Functions of proteins and carbohydrates. Meat, canned meat and semi-finished products. Fruits and canned fruits

LECTURE No. 2

Topic: Proteins, fats, carbohydrates, minerals and vitamins, their role in nutrition. Consumption standards.

The qualitative composition of nutrition is the content of proteins, fats, carbohydrates, mineral salts and vitamins in the diet. All nutrients according to their primary purpose can be divided into 3 groups:

1) proteins and mineral salts: calcium and phosphorus- with a predominantly plastic function;

2) fats and carbohydrates- with a predominantly energy function;

3) vitamins and mineral salts(micro- and macroelements) - substances that perform a specific function as catalysts for metabolic processes in the body.

The qualitative composition is the basis for the development of standards for the consumption of various food products, ensuring the necessary supply of its individual components with food, both in quantitative and qualitative terms.

PROTEINS AND THEIR IMPORTANCE IN NUTRITION

Proteins are essential substances necessary for life, growth and development of the body. Lack of protein in the body leads to the development of nutritional (from the Latin alimentum - food) diseases.

Proteins are used as plastic material for the construction of various tissues and cells of the body, as well as hormones, enzymes, antibodies and specific proteins. Proteins are a necessary background for the normal metabolism of other substances in the body, in particular vitamins and mineral salts.

Proteins are also involved in maintaining the energy balance of the body. They are of particular importance during periods of high energy expenditure or when food contains insufficient amounts of carbohydrates and fats. Protein replenishes 11-13% of expended energy.

All proteins are usually divided into simple(proteins) and complex(proteids). Simple proteins are understood as compounds that include only polypeptide chains, while complex proteins are compounds in which, along with the protein molecule, there is also a non-protein part.

Simple proteins include albumins, globulins, and glutelins. Albumins and globulins constitute the main part of proteins in blood serum, milk and egg whites. Glutelins are plant proteins and are characterized by a low content of amino acids such as lysine, methionine and tryptophan.

Complex proteins include nucleoproteins, glycoproteins, lipoproteins, phosphoproteins, the non-protein group of which consists of nucleic acids, lipids, carbohydrates, phosphoric acid, etc.

Protein forms the basis of protoplasm and cell nuclei, as well as intercellular substances. Specific proteins are important. For example, the protein globin (part of the hemoglobin of red blood cells), myosin and actin provide muscle contraction, γ-globulins form antibodies. A protein in the retina (rhodopsin) ensures normal light perception.

The main constituents and structural components of a protein molecule are amino acids. The biological properties of proteins are determined by their amino acid composition and digestibility. The nutritional value of proteins is determined by the qualitative and quantitative ratio of the individual amino acids that form the protein.

During the digestion process, food proteins break down into amino acids, which, moving from the intestines into the blood and then into the tissues, are used for the synthesis of protein in the body.

Of the 80 known amino acids in nutritional science, 22-25 amino acids are of interest, which are most often present in proteins in food products used by humans.

Distinguish replaceable And irreplaceable amino acids.

Replaceable amino acids can be synthesized in the body. These include: alanine, aspartic acid, proline, serine, tyrosine, cystine, cysteine, etc.

Irreplaceable amino acids are not synthesized in the body and can only be obtained from food. Currently, 9 amino acids are considered essential: valine, histidine, methionine, tryptophan, threonine, phenylalanine, lysine, leucine, isoleucine.

The most complete complex of essential amino acids contains proteins of animal origin (meat, fish, eggs, milk, dairy products).

In some products plant origin also contains all essential amino acids, but either in small quantities or general content The protein in these products is small (in cabbage, potatoes - less than 1-2%).

To fully and most optimally meet the body's need for amino acids, 60% of the daily amount of protein in an adult and 80% in children should come from animal products.

The need for protein depends on age, gender, nature of work activity, etc. The body does not have protein reserves and requires a constant supply of protein from food in the amount of 80 - 120 g.

If the amount of protein in the diet is small, then a state of negative nitrogen balance is established, indicating that the consumption of tissue proteins exceeds the supply of essential amino acids with dietary proteins.

FATS AND THEIR IMPORTANCE IN NUTRITION

Fats in the human body play both an energetic and plastic role, being a structural part of cells. Fats serve as a source of energy that surpasses the energy of all other nutrients. The combustion of 1 g of fat produces 37.7 kJ (9 kcal), while the combustion of 1 g of carbohydrates and 1 g of protein produces 16.7 kJ (4 kcal).

Fats are good solvents for a number of vitamins and sources of biologically active substances. They participate in the construction of body tissues, being part of the protoplasm of cells. Protoplasmic fats ensure the permeability of substances - metabolic products.

The main importance determining the properties of fats is fatty acid, which are divided into marginal (saturated) and unsaturated (unsaturated).

Marginal (saturated) fatty acids found in large quantities in animal fats. In terms of biological properties, saturated fatty acids are inferior to unsaturated fatty acids. It is believed that saturated fatty acids have a negative effect on fat metabolism.

Unsaturated (unsaturated) fatty acids found primarily in vegetable oils. They contain double unsaturated bonds, which determines their significant biological activity. The most common are oleic, linoleic, linolenic and arachidonic fatty acids, which play a large role in the regulation of metabolic processes in cell membranes, as well as the processes of energy production in mitochondria.

Polyunsaturated fatty acids (acids with several free bonds) are not synthesized in the body; the need for them can only be satisfied through food.

The supply of the required amount of polyunsaturated fatty acids is ensured by taking 25-30 g vegetable oil in the daily diet of an adult.

A lack of unsaturated fatty acids in the diet leads to skin changes (dryness, flaking, eczema, hyperkeratosis), increases susceptibility to UV rays, and increases permeability blood vessels, affects the contractility of the heart muscle.

Fats also contain vitamins A, D, E (tocopherol) and pigments, some of which have biological activity. These fat pigments include β-carotene, sesamol, and gossypol.

Requirement and rationing of fats. Fat rationing is carried out taking into account age, gender, nature of work activity, national and climatic characteristics. Fat should provide 33% of the daily energy value of the diet, which, according to modern data, is optimal. The total amount of fat in the diet is 90 – 110 g.

The biologically optimal ratio in the diet is 70% animal fat and 30% vegetable fat. In adulthood and old age, the ratio can be changed towards increasing the specific gravity of vegetable fats.

CARBOHYDRATES AND THEIR IMPORTANCE IN NUTRITION

Carbohydrates are the main integral part food ration. The physiological significance of carbohydrates is determined by their energy properties. Each gram of carbohydrate provides 16.7 kJ (4 kcal).

Carbohydrates are also used in the body as a plastic material, for biological synthesis, and are part of the structures of many cells and tissues. For example, glucose is constantly found in the blood, glycogen is in the liver and muscles, galactose is part of brain lipids, lactose is part of human milk.

Carbohydrates are deposited in the body to a limited extent and their reserves are small. Therefore, to meet the body's needs, carbohydrates must be supplied uninterruptedly as part of food. Carbohydrates are closely related to fat metabolism. Excessive intake of carbohydrates into the human body with insufficient physical activity contributes to the conversion of carbohydrates into fat.

In natural foods, carbohydrates are presented in the form of mono-, di- and polysaccharides. Depending on the structure, solubility, speed of absorption and use for glycogen formation, carbohydrates in food products can be presented in the following diagram:

Simple carbohydrates

Monosaccharides:

glucose fructose galactose

Disaccharides:

sucrose lactose maltose

Complex carbohydrates

Polysaccharides:

starch glycogen pectin substances fiber

Simple carbohydrates have good solubility, are easily absorbed, and are used for the formation of glycogen.

Most common monosaccharide glucose found in many fruits and berries, and is also formed in the body as a result of the breakdown of disaccharides and starch in food.

Fructose has the same properties as glucose and is distinguished by increased sweetness among other sugars. Contained in bee honey, persimmons, grapes, apples, pears, watermelons, currants, and other products.

Galactose not found in free form in food products. Galactose is a breakdown product of the main carbohydrate in milk, lactose (milk sugar).

Disaccharides represented by sucrose, lactose and maltose.

Sources sucrose in human nutrition are mainly cane and beet sugar. Natural sources of sucrose in the diet are melons, bananas, apricots, peaches, plums, and carrots.

Lactose(milk sugar) is found in milk, has a low sweetness and promotes the development of lactic acid bacteria, which suppress the action of putrefactive microflora. Lactose is recommended in the diet of children and the elderly. The lactose content in the milk of farm animals is 4-6%.

Polysaccharides characterized by the complexity of the molecular structure and poor solubility in water. Complex carbohydrates include starch, glycogen, pectin and fiber.

Starch has basic nutritional value. In human diets, starch accounts for about 80% of the total amount of carbohydrates consumed.

Glycogen found in significant quantities in the liver.

Pectic substances represented by pectin and protopectin. Under the influence of pectin, putrefactive intestinal microflora is destroyed. Apples, oranges, apricots, plums, pears, carrots, and beets are high in pectin.

Cellulose enters the human body with plant products. During the digestion process, it promotes the movement of food masses through the intestinal canal. Fiber helps remove excess cholesterol from the body. Sources of fiber are legumes, vegetables, fruits, and wholemeal bread.

Need for carbohydrates. The total amount of carbohydrates in the diet is recommended depending on energy costs, gender, age and other indicators in the amount of 250-440 g. The amount of sugar, honey, sweets should not exceed 60-70 g per day. The ratio of simple and complex sugars in the diet is recommended 1: 3-4.

MINERAL ELEMENTS AND THEIR IMPORTANCE IN NUTRITION

Modern research confirms the vital importance of mineral elements. The importance of such biologically active substances as biomicroelements has been established. Rational consumption of minerals is necessary to prevent a number of endemic diseases: endemic goiter, fluorosis, caries, strontium rickets, etc.

Classification of mineral elements

Mineral elements alkaline (cations)	Mineral elements acidic in nature	Biomicroelements
		Strontium
		Manganese
		Antimony, etc.

The physiological significance of mineral elements is determined by their participation:

in the formation of structures and the implementation of the functions of enzyme systems;

in plastic processes in the body;

in the construction of body tissues, especially bone tissue;

in maintaining the acid-base state and normal salt composition of the blood;

in the normalization of water-salt metabolism.

Alkaline mineral elements (cations).

Calcium is the most common mineral element, which is contained in the human body in an amount of 1500 g. About 99% of calcium is found in the bones, participates in blood clotting processes and stimulates the contractility of the heart muscle.

Sources of calcium are milk and dairy products: 0.5 liters of milk or 100 g of cheese provides the daily requirement of an adult for calcium (800 mg). For pregnant and nursing mothers - 1500 mg per day. Children should receive 1100-1200 mg of calcium per day, depending on age.

Magnesium plays a significant role in carbohydrate and phosphorus metabolism, has antispastic and vasodilating properties.

The main sources of magnesium are cereals: cereals, peas, beans. Animal products contain very little magnesium.

An adult's need for magnesium is 400 mg per day. Children - 250-350 mg per day depending on age.

Sodium participates in the processes of extracellular and intertissue metabolism, in maintaining acid-base balance and osmotic pressure. Sodium mainly enters the body with table salt. Sodium intake is 4-6 g per day, which corresponds to 10-15 g of sodium chloride. The need for sodium increases with heavy physical work, profuse sweating, vomiting and diarrhea.

Potassium. The importance of potassium lies primarily in its ability to enhance the removal of fluid from the body. Dry fruits are high in potassium - dried apricots, apricots, dried cherries, prunes, raisins. Potatoes contain a significant amount of potassium. The daily requirement of potassium for adults is 3-5 g.

Mineral elements of an acidic nature (anions) - phosphorus, chlorine, sulfur.

Phosphorus, like calcium, is involved in the formation bone tissue, have a value in the function nervous system and brain tissue, muscles and liver. The ratio of calcium and phosphorus in food should not exceed 1: 1.5.

The largest amount of phosphorus is found in dairy products, eggs, and fish. The phosphorus content in cheese is up to 600, egg yolk- 470, beans - 504 mg per 100 g of product.

An adult's need for phosphorus is 1200 mg per day.

Chlorine enters the body mainly with sodium chloride. Takes part in the regulation of osmotic pressure, normalization of water metabolism, as well as in the formation of hydrochloric acid stomach glands

Chlorine is found mainly in products of animal origin: eggs - 196, milk - 106, cheese - 880 mg per 100 g of product.

The need for chlorine is 4-6 g per day.

Sulfur is part of some amino acids - methionine, cystine, cysteine, vitamins - thiamine and biotin, as well as the enzyme insulin.

Sources of sulfur are mainly products of animal origin: cheese contains 263, fish - 175, meat - 230, eggs - 195 mg per 100 g of product.

The need for sulfur in adults is approximately determined at 1 g/day.

Biomicroelements presented in food products large quantities, but is characterized by pronounced biological properties. These include iron, copper, cobalt, iodine, fluorine, zinc, strontium, etc.

Iron plays important role in hematopoiesis, normalization of blood composition. About 60% of iron in the body is concentrated in hemochromogen - the main part of hemoglobin. The largest amount of iron is found in the liver, kidneys, caviar, meat products, eggs, nuts.

An adult's iron requirement is 10 mg/day for men and 18 mg/day for women.

Copper is the second (after iron) hematopoietic biomicroelement. Copper promotes the transfer of iron to the bone marrow.

Copper is found in liver, fish, egg yolk and green vegetables. The daily requirement is about 2.0 mg.

Cobalt is the third biomicroelement involved in hematopoiesis, it activates the processes of formation of red blood cells and hemoglobin, and is the starting material for the formation of vitamin B 12 in the body.

Cobalt is found in liver, beets, strawberries, and oatmeal. The need for cobalt is 100-200 mcg/day.

Manganese activates the processes of bone formation and hematopoiesis, promotes fat metabolism, has lipotropic properties, and affects the function of the endocrine glands.

Its main sources are herbal products, especially leafy vegetables, beets, blueberries, dill, nuts, legumes, tea.

The requirement for manganese is about 5 mg per day.

Biomicroelements are iodine and fluorine, they are associated with endemic diseases.

Iodine participates in the formation of the thyroid hormone - thyroxine. It is distributed unevenly in nature. In areas with low natural iodine content in local products, endemic goiter occurs. This disease is characterized by an enlargement of the thyroid gland and disruption of its function.

Prevention of endemic goiter includes specific and general events. Specific measures include the sale of iodized salt to the population in order to ensure a daily intake of about 200 mcg of iodine into the human body.

Fluorine plays a significant role in the processes of tooth development, the formation of dentin and tooth enamel, as well as bone formation. It should be noted that the main source of fluoride for humans is not food, but drinking water.

VITAMINS AND THEIR IMPORTANCE IN NUTRITION

Vitamins are low molecular weight organic compounds that differ in their chemical structure. Vitamins are not synthesized in the body or are synthesized in small quantities, so they must be supplied with food. They take part in metabolism and have big influence on health status, adaptive abilities, and ability to work. A prolonged absence of a particular vitamin in food causes vitamin deficiency (hypovitaminosis). All hypovitaminosis is characterized by common symptoms, which include weakness, increased fatigue, decreased ability to work, and susceptibility to various colds. An increased intake of vitamins into the human body leads to hypervitaminosis (for example, hypervitaminosis of vitamins A and D in children).

The modern classification of vitamins is based on the principle of their solubility in water and fat.

Classification of vitamins

Fat soluble vitamins	Water soluble vitamins	Vitamin-like substances
Vitamin A (retinol)	Vitamin B 1 (thiamine)	Pangamic acid (vitamin B 15)
Provitamin A (carotene)	Vitamin B 2 (riboflavin)	Para-aminobenzoic acid (vitamin H 1)
Vitamin D (calciferols)	Vitamin PP ( a nicotinic acid)	Orotic acid (vitamin B 13)
Vitamin K (phylloquinones)	Vitamin B 6 (pyridoxine)	Choline (vitamin B 4)
Vitamin E (tocopherols)	Vitamin B 12 (cyanocobalamin)	Inositol (vitamin B 8)
	Folic acid	Carnitine (vitamin B T)
	Vitamin B c (folacin)	Polyunsaturated fatty acids (vitamin F)
	Vitamin B 3 ( pantothenic acid)	S-methylmethionine sulfonium chloride (vitamin U)
	Vitamin H (biotin)
	Vitamin N ( lipoic acid)
	Vitamin C (ascorbic acid)
	Vitamin P (bioflavinoids)

Fat-soluble vitamins.

VitaminA(retinol) found in products of animal origin. In products of plant origin it is found in the form of provitamin A - carotene. Retinol regulates metabolic processes, stimulates the growth of the body, increases its resistance to infections, affects the condition epithelial tissue. With a lack of vitamin A, there is dryness of the epithelium of the skin and mucous membranes, impaired twilight vision, in severe cases - damage to the cornea of ​​the eye, and stunted growth in children.

Vitamin A is found in fish oil, liver, eggs, cheese, and butter. Carotene is found in carrots, pumpkin, tomatoes, apricots, and rose hips. The richest green plants in carotene are the leaves of nettle, dandelion, spinach, sorrel, dill, and parsley.

The need for vitamin A depends on a person’s age and physical activity. Children, as well as women during pregnancy and breastfeeding, need increased amounts of this vitamin. The daily requirement for an adult is 1000 mcg. for pregnant women - 1250 mcg. Children under the age of 1 year should receive 400 mcg, from 1 year to 3 years - 450, from 4 to 6 years - 500, from 7 to 10 years - 700, from 11 to 17 years - 1000 mcg.

Group vitaminsD(calciferols). The vitamin D group includes vitamins D 2 (ergocalciferol) and D 3 (cholecalciferol). The source of vitamin D formation in the body is 7-dehydrocholesterol. When the skin is exposed to ultraviolet rays, vitamin D 3 is formed.

Plant organisms contain the provitamin vitamin D - ergosterol. Yeast is characterized by a high content of ergosterol.

Vitamin D normalizes the absorption of calcium and phosphorus salts from the intestines and promotes the deposition of calcium phosphate in the bones. A lack of vitamin D in the body causes a disturbance in calcium and phosphorus metabolism, leading to the development of rickets in children, which is manifested by delayed ossification of the fontanelles and teething. A number of general disorders are also noted - weakness, irritability, sweating.

The daily requirement for vitamin D for adults and adolescents is 100 IU (International Units), for children under 3 years old - 400 IU, for pregnant women and nursing mothers - 500 IU.

The main sources of vitamin D are fish products: cod liver and liver fish fat, herring, etc. Not a large number of Vitamin D is also found in dairy products.

Vitamin E (tocopherols). The effect of vitamin E is diverse: it regulates the reproductive function, affects the pituitary gland, adrenal glands, metabolism, and stimulates muscle function.

Vitamin E is found in significant quantities in vegetable oils, cereal germs, green vegetables and other foods.

The daily requirement of an adult for vitamin E is approximately determined at 12 mg; for pregnant women and nursing mothers it is 15 mg; children and adolescents should receive 5-12 mg depending on age and gender.

Group vitaminsK(phylloquinones). Vitamins of group K are involved in blood clotting processes. In the adult body, vitamin K is synthesized by intestinal microflora (mainly Escherichia coli), so vitamin K deficiency is rare in humans.

The main components of all living cells are proteins, fats, the functions and properties of these compounds ensure the vital activity of organisms living on our planet.

Fats are natural, complete esters of glycerol and fatty acids with one base. They belong to the group of lipids. These compounds perform a number of important functions of the body and are an indispensable component in the human diet.

Classification

Fats, the structure and properties of which allow them to be used as food, are divided by their nature into animal and vegetable. The latter are called oils. Due to the high content of unsaturated fatty acids in them, they are in a liquid aggregate state. The exception is palm oil.

Based on the presence of certain acids, fats are divided into saturated (stearic, palmitic) and unsaturated (oleic, arachidonic, linolenic, palmitoleic, linoleic).

Structure

The structure of fats is a complex of triglycerides and lipoid substances. The latter are phospholipid compounds and sterols. Triglyceride is an ethereal compound of glycerol and a fatty acid, the structure and characteristics of which determine the properties of fat.

The structure of the fat molecule general view is displayed by the formula:

CHˉO-CO-R’’

CH2-OˉCO-R’’’,

In which R is a fatty acid radical.

The composition and structure of fats have in their structure three unbranched radicals with an even number of carbon atoms. most often represented by stearic and palmitic, unsaturated - linoleic, oleic and linolenic.

Properties

Fats, the structure and properties of which are determined by the presence of saturated and unsaturated fatty acids, have physical and chemical characteristics. They do not interact with water, but are completely decomposed in organic solvents. They are saponified (hydrolyzed) if they are treated with steam, mineral acid or alkalis. During this reaction, fatty acids or their salts and glycerol are formed. They form an emulsion after vigorous shaking with water, an example of this is milk.

Fats have energy value approximately equal to 9.1 kcal/g or 38 kJ/g. If we convert these values ​​to physical indicators, then the energy released by consuming 1 g of fat would be enough to lift a load weighing 3900 kg by 1 meter.

Fats, the structure of their molecules determines their basic properties, have high energy intensity when compared with carbohydrates or proteins. Complete oxidation of 1 g of fat by the release of water and carbon dioxide accompanied by the production of energy twice as high as the combustion of sugars. To break down fats, a certain amount of carbohydrates and oxygen are needed.

In the human body and other mammals, fats are one of the most significant suppliers of energy. In order for them to be absorbed in the intestine, they must be emulsified with bile salts.

Functions

Fats play an important role in the mammalian body; the structure and functions of these compounds in organs and systems have different meanings:

In addition to these three main functions, fats perform several specific ones. These compounds support cell activity, for example, provide elasticity and healthy looking skin, improve brain function. Cell membrane formations and subcellular organelles retain their structure and functioning thanks to the participation of fats. Vitamins A, D, E and K can only be absorbed in their presence. Growth, development and reproductive function also largely depend on the presence of fats.

Body need

Approximately a third of the body’s energy expenditure is replenished by fats, the structure of which makes it possible to solve this problem if done correctly. organized diet. Calculation daily requirement takes into account the type of activity and age of the person. Therefore, the most fat is needed by young people who lead active image life, for example, athletes or men engaged in heavy physical labor. At sedentary life or a tendency to be overweight, their number should be reduced to avoid obesity and related problems.

It is also important to take into account the structure of fats. The ratio of unsaturated and saturated acids. Latest at excessive consumption disrupt fat metabolism, functioning gastrointestinal tract, increase the possibility of atherosclerosis. Unsaturated acids have the opposite effect: they restore normal metabolism and remove cholesterol. But their abuse leads to indigestion, the appearance of stones in gallbladder and excretory pathways.

Sources

Almost all foods contain fats, but their structure can be different. The exception is vegetables, fruits, alcoholic drinks, honey and some others. Products are divided into:

Also important is fat, which determines the presence of a particular acid. According to this feature, they can be saturated, unsaturated and polyunsaturated. The former are found in meat products, lard, chocolate, ghee, palm, coconut and butter. Unsaturated acids are present in poultry meat, olives, cashews, peanuts, olive oil. Polyunsaturated - in walnuts, almonds, pecans, seeds, fish, as well as in sunflower, flaxseed, canola, corn, cottonseed and soybean oil.

Diet preparation

The structural features of fats require a number of rules to be followed when compiling a diet. Nutritionists recommend adhering to the following ratio:

• Monounsaturated - up to half the total fat;
• Polyunsaturated - a quarter;
• Saturated - a quarter.

In this case, vegetable fats should make up about 40% of the diet, animal fats - 60-70%. Older people need to increase the number of the former to 60%.

Trans fats should be limited as much as possible or completely eliminated from the diet. They are widely used in the production of sauces, mayonnaises, confectionery. Fats that are subjected to intense heating and oxidation are harmful. They can be found in French fries, chips, donuts, pies, etc. Of this entire list, the most dangerous are products that were cooked in rancid or many-used oil.

Useful qualities

Fats, the structure of which provides about half of the body’s total energy, have many beneficial qualities:

• cholesterol promotes better carbohydrate metabolism and ensures the synthesis of vital compounds - under its influence are produced steroid hormones adrenal glands;
• about 30% of all heat in the human body is produced by tissue located in the neck and upper back;
• badger and dog fat are refractory, cure diseases of the respiratory system, including tuberculosis of the lungs;
• phospholipid and glucolipid compounds are part of all tissues, are synthesized in the digestive organs and counteract the formation cholesterol plaques, support liver function;
• Thanks to phosphatides and sterols, the constant composition of the cytoplasmic basis of the cells of the nervous system is maintained and vitamin D is synthesized.

Thus, fats are an essential component in the human diet.

Excess and Deficiency

Fats, the structure and functions of these compounds are beneficial only when moderate consumption. Their excess contributes to the development of obesity - a problem that is relevant for all developed countries. This disease leads to weight gain, decreased mobility and poor health. Increases the risk of developing atherosclerosis, cardiac ischemia, hypertension. Obesity and its consequences lead to death more often than other diseases.

A lack of fat in the diet contributes to the deterioration of the skin, slows down growth and development child's body, disrupts functioning reproductive system, interferes with normal cholesterol metabolism, provoking atherosclerosis, and impairs the functioning of the brain and nervous system as a whole.

Proper diet planning, taking into account the body's fat needs, will help avoid many diseases and improve the quality of life. It is their moderate consumption, without excess or deficiency, that is essential.

It is very difficult to overestimate the role of proteins, carbohydrates and fats for our body.
Each group of products affects our health in one way or another.
Today we will talk about proteins, fats and carbohydrates, and talk about their benefits and the role they play in our body.

General characteristics

Modern humanity, in the frantic pace of life, has completely forgotten about the normal, balanced diet. We are always late at work, work without rest, and perhaps even without lunch break. Therefore, you have to eat quickly, practically without chewing (so that the client does not notice, etc.).
Of course, by practically throwing food into our mouths, we cannot control the amount of food we eat, let alone how much protein, fat or carbohydrates we consume.
Surely you already know that without proteins, no processes can occur, from growth to digestion.
In addition, please note that it is necessary to consume proteins not only of animal origin (at least 55%), but also of plant origin.

Fats: their benefits and functions

If everything is clear about the role of protein, but not so much with fats. It would seem that fats only cause harm and only contribute to weight gain and body fat. But this is far from true. Fat contributes to energy production, and therefore fat metabolism is no less important and beneficial for human body, but it needs to be constantly adjusted.
In the body, all fats are divided into saturated and unsaturated fatty acids. Some of them can be synthesized by the body itself, and have no value. Unsaturated fatty acids are exactly what you should try to exclude from your diet, since they are not only poorly absorbed, but also have a bad effect on your health. fat metabolism.
Such fats are found almost everywhere, especially they are found in semi-finished products and products of industrial origin, and are also found in pork and lamb.
But the complete opposite is unsaturated fats. They have a very high value for the body and can even be safely called vital. The main products in which they can be found are fish oil, sunflower and corn oil.

Carbohydrates: their benefits and functions

Carbohydrates are the most important and most important source of energy that is produced by our body and provides almost 60% of all the body's needs.

Carbohydrates are divided into several types:
Monosaccharides. These include glucose, fructose and galactose. It is this simple carbohydrate that is responsible for the formation of glycogen in our liver, nutrition of muscles and brain, etc.

Disaccharides. These include sucrose, maltose and lactose. Also are simple carbohydrates.

Polysaccharides. These include starch, fiber and glycogen. These are already complex carbohydrates that can completely provide our body with energy, saturation, and are also responsible for the absence of hunger, and practically do not increase blood sugar levels.

It is worth noting that if a deficiency (slight deficiency!) of carbohydrates forms in the body, then all the energy is generated from subcutaneous fat reserves. This principle underlies safe weight loss.

And excessive consumption of carbohydrates contributes to the deposition of all excess in the form subcutaneous fat, accordingly increasing your waist size and weight.

From all this it turns out that his vigor and mood completely depend on the food he consumes, or rather correct ratio all nutrients.

2 Video lecture on the topic: “The role of proteins, fats and carbohydrates in the human body”

Proteins, fats and carbohydrates play an important role in the human body.

Squirrels- complex substances consisting of amino acids. They are an invariable part of the diet. This is the main one construction material, without which the growth of muscles and tissues in general is impossible. Proteins are divided into 2 categories:

AND animalistic, which comes from animal products. This category includes meat, poultry, fish, milk, cottage cheese and eggs.

Vegetable, which the body receives from plants. Here it is worth highlighting rye, oatmeal, walnuts, lentils, beans, soy and seaweed.

Fats - This organic compounds responsible for the “reserve fund” of energy in the body, the main suppliers of energy during periods of food shortage and illness, when the body receives a small amount of nutrients or does not receive them at all. Fats are necessary for the elasticity of blood vessels, due to which useful elements penetrate tissues and cells faster, help normalize the condition of the skin, nail plates and hair. Fats are found in large quantities in nuts, butter, margarine, pork fat, and hard cheese.

Carbohydrates- This main source energy for people. Depending on the number of structural units, carbohydrates are divided into simple and complex. Carbohydrates, called simple or “fast” carbohydrates, are easily absorbed by the body and increase blood sugar levels, which can lead to weight gain. excess weight and deterioration of metabolism.

Complex carbohydrates are made up of many linked saccharides, including tens to hundreds of elements. Such carbohydrates are considered healthy because, when digested in the stomach, they release their energy gradually, providing a stable and long-term feeling of fullness.

Vitamins and microelements that are not included in the structure of tissues also play an important role in the body, but without their participation many vital functions would not be performed. important functions occurring in the human body.

Almost all life processes in our body depend on what we eat. Quite rich in carbohydrates fresh fruits. Must be avoided overuse sweets, flour products, sugar. Balanced diet It has essential– and this implies not only the timely consumption of deliciously prepared food, but also the inclusion in the daily diet of the optimal ratio of substances important for proper functioning such as proteins, fats, carbohydrates, vitamins and microelements. The maintenance of normal life person.

Introduction. 2

I. general characteristics, properties, functions of proteins. 3-5

II. General characteristics, properties, functions of carbohydrates. 5-7

III. General characteristics, properties, use of fats. 8-12

IV. Minerals. 12-18

Conclusion. 19

Bibliography. 20

Introduction.

We know that our food consists of proteins, fats, carbohydrates, minerals, water, and also contains vitamins. Today food preservatives, flavorings and dyes have been created. In this regard, a new branch of chemistry appeared - food chemistry. This section appeared relatively recently, as it was necessary to study food products created genetic engineering, the study of substances created to improve the taste, color and storage of a product. In this essay I will talk about the main components of food, i.e. about the basics of food chemistry - proteins, fats, carbohydrates, minerals, about their importance and complex chemical composition.

I. General characteristics, properties, functions of proteins.

I.I. general characteristics

Squirrels- these are nitrogen-containing high-molecular organic substances with complex composition and the structure of molecules. A protein can be thought of as a complex polymer of amino acids. Proteins are part of all living organisms, but they play a particularly important role in animal organisms, which consist of certain forms of proteins (muscles, integumentary tissues, internal organs, cartilage, blood). Plants synthesize proteins (and their components - amino acids) from carbon dioxide CO2 and water H2O through photosynthesis, assimilating the remaining elements of proteins (nitrogen N, phosphorus P, sulfur S, iron Fe, magnesium Mg) from soluble salts in the soil. Animal organisms mainly receive ready-made amino acids from food and build the proteins of their body on their basis. A number of amino acids (nonessential amino acids) can be synthesized directly by animal organisms. Characteristic feature proteins is their diversity associated with the quantity, properties and methods of combining the amino acids included in their molecule. Proteins act as biocatalysts for enzymes that regulate the speed and direction of chemical reactions in organism. In combination with nucleic acids provide the functions of growth and transmission of hereditary characteristics, are the structural basis of muscles and carry out muscle contraction. Protein molecules contain repeating amide bonds C(0)NH, called peptide bonds (the theory of the Russian biochemist A.Ya. Danilevsky). Thus, a protein is a polypeptide containing hundreds or thousands of amino acid units.

Structure of proteins.

The special character of each type of protein is associated not only with the length, composition and structure of the polypeptide chains included in its molecule, but also with the way these chains are oriented. There are several degrees of organization in the structure of any protein:

1. The primary structure of a protein is a specific sequence of amino acids in a polypeptide chain.

2. The secondary structure of a protein is a method of twisting a polypeptide chain in space (due to a hydrogen bond between the hydrogen of the amide group NH and the carbonyl group CO, which are separated by four amino acid fragments).

3. The tertiary structure of a protein is the actual three-dimensional configuration of a twisted helix of a polypeptide chain in space (a helix twisted into a helix). The tertiary structure of a protein determines the specific biological activity of the protein molecule. The tertiary structure of a protein is maintained through the interaction of various functional groups polypeptide chain: disulfide bridge (-S-S-) between sulfur atoms, ester bridge between carboxyl group (-CO-) and hydroxyl (-OH), salt bridge between carboxyl (-CO-) and amino groups (NH2).

4. Quaternary protein structure is a type of interaction between several polypeptide chains. For example, hemoglobin is a complex of four protein macromolecules.

I . II

Physical properties.

Proteins have a large molecular weight (104107 g/mol), many proteins are soluble in water, but, as a rule, form colloidal solutions, from which they precipitate when the concentration of inorganic salts increases or salts are added heavy metals, organic solvents or by heating (denaturation).

Chemical properties.

1. Denaturation is the destruction of the secondary and tertiary structure of the protein.

2. Qualitative reactions to protein: biuret reaction: violet coloring when treated with copper salts in alkaline environment(all proteins are produced), xanthoprotein reaction: yellow color under the action of concentrated nitric acid, turning into orange under the influence of ammonia (not all proteins are produced), the formation of a black precipitate (containing sulfur) when lead (II) acetate is added, sodium hydroxide and heating. 3. Hydrolysis of proteins when heated in an alkaline or acidic solution with the formation of amino acids.

I . III . Biological functions of proteins.

The multitude of chemical bonds characteristic of protein macromolecules determines their functional diversity.

1. Catalytic – refers to biological catalysts.

2. Transport - performs the functions of transporting substances from one cell compartment to another or between organs of the whole organism.

3. Regulatory – regulatory functions, primarily these include hormones.

4. Protective – represented by antibodies or immunoglobulins.

5. Contractile - allow contraction and movement, usually found in muscle tissue.

6. Structural – part of cell membranes.

7. Receptor - involved in the transmission of a nervous or hormonal signal.

8. Reserve and nutritious – reserve and nutritious material of the cell.

9. Toxic – represented by toxins from the venom of snakes, scorpions, and bees.

Most of all we consume reserve and nutritious proteins (for example, meat, nutritious protein of bird eggs, milk and others).

The most commonly consumed proteins by humans:

Albumins are proteins of animal and plant tissues. They are considered nutritious proteins. Differences between albumins animal cell and vegetable consists of different amounts of methionine and tryptophan. As well as many complex proteins - lipoproteins, glycoproteins, phosphoproteins, chromoproteins.

Fragment of a chromoprotein molecule.

Products with the greatest content protein (per 100g product): dairy products(cottage cheese, cheese), chicken eggs ( I categories), pork, fish, sturgeon caviar, hazelnuts.

II . General characteristics, properties, functions of carbohydrates.

II . I . General characteristics.

Carbohydrates, an important class of natural substances, are found ubiquitously in plant, animal, and bacterial organisms.

Carbohydrates are not a very good term, since this is the name given to a large number of compounds that have different chemical structure and biological functions. More than 100 years ago, it was proposed to use this term to name natural compounds whose composition corresponded to the formula (CH 2 O) n, i.e. carbon hydrates. As new carbohydrates were discovered, it turned out that not all of them correspond to this formula, and some representatives of other classes have the same formula. A great contribution to the development of the study of carbohydrates was made by domestic scientists A.M. Butlerov, A.A. Colley, N.N. Kochetkov.

Carbohydrates include compounds ranging from low molecular weight compounds containing only a few carbon atoms to substances whose molecular weight reaches several millions.

Carbohydrates make up 80% of the dry matter mass of plants and about 2% of the dry matter of animal organisms. Animals and humans are not able to synthesize sugars and obtain them from various food products plant origin. Disaccharides

Sucrose Trehalose

II . II . Physical and chemical properties.

Physical properties.

Monosaccharides are solid substances that can crystallize. They are hydroscopic, very easily soluble in water, and easily form syrups, from which it can be very difficult to isolate them in crystalline form.

Disaccharides are crystalline carbohydrates, the molecules of which are built from the interconnected residues of two monosaccharide molecules.

Polysaccharide molecules can be considered as a product of polycondensation of monosaccharides. The general formula of polysaccharides is (SbH10O5)p. We will look at the most important natural polysaccharides - starch and cellulose.

Chemical properties.

1. Properties characteristic of alcohols :

Reaction with carboxylic acids to form esters (esterification reaction).

2. Properties characteristic of aldehydes : interaction with silver(I) oxide in ammonia solution(reaction of the “silver mirror”).