavin are lost, and when cooking in water - 10% of thiamine and 14% of riboflavin.

Thus, heat treatment of animal products, even at moderate temperatures, leads to some decrease in their vitamin value. Heating at temperatures above 100 ° C causes a different degree of destruction of many vitamins contained in meat.

Table 5

The degree of destruction depends on the nature of the vitamins, temperature and heating duration. Table 5 shows the results of changes in vitamins in the process of heating pork, depending on the temperature and duration of heating.

Ascorbic acid (vitamin C) is also destroyed and the more, the higher the temperature and the longer the heating. Of the fat-soluble vitamins, vitamin D is the least stable, which begins to break down at temperatures above 100 ° C. Vitamin A content in the absence of oxygen changes little when heated up to 130 ° C. Vitamins E and K are the most resistant to heat.

Dry heating in contact with air, for example, when frying meat products, causes an even more intensive destruction of vitamins, especially those that are easily oxidized (vitamins A, E, C).

2.5 Change in water holding capacity

Water is a natural component of meat, forming stable structured systems with other parts of it. The shape and strength of the water bond in these systems affect the properties of meat, including the water-holding capacity, by the nature of the change in which one can judge about the change in weight loss during heat treatment and about the quality of the product. At present, the water-holding capacity of meat is understood as the force with which part of its own water or its own with a small amount of added water is retained by proteins, as well as other substances and structural systems of meat when exposed to any external forces.

Many factors affect the change in the water-holding capacity of meat during its heat treatment: the temperature to which it is heated, the duration of exposure at it, the temperature of the medium, the method of heat treatment, the heating rate, the pH value of the processed raw materials, rheological characteristics, the chemical composition of the product, the amount of added table salt, water, type of meat, anatomical origin of muscles, age of animals, etc.

Most researchers associate the decrease in water-binding capacity and moisture loss during heating of meat only with a change in the conformational structure of the protein.

Changes in the proteins of muscle and connective tissues during heating lead to shrinkage and a decrease in the volume of meat and meat products with an intact structure, which is associated with the release of water. The amount of moisture lost by the product affects not only the hardness, but also determines the yield of the product.

Water loss is significantly affected by the degree of development of coagulation phenomena, which are accompanied by a decrease in the water-binding capacity.

Studies of the dependence of the decrease in moisture content on the temperature and pH of the minced meat sample showed that the separation of moisture begins already at a temperature of 35 ° C. However, starting from temperatures of 45 ... 50 ° C, moisture is released more intensively. This is explained by a change, on the one hand, in the structure of water at the indicated temperatures, and on the other, by the conformation of the protein macromolecule, which is caused by a complex of intra- and intermolecular hydrogen bonds and hydrophobic interactions.

Since heating is accompanied by the destruction of water structures (hydrogen bonds and hydrophobic interactions), the secondary van der Waals forces acting between protofibrils pull the protein molecule into a more compact form, i.e. polymerization of discrete proteins and an increase in their molecular weight occur. At the same time, with an increase in temperature, the contact of water with hydrocarbon leads to an energetically less favorable replacement of the water - water interaction with the carbon - water interaction, the protein structure becomes denser, which causes a significant release of moisture in the form of a broth.

The most important in reducing moisture loss is the choice of such modes of heat treatment, which should be only minimally necessary according to the characteristics of the composition and properties of the product. This is due to the fact that an increase in temperature in the range of 75-90 ° C by 1 ° C causes an increase in mass loss by an average of 0.37% versus 0.25% when heated from 65 to 75 ° C and 0.14% - when heated from 55 to 65 ° С

The water-binding capacity of meat products subjected to heat treatment can be increased by using fresh or well-ripened meat, as well as by shifting the pH to one side or the other from the isoelectric point of proteins (phosphates, organic acids). Table salt in relatively small quantities increases the water-binding capacity, in large quantities - reduces.

In addition to changes in the structure of water, denaturation changes in muscle proteins and disaggregation of collagen, the pH of the raw material has a significant effect on the change in water retention capacity.

The pH change in the process of heating meat is more strongly influenced than the temperature of the heating medium, by the pH of the feedstock and the temperature of the sample. Despite the fact that with an increase in the latter, the increase in pH increases (the magnitude of the increase depends on the pH of the initial minced meat), its water retention capacity decreases, since in parallel the isoelectric point of fibrillar proteins shifts to higher pH values.

physical chemical biological heat meat

3. Color formation

During heat treatment of muscle tissue, changes in myoglobin are very important, which determines the color of the meat: at 60 ° C, the red color remains inside the meat, at 60-70 ° C, which corresponds to the denaturation temperature of myoglobin, the emulsion is intensely colored pink. As a result of denaturation, the color of myoglobin is lost, it becomes insoluble.

It should be noted that the higher the heating temperature, the less stable the color of meat products. Exceeding the regulatory level of the final temperature in the center of the product during cooking (up to 75-80 0 С) leads to a change in the color of the meat and a gray-brown tint.

Myoglobin forms a compound with nitric oxide, the color of which (red) does not change when heated. This explains the stable color of corned beef, sausages, sausages, since saltpeter is added to the salted mixture.

4. Formation of taste and smell

Glutamic acid plays an important role in the formation of the taste of cooked meat. Its appearance when exposed to heat on meat is possible as a result of the release of amino acids from proteins and deamination of glutamine, which is located in muscle tissue.

The melanoidin formation reaction, or the Maillard reaction, plays an important role in the formation of the aroma and, in part, the taste of meat when heated. This is an interaction reaction between amino groups of free amino acids, polypeptides or proteins and carboxyl groups of carbohydrates.

The Maillard reaction is a series of reactions resulting in the formation of intermediate products that cause the appearance of a characteristic odor - carbonyl compounds (aldehydes, ketones, volatile acids), sulfur-containing compounds, etc. The end products of these reactions are melanoidins - dark brown polymers (fig. 2).

Rice. 2. The scheme of formation of melanoidin

Under normal conditions, this reaction proceeds very slowly, its consequences affect only during long-term storage. Heating dramatically accelerates its flow. The rate of formation of melanoidins and their intermediates depends on the temperature and duration of exposure to heat. Therefore, in the most obvious form, the consequences of this reaction are manifested during sterilization, baking and frying.

From the consumer, technological, and medico-biological points of view, the effect of melanoidins on food products is assessed ambiguously. They have a positive effect on aroma at moderate heating temperatures and negatively affect the color, causing the conquest of canned and fried foods. Melanoidins, formed during the culinary processing of food, are not broken down by human digestive enzymes.

Sulfur-containing amino acids, which are part of the protein, release hydrogen sulfide during destruction, and other compounds are formed - mercaptans. Sulfur-containing compounds play a leading role in the formation of the smell of cooked meat. Thus, more than 25 sulfur-containing substances were found in the volatile components of cooked meat. During the heat treatment of meat, phosphatides and phosphoproteins are cleaved during destruction with the formation of phosphine (PH 3). Also, heating meat is associated with the melting of fat and with its partial emulsification. Simultaneously with the melting of the fat, some volatile compounds are released, which impart flavor to the meat and broth. The composition of high molecular weight compounds of the cooked product also includes volatile low molecular weight fatty acids (formic, acetic, propionic, butyric, etc.).

The nature of the formation of flavoring substances in meat, as well as their losses during heat treatment, significantly depend on the type of product, its structure, method and technique of heating, on the presence or absence of a protective shell on the surface of the product. It was found that the softer the heat treatment regimes, the more pronounced the meat flavor of the finished products.

5. Organoleptic indicators

As a result of heat treatment, the meat acquires new characteristic taste, aromatic qualities, a dense consistency, becomes more stable during storage and is usually better absorbed. At the same time, there is a change in its biological value.

It is heating that causes changes in the constituent parts of meat responsible for the appearance of meat taste and aroma. Extractive substances play a decisive role in the formation of the taste and smell of cooked meat. Quantitative changes in many extractive substances are due to two oppositely directed processes: their accumulation as a result of the disintegration of high-molecular compounds and a decrease due to their own disintegration under the influence of heating and losses into the environment.

The loss of water-soluble proteins and extractives during cooking determines the taste and aroma of the broth. When meat is immersed in cold water, the mass fraction of these substances is much higher than when immersed in boiling water. In the latter case, rapid coagulation of proteins occurs in the surface layer. Therefore, in sausage production, products are immersed in boiling or heated water to 95 ° C.

Conclusion

Nutritional and biological value of meat and meat products is due to a number of both positive and negative aspects. After heat treatment, meat proteins become more accessible to the action of digestive enzymes, which is especially important for collagen. Therefore, heating increases the level of their digestibility and absorption. At the same time, prolonged heating can increase the resistance of proteins to enzymes due to the development of post-denaturation changes. This is typical for sterilized meat.

Heating causes inactivation and destruction of vitamins, especially water-soluble ones. As a result of the release of moisture, part of the water-soluble proteins, amino acids, extractives, and fatty acids is lost. The products of the Maillard reaction are difficult to digest in the body and can provoke carcinogenicity.

During the heat treatment of meat and meat products, a number of biochemical, physicochemical and microbiological processes take place, as a result of which the hygienic safety of products is ensured, their culinary readiness, organoleptic properties are formed, and storage stability is increased. The fundamental orientation of these phenomena remains for all types of heat treatment. At the same time, due to the specifics of the technologies of certain types of meat products, each of them has its own distinctive features.

Literature

1. Technology of production of public catering. In two volumes. Volume 1. Physical and chemical processes in food products during their culinary processing; A.S., Ratushny, V.I. Khlebnikov, B.A. Baranov; Mir Publishing House, 2003

2. D.V. Ketselashvili, Technology of meat and meat products, part 2; Kemerovo Technological Institute of Food Industry; 2004

3.L.G. Vinnikova, Technology of meat and meat products; "Firm" Inkos "2006

4. Biryukova V.V., N.V. Shevchenko Technology of production of public catering products; Omsk State Technical University 2004

5. Nechaev A.P., Traubenberg S.E., Food Chemistry, 2003

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