Biological value of nutrients in milk. Introduction

Nutritional value - the main characteristic of a food product - the amount of nutrients contained in it (proteins, fats, etc.) and their ratio.

Raw materials for milk production are natural milk, skimmed milk, cream.

Natural milk is full fat milk without any additives. It does not enter the sale, as it has a non-standardized fat content and SOMO. It is used to produce various types of milk and dairy products.

Skimmed milk - skimmed part of milk obtained by separation and containing not more than 0.05% fat.

Cream - the fat portion of milk obtained by separation.

Milk is a biologically valuable food product, especially for children. It contains high-grade proteins, fats, phosphatides, fat-soluble vitamins, mineral salts. In total, about 100 biologically important substances have been found in milk.

The chemical composition of milk is as follows: proteins 3.5%, fats 3.4%, milk sugar 4.6%, mineral salts (ash) 0.75%, water 87.8%. The chemical composition of milk varies depending on the breed of animals, the season, the nature of the feed, the age of the animals, the lactation period, and the technology of milk processing.

Milk proteins are readily available for digestive enzymes, and casein has a unique property, forming a glycopolymacropeptide in the process of digestion, to have a regulatory effect on increasing the digestibility of other nutrients.

Milk proteins are represented by casein, albumin and globulin. They are complete and contain all the amino acids necessary for the body. Casein in milk is in the form of caseinogen in a bound state with calcium. When milk souring, calcium is split off from casein, which, coagulating, precipitates.

Milk fat in milk is in the form of tiny fat globules 0.1-10 microns in size. When milk is standing, fat globules rise up due to their low specific gravity, forming a layer of cream. Due to the low melting point (within 28-36°C) and high dispersion, milk fat is digested by 94-96%. As a rule, the fat content of milk in autumn, winter and spring is higher than in summer. It also increases towards the end of the lactation period. In this case, the conditions of keeping the animal and the nature of the feed are of great importance. With good care, the amount of fat in milk can reach 6-7%.

Carbohydrates in milk are in the form of milk sugar, lactose, which is less sweet in taste than vegetable sugar, but its nutritional value is not inferior to it. When boiled, milk sugar caramelizes, giving the milk a brownish color and a specific aroma and taste. Milk sugar is of great importance in the production of lactic acid products. Under the action of lactic acid bacteria, it turns into lactic acid; while curdling the casein. This process is observed in the production of sour cream, curdled milk, cottage cheese, kefir.

The composition of milk includes phosphorus, calcium, potassium, sodium, iron, sulfur. They are found in milk in an easily digestible form, which is especially important in early childhood, when milk is the staple food. Of the trace elements in milk contains zinc, copper, iodine, fluorine, manganese.

The main vitamins of milk are vitamins A and B, some amounts of ascorbic acid, thiamine, riboflavin, nicotinic acid. Their content is subject to significant fluctuations. In summer, when animals eat juicy green fodder, the content of vitamins in milk increases. In winter, due to the transition to dry food, the amount of vitamins in milk decreases. In the future, the content of vitamins depends on the conditions of storage, transportation and processing of milk.

Milk contains a number of enzymes. The main ones are: phosphatase, peroxidase, reductase, amylase, lipase and catalase.

Introduction

Relevance: An important place in the human diet is occupied by milk and dairy products. Milk contains all the nutrients needed by the human body without exception. One of the most distinctive and important properties of milk as a food product is its high biological value and digestibility due to the presence of complete proteins, milk fat, minerals, trace elements and vitamins.

The digestibility of milk and dairy products ranges from 95 to 98%. Milk also aids in the absorption of other foods. Of particular importance for the body are sour-milk products, which have a high dietary and medicinal value.

Along with cow's milk, milk of other animals is used for food: sheep, goats, deer, mares, camels, buffaloes, etc.

Sheep's milk is more than 1.5 times richer in fat and protein than cow's milk. It is used for the production of feta cheese and other types of pickled cheeses.

Goat's milk is used in a mixture with sheep's milk in the production of feta cheese and cheese. Goat milk has more vitamin C and minerals than cow milk.

Mare's milk is a white liquid with a bluish tint. It differs from cow's sweet taste due to the increased content of lactose, contains less fat, salts and proteins. It is used to make koumiss.

Purpose, objectives of the course work- studying the features of the technology for obtaining benign milk.

Nutritional value, composition and properties of cow's milk

Nutritional value of milk

Cow's milk has a high nutritional value, which is due to the optimal content of proteins, fats, carbohydrates, mineral salts and vitamins in it, and the ratio and form in which the components are present in milk contribute to their good digestibility and assimilation. Currently, over 200 different components are known in milk. The main components include water, protein, fat, lactose and minerals (see Table 2).

Milk also contains vitamins, enzymes, hormones, etc. Foreign substances may contain antibiotics, pesticides, detergents, toxic elements, radionuclides, aflatoxins, etc.

The chemical composition of milk, the degree of dispersion of its components determine the chemical and physical properties of milk. The most important properties for milk processing processes are given in Table 5.

Milk and dairy products are characterized energy value, which complements the nutritional value of the product. It can be calculated using the following formula:

E \u003d (37, 7F + 16.7B + 15.9L) * 1,

where E - energy value, kJ; W, B, L - respectively, the mass fraction of the content of fat, protein and lactose in the raw material or product,%; 37.7, 16.7 and 15.9 are coefficients.

Table 5. Chemical and physical properties of cow's milk

At a temperature of 20 °C.

- a complete food product. According to the Nobel Prize winner Academician I.P. Pavlova, "among the varieties of human food, milk is in an exceptional position as food, prepared by nature itself." Easy digestibility is one of the most important properties of milk as a food product. Moreover, milk stimulates the absorption of nutrients from other foods. More than 500 million liters of milk are drunk annually in the world, the consumption of which brings variety to the diet, improves the taste of other products. Milk has therapeutic and prophylactic properties. The main significance of milk in nature is to provide nutrition to the born young organism.

The nutritional and biological value of milk and dairy products is higher than that of other products found in nature. Milk contains more than 120 different components, including 20 amino acids, 64 fatty acids, 40 minerals, 15 vitamins, dozens of enzymes, etc.

When drinking 1 liter of milk, the daily requirement of an adult for fat, calcium, phosphorus is satisfied, 53% for protein, 35% for vitamins A, C and thiamine, 26% for energy. The energy value of 1 liter of raw milk is about 65 kcal.

The nutritional value milk is due to its chemical composition. It differs somewhat for the milk of different species and breeds of animals, may vary depending on the conditions of their feeding.

Squirrels are the most valuable component of milk. They make up about 3.3%, including casein 2.7%, albumin 0.4%, globulin 0.12%. Casein is a complex phosphoprotein and is found in the form of a calcium salt (calcium caseinate), giving the milk a white color. In fresh milk, casein forms a colloidal solution; in an acidic environment, lactic acid splits off calcium from the casein molecule, free caseic acid precipitates and a lactic acid clot is formed.

Casein coagulates under the action of rennet (produced by the glands of the gastric mucosa). After precipitation of casein from skimmed milk, whey proteins and some other components remain in the whey.

According to the content of deficient essential amino acids (lysine, tryptophan, methionine, threonine), whey proteins are the most biologically valuable part of milk proteins, important for food purposes. The main ones - lactoalbumin and lactoglobulin - have a high content of growth and protective substances. In cow's milk, these proteins make up 18% of the total amount of protein, in goat's milk they are 2 times more. When heated above 70 ° C, milk loses part of lactoalbumin and lacto globulin, they denature and precipitate. Therefore, to free milk from microbes, it is subjected to pasteurization at a temperature not exceeding 70 ° C. In addition, the composition of whey proteins includes immunoglobulins (1.9-3.3% of the total amount of proteins) - high-molecular proteins that act as antibodies and suppress foreign proteins by gluing microbes and other foreign cells.

Milk proteins contain all essential amino acids and are complete.

Fat in milk is contained in an amount of 2.8 to 5%. Milk is a natural emulsion of fat in water: the fatty phase is in the milk plasma in the form of small droplets - fat globules, covered with a protective lecithin-protein shell. When the shell is destroyed, free fat forms lumps of fat, which impairs the quality of milk. To ensure the stability of the fat emulsion, it is necessary to minimize the mechanical effects on the dispersed phase of milk during transportation, storage and processing, avoid foaming it, properly conduct heat treatment (long-term exposure at high temperatures can cause denaturation of the structural proteins of the shell of fat globules and damage to its integrity), apply additional dispersion of fat by homogenization.

Milk fat is made up of a complex mixture of acylglycerols (glycerides). Of the several thousand triglycerides of milk fat, most are heteroacid, so the fat has a relatively low melting point and a uniform consistency.

Among saturated acids, palmitic, myristic and stearic acids predominate (60-75%), among unsaturated acids - oleic (about 30%). The content of stearic and oleic acids increases in summer, and that of myristic and palmitic acids in winter. Milk fat contains low molecular weight volatile saturated fatty acids - butyric, caproic, caprylic and capric (4-10%), which determine the specific taste of milk fat. A lower content of low molecular weight acids is a sign of falsification of milk fat by other fats. In addition to oleic acid, there are also small amounts of unsaturated fatty acids - linoleic, linolenic and arachidonic (3-5%).

Unsaturated and low molecular weight fatty acids give milk fat low melting point (melting point - 27-34 ° C). These acids have more valuable biological properties than high-molecular and saturated ones. Low melting point and high dispersion ensure good digestibility of milk fat.

The disadvantages of milk fat include its low resistance to high temperatures, light rays, atmospheric oxygen, water vapor, solutions of alkalis and acids. Rancidity of fat occurs due to hydrolysis, oxidation, salting.

Associated substances in the composition of milk fat are 0.3 - 0.55%. Nasterins account for 0.2-0.4%. They are mainly represented by cholesterol in the free state or in the form of fatty acid esters, as well as ergosterol, etc. Along with simple lipids, milk fat includes a variety of phospholipids (lecithin, cephalin, etc.), which have an emulsifying ability, participate in the construction of ball shells fat. The yellow color of milk fat is due to the presence of carotenoids in it - tetraterpene hydrocarbons (carotenes) and alcohols (xanthophylls). The content of carotenes depends on the feed rations, the condition of the animals and the time of year (more in summer) and is 8-20 mg per 1 kg of milk fat.

Lactose(milk sugar) is the main carbohydrate of milk, monosaccharides (glucose, galactose, etc.) are present in it in smaller quantities, more complex oligosaccharides - in the form of traces.

The disaccharide lactose is the main source of energy for biochemical processes in the body (it accounts for about 30% of the energy value of milk), promotes the absorption of calcium, phosphorus, magnesium, and barium. In milk, lactose is in the free state in the form of a- and p-forms. A very small portion of lactose is associated with other carbohydrates and proteins. Milk sugar slowly penetrates through the intestinal wall into the blood, so it is used for nutrition by lactic acid bacteria, which heal the environment of the stomach. When milk is heated above 95 ° C, the color of milk changes from yellowish to brown due to the formation of melanoidins, which have a dark color, as a result of the reaction of milk carbohydrates with proteins and some free amino acids.

During hydrolysis, lactose is broken down into glucose and galactose, and during fermentation under the influence of enzymes, into acids (lactic, butyric, propionic, acetic), alcohols, esters, gases, etc.

minerals milk contains up to 1%, they contain more than 50 elements. The main ones are calcium, phosphorus, magnesium, potassium, sodium, chlorine and sulfur. Calcium in I liter of milk contains 1.2 g, it is necessary for the formation of bones, regulation of blood pressure. Calcium salts are of great importance not only for humans, but also for milk processing processes. For example, an insufficient amount of calcium salts causes slow rennet coagulation of milk in the manufacture of cheeses, and their excess causes coagulation of milk proteins during sterilization. About 22% of all milk calcium is associated with casein, the rest is salts - phosphates, etc. These compounds contain phosphorus, it is also part of casein, phospholipids, etc.

Magnesium performs the same role as calcium and is found in the same salts.

Sodium and potassium are found in the form of salts (ions), and some of them are associated with casein and shells of fat globules. Salts of potassium and sodium are contained in milk in the ion-molecular state in the form of well-dissociating chlorides, phosphates, citrates (salts of citric acid), etc. Sodium and potassium chlorides provide a certain osmotic blood pressure. Their phosphates and carbonates are part of systems that maintain a constant concentration of hydrogen ions.

trace elements in milk (iron, copper, silicon, selenium, tin, chromium, lead, etc.) are associated with shells of fat globules (Fe, Cu), casein and whey proteins (Fe, Cu, Zn, Mn, Al, I, Sen etc. .), are part of enzymes (Fe, Mo, Mn, Zn), vitamins (Co), hormones (I, Zn, Cu). They provide the construction and activity of vital enzymes, vitamins and hormones necessary for the body's metabolism.

Enzymes are biocatalysts for biochemical reactions. Thus, the production of fermented milk products and cheeses is based on the action of enzymes of the classes of hydrolases, oxidoreductases, granferases, and others. Many lipolytic, proteolytic and other enzymes cause profound changes in the composition of milk during the development and storage of dairy products, which can lead to a decrease in their quality. According to the activity of some enzymes, one can judge the sanitary and hygienic state of raw milk or the effectiveness of its pasteurization. So, depending on the indicator of p-oxidase activity of milk, a conclusion is made about the effectiveness of its high-temperature pasteurization. According to the catalase test, the degree of contamination of pasteurized dairy products with extraneous microflora is judged.

The high sensitivity of alkaline phosphatase to heating is the basis of the method for monitoring the efficiency of pasteurization of milk and cream (phosphorus test). The enzyme glypase catalyzes the hydrolysis of triglycerides in milk fat. In milk, as a result of cooling, redistribution of lipase from proteins to the shell of the fat ball can occur. At the same time, hydrolysis of fat occurs, low molecular weight fatty acids (butyric, caproic, caprylic, etc.) are released, and the milk becomes rancid. Spontaneous rancidity of milk due to hydrolysis of fat under the action of lipase (lipolysis) is characteristic of old and mastitis milk. Lipolysis in ordinary milk is possible after pumping milk, mixing, homogenization, etc. In cheeses such as Roquefort, Camembert lipases of microscopic fungi create a specific taste and aroma as a result of the release of volatile fatty acids during the decomposition of fat.

Hormones present in milk in small amounts; these are thyroxine, prolactin, adrenaline, oxytocin, insulin. Endogenous hormones secreted by the endocrine glands of the animal enter the milk from the blood. Exogenous hormones are residues of hormonal preparations used to stimulate productivity, feed absorption, etc.

gases, dissolved in milk, have a level of 60-80 ml / 1 l in fresh milk. In this volume of carbon dioxide 50-70%, oxygen 5-10%, and nitrogen 20-30%, there is also a certain amount of ammonia. During storage, due to the development of microorganisms, the amount of ammonia increases, and oxygen decreases. An increase in the oxygen content during pumping, transporting milk gives it an oxidized taste. During pasteurization, the content of oxygen and carbon dioxide is reduced.

Foreign chemicals can get into milk as a result of feeding, increased radiation in the area where animals are kept, etc. Substances harmful to humans include impurities of antibiotics, pesticides, heavy metals, nitrates and nitrites, residues of disinfectants, bacterial and plant poisons, and radioactive isotopes. Their content should not exceed the permissible levels established by SanPiN 2.3.2.1078.

Quality shaping factors associated with the processing of milk, which is carried out immediately after milking. It is filtered and cooled to the lowest possible positive temperatures. Timely cooling of milk helps to extend its shelf life.

The milk received at the dairy plant is checked for organoleptic characteristics, acidity and fat content. The received milk is purified from mechanical impurities, then normalized for fat, i.e. reduce or increase the fat content, using skimmed milk (skim) or cream for this.

During the separation and pumping of milk, a partial destabilization of the fat emulsion occurs - the release of free fat on the surface of fat globules, their sticking together and the formation of lumps of fat. To increase the degree of dispersion of the fatty phase, increase its stability, improve the consistency and taste of milk, it is homogenized. To do this, heated milk is sent to homogenizers, where it is passed under high pressure through a narrow slot, as a result of which the fat globules are crushed - their diameter is reduced by 10 times.

Thermal (pasteurization and sterilization) is necessary to destroy microorganisms and destroy enzymes in order to obtain products that are hygienically safe and have a longer shelf life. At the same time, the nutritional and biological value of milk should be preserved to the maximum, and there should be no undesirable changes in its physical and chemical properties.

Pasteurization it can be long-term (at a temperature of 63 ° C, milk is kept for 30 minutes), short-term (at a temperature of 72 ° C for 15-30 minutes) and instant (high-temperature at 85 ° C and above without exposure). In the process of heating, whey proteins are denatured (structural changes in molecules) and the milk acquires the taste of a boiled product or the taste of pasteurization. As a result of pasteurization and sterilization, the amount of calcium in milk decreases due to the formation of poorly soluble calcium phosphate (precipitates in the form of a milk stone or burn along with denatured proteins). This impairs the ability of milk to rennet coagulation; in the production of cottage cheese and cheese, calcium chloride is added to pasteurized milk.

Sterilization milk causes the decomposition of lactose with the formation of carbon dioxide and acids - formic, lactic, acetic, etc. Due to the denaturation of the protein shells of fat balls during sterilization of milk, rendering of fat is observed. Sterilization of milk in bottles consists in processing it in autoclaves under the following conditions: at 104 ° C for 45 minutes; at 109 °C for 30 min; at 120 °C for 20 min. Sterilization of milk in the flow is carried out at ultrasonic temperatures (UT) of 140-142 °C with exposure for 2 s and subsequent cooling and bottling under aseptic conditions. With ultrasonic sterilization, more vitamins are stored in milk than with sterilization in bottles. Most of all, vitamin C is lost (10-30%).

Insufficient heat treatment leads to incomplete inactivation of milk enzymes, which cause undesirable biochemical processes in milk and dairy products. The result can be a reduction in the quality, taste and nutritional value of products. Thus, lipases contribute to the rancidity of dairy products, and proteinases of bacterial origin cause coagulation of the U-milk.

As a result of pasteurization and sterilization, such physicochemical and technological properties of milk as viscosity, surface tension, acidity, ability to settle cream, ability of casein to rennet coagulation change. Milk acquires a specific taste, smell and color, its constituent parts change.

"Milk - this is amazing food prepared by nature itself,” wrote academician I.P. Pavlov. Milk contains in its composition all the nutrients necessary for a person: proteins, fats, carbohydrates, vitamins, minerals, enzymes, hormones, immune bodies. The chemical composition of milk depends on many factors: the quality of the feed, the time of year, the age of the animal, its breed, etc.

The nutritional value. The content of proteins in cow's milk ranges from 2.7 to 3.8%. The main proteins of milk - casein (2.7%), albumin (0.4%), globulin (0.12%) - are complete in amino acid composition. They have a high nutritional value and good digestibility (96%).

Classification and range of drinking milk. By composition, milk is divided into natural: whole (natural, unchanged), normalized for fat content (fat content brought to a certain value), skimmed and reconstituted, which is obtained from whole or skimmed milk powder, often mixed with natural milk. According to the type of heat treatment, milk is classified into pasteurized and sterilized.

There are the following types drinking milk:

- pasteurized(various fat content - 1.5; 2.5; 3.2; 3.5; 6% and non-fat);

- sterilized(various fat content - 0.5; 1.5; 1.8; 2; 2.5; 3.2; 3.5; 3.6; 4; 5.5; 6%). Sterilized milk includes milk obtained using high-temperature technology (HTT or UHT), which involves rapid heating for 4-5 seconds to a temperature of 140 ° C, rapid cooling and aseptic filling (into sterile containers under sterile conditions);

- ghee(with a fat content of 4 and 6%), obtained by long exposure (for 5-6 hours) at a temperature of 95-98°C;

- protein(with a fat content of 1 and 2.5%) - with an increased concentration of proteins due to the addition of skimmed milk powder;

- enriched with fillers: fortified (with vitamin C - 0.05; 2.5; 3.2%; with a complex of vitamins and minerals - of various fat content), with flavorings (chocolate, strawberry, banana, etc. - of various fat content);

- for young children(ionic - milk, close in composition to human milk due to the replacement of calcium and magnesium ions with potassium and sodium ions; vitalact DM, etc.).

Cream differ from milk in the increased content of milk fat. They are obtained by separating milk. Cream is used as a raw material in the manufacture of sour cream and butter, as well as an independent food product. They produce cream pasteurized (10, 20 and 35%), sterilized (10 and 20%), with sugar and flavoring agents (cocoa, coffee, etc.).

Evaluation of the quality of milk and cream. The quality of milk and cream is evaluated by organoleptic, physico-chemical and bacteriological indicators. Organoleptic characteristics include appearance and texture, color, taste and smell. The consistency of milk and cream should be homogeneous, without sediment, for cream - without stray lumps of fat and protein flakes. Color - white with a slightly yellowish or creamy tinge (low-fat milk may have a slightly bluish tinge). Taste and smell - pure, without extraneous smacks and smells.

The main physical and chemical indicators of the quality of milk and cream are the mass fraction of fat (in%, not less), acidity (in Turner degrees, not more), the absence of phosphatase (in pasteurized milk and cream), for milk - density (g / cm 3 , not less), degree of purity. Bacteriological indicators - the total number of microorganisms in 1 ml of milk (cream) and the titer of bacteria of the Escherichia coli group (CGB).

The safety indicators of milk and cream include the content of toxic elements (lead, cadmium, copper, zinc, mercury, arsenic), mycotoxins (aflatoxin M 1), antibiotics, hormonal drugs, pesticides, radionuclides (cesium-134, -137; strontium-90 ), as well as microbiological (sanitary and hygienic) indicators. The indicated safety indicators are common for dairy products.

Terms and conditions of storage. The temperature of milk and cream upon release from the enterprise should be no more than 8°C (pasteurized) and 20°C (sterilized). Pasteurized milk and cream are stored at a temperature not exceeding 8°C for 36 hours from the end of the technological process. Sterilized milk is stored at a temperature not exceeding 20°C from 10 days to 6 months, depending on the type of packaging, sterilization mode and storage temperature, sterilized cream at the same temperature - no more than 30 days.

SRS №3

Working with terms. Use a dictionary to define the terms: hydrolysis, antigen, vitamins, casein, globulin.

Theme 4. Classification of milk and dairy products. Morphology of the scientific style of speech. Morphological features of the scientific style. Work on special vocabulary

Goals. Formation of ideas about the morphological features of the scientific style.

Tasks. Development of skills in the use of complex nouns, verb-nominal phrases, participles in the preparation of a coherent statement.

SRSP. Discussion on the topic: "Natural products and their substitutes: advantages and disadvantages."

SRS. Compiling a table « Classification and assortment of milk.

The nutritional value of milk and products prepared on its basis determines its importance in children's and dietary nutrition. By including such foods in your diet, you will saturate the body with calcium and other valuable substances. Milk makes a person healthier and more beautiful.

What is nutritional value?

If you are interested in certain characteristics of products, you should know for sure what they mean. Thus, nutritional value is a complete list of properties that satisfy the physiological needs of the body. Most often, this concept means the content of proteins, fats and carbohydrates in every 100 grams of products.

It is also worth noting the importance of such an indicator as biological value. It characterizes the compliance of the amino acid needs of the human body. Speaking of energy value, it is worth noting that this is the number of calories that are released during the processing of the product by the body.

Milk: chemical composition and nutritional value

Milk is the first human food, which gives the body everything it needs from birth. Due to the rich chemical composition, it is possible to maintain the active vital activity of the body. So, milk contains the following substances:

• proteins;
• fats;
• milk sugar;
• mineral salts;
• water.

It should be noted that this is a basic set of components that cannot fully characterize milk. The chemical composition and nutritional value can vary greatly, depending on the origin of the product, as well as the way it is processed.

If we consider in more detail the proteins contained in milk, they are represented by albumin, globulin and casein. The latter is involved in the formation of glycopolymacropeptide, which increases the absorption of other components. All proteins are characterized by easy absorption and contain all the amino acids necessary for the body.

Fats in milk are contained in the form of tiny particles. It is they who form everyone's favorite cream. Milk fat is 96% absorbed by the body, due to its high dispersion. Its content in the product depends on the season (in summer this figure decreases), as well as the quality of animal care.

Considering such an indicator as the nutritional, energy value of milk, one cannot fail to mention the carbohydrate component. It is represented by lactose. It is the presence of this component that determines the possibility of preparing fermented milk products.

The nutritional value of milk is determined by the high content of vitamins. The main ones are A and B. Ascorbic acid, nicotinic acid, riboflavin and thiamine are present in a small amount. The highest concentration of vitamins in milk is observed in the summer. Also, this indicator can be affected by the method of processing and storage conditions.

More about vitamins

As already mentioned, the nutritional value of milk and dairy products is largely due to the increased content of vitamins in them. So, if we take a closer look at the chemical composition, we can note the presence of the following useful components in it:

Different types of milk

The nutritional value of milk is largely determined by its origin. So, deer is considered the most nutritious. The concentration of proteins and fats reaches, respectively, 11% and 20%. As for the vitamin component, it is three times more saturated than in the case of cow's milk.

The nutritional value of milk is largely determined by the nature of the proteins that it contains. So, most farm animals (including cows and goats) give casein milk. And, for example, mare and donkey is albumin. Since it is most similar in composition to mother's milk, such milk is an ideal substitute for breastfeeding. Albumin particles are several times smaller than casein, and therefore we can talk about its good digestibility.

Whole milk

Despite the fact that milk is one of the most common products that has been known since childhood, not everyone thinks that there are several types that are characterized by certain indicators. So, for starters, you should pay attention to whole milk. The nutritional value, in this case, will be the highest, because the product has not been subjected to any processing. An exception may be the straining process, which is carried out immediately after milking.

Whole milk contains the highest amount of vitamins and minerals. There is also a high concentration of calcium, which is almost completely absorbed by the body. This product is credited with strengthening the immune system, normalizing the functioning of the nervous system, eliminating heartburn, accelerating metabolism.

However, there are a number of skeptical claims about whole milk. Given its high fat content, it is not suitable for feeding children. And in adulthood, not everyone tolerates this product well. So, according to the latest data, one sixth of the world's population suffers from lactose intolerance. Whole milk is an allergen, and can also cause dangerous infections.

Skimmed milk

The desire for harmony makes people buy products marked "0% fat". This trend has also affected milk. The amount of fat in it does not exceed 0.1%. In fact, this is the so-called reverse, which is obtained by separating cream from milk. It should be interesting to buyers that most of this milk is not sent to store shelves, but back to farms to feed animals.

Do not place high hopes on a product such as skimmed milk. Its nutritional value is negligible. Carbohydrates and proteins, respectively, 5% and 3%. Calorie content is characterized by an indicator of 35 kcal. At the same time, such milk is characterized by a rich vitamin and mineral composition. Nevertheless, doctors do not recommend using it on an ongoing basis.

It is worth paying attention to the manufacturing process. The nutritional value of powdered, skimmed milk is significantly reduced during processing. When the fat component is removed, vitamins A and D are almost completely removed from the product. Thus, the proteins and calcium that remain in the milk are not absorbed by the body. With the frequent use of skimmed and powdered milk, the body's own resources are depleted.

Powdered milk: nutritional value

In a big city, it is not always possible to find a natural product. In addition, people tend to give known substances a more convenient form, such as powder. Powdered milk is a good example. The nutritional value of this product is the same as that of the original. But for this you need to prepare the so-called reconstituted milk. To do this, the powder is diluted in water (1: 7). At the same time, it is quite possible to prepare homemade kefir, cottage cheese and other healthy products from such milk.

The nutritional and biological value of milk is preserved thanks to a special manufacturing technology. Fast drying is carried out, and the temperature does not exceed 40 degrees. Thus, all useful substances are preserved. And due to the reduced moisture content (no more than 6%), long-term storage of the product is ensured.

Nutritional value of condensed milk

It is worth admitting that few people are interested in such a question as nutritional value. For most people, this is a favorite delicacy. Nevertheless, condensed milk is not only tasty, but also a very useful product. To begin with, it is worth noting the high protein content in this product. Its concentration can reach 35%.

In fact, condensed milk is evaporated cow's milk. The nutritional value of the final product is slightly lower, but in general it is no less useful. Condensed milk is completely absorbed by the body, saturating it with calcium and phosphorus. Thus, by regularly consuming this product, you can strengthen the health of bones, eyes and enhance mental activity.

However, condensed milk should not be abused. The fact is that it contains a significant amount of sugar, which leads to a high calorie content (328 kcal) and a significant carbohydrate component (55.5 g). A large amount of the product contributes to the development of obesity, diabetes and caries.

Dairy products

The composition and nutritional value of milk make this product one of the most popular. However, in its pure form, few people love it. Most people prefer dairy products. They not only retain the benefits of milk, but also have a beneficial effect on the digestive system. So, you should especially pay attention to the following products:

• Kefir is made from pasteurized milk. A special leaven is added to it, after which the fermentation process begins. The nutritional value of this product depends entirely on the quality of the milk. If a whole product is used, then the protein component accounts for almost 3%, the fat concentration is 3%, and carbohydrates 4%.
• prepared from a pasteurized product using bacterial cultures. It will contain approximately equal amounts of fat and carbohydrates (about 3%) and 10% carbohydrates. Given the low acidity of the product, it is actively used in artificial feeding of children.
• Belakt is also a fermented milk product produced using bacteria. It has a high content of enzymes. Another feature of the product is the presence in the composition of substances that, in their properties, resemble antibiotics.
• "Narine" is a fermented milk product that came to us from Armenia. There it is actively used for breastfeeding. Due to the special bacteria contained in the sourdough, the acidity index is quite low. And, getting into the body, "Narine" activates the production of a substance that suppresses pathogenic microbes. Proteins and fats in the product account for 3% and 4%, respectively, and carbohydrates - just over 6%.
• Koumiss is traditionally made from mare's milk. Nevertheless, recipes adapted for cow's are known. In milk, starter is added, which contains bacteria and yeast. The nutritional value largely depends on the quality of the base and the degree of maturity. It can contain up to 3% protein, up to 1% fat and 6% carbohydrates. The product is useful for digestion, and also has a tonic effect.
• Yogurt is not just a popular fermented milk product, but also a delicacy loved by everyone. In ancient times, it was prepared exclusively from To get yogurt, you need to add the so-called Bulgarian stick to the base. On average, the calorie content of the finished product is characterized by an indicator of 57 kcal. Proteins, fats and carbohydrates it contains, respectively, 4%, 2% and 6%. These figures may vary, depending on the type of milk and the method of processing. It is worth noting that only pure yogurt, which does not contain dyes and flavoring additives, has exceptional benefits.

Other popular products

Since ancient times, people have been interested in such a question as the nutritional value of milk. A great variety of dairy products are prepared on its basis. Nevertheless, there are a number of popular ones that are almost always present on the table, namely:

• Cottage cheese is one of the most valuable food products, which is characterized by a high protein content (about 14%). Its preparation is based on processes. Curd is characterized by high acidity. But this indicator decreases with an increase in the level of fat content of the product.
• The process of making cheese is based on the precipitation of casein. Depending on how the milk is processed, the product can be hard, soft, brine or melted. The protein component can reach 30% (as well as fat).
• Sour cream is a product made from pasteurized cream. It is quite fatty (this figure can reach 40%).

Milk quality

The high nutritional value of milk proteins determines the popularity of this product. Nevertheless, only what is of high quality is useful for the body. The characteristics of milk largely depend on how the processing was carried out.

The milk that entered the plant is first of all checked by organoleptic index. If it turned out to be in accordance with the standards, it is carefully filtered to remove impurities. Next, the fat content is normalized by adding skim milk or cream.

The most important are the stages of pasteurization and sterilization. These processes are necessary for the destruction of pathogens, as well as a number of enzymes. Thus, it is possible to obtain a safe product, which is characterized by long-term storage.

Pasteurization is carried out by prolonged heating. As a result, milk changes its natural taste. It is also worth noting the decrease in the concentration of calcium in the product.

Is milk dangerous for humans?

The nutritional and biological value of milk makes this product one of the most useful. Nevertheless, it is worth mentioning the danger that it carries. Milk can serve as a source of dangerous infectious diseases. In this case, viruses can get into the product from the animal and during processing.

Viruses can be found not only in milk, but also in products prepared on its basis. This increases the incubation period of the bacteria. So, the most dangerous diseases transmitted through milk are the following:

• Foot and mouth disease is a viral disease that affects the mucous membranes and respiratory tract. It appears in the form of blisters and ulcers. The virus of this disease is resistant to heat. To get rid of it, you need to boil the milk for at least 5 minutes.
• Brucellosis is a disease that affects almost all body systems. Its danger lies in the fact that at the initial stage it is almost asymptomatic. Milk from animals infected with brucellosis is subjected to prolonged boiling followed by pasteurization.
• Tuberculosis - affects mainly the respiratory system. If such an infection is found in an animal, then milk is strictly forbidden to be eaten.
• Other dangerous infections are anthrax, rabies, hepatitis, plague, and others. Animals with such diseases are subject to destruction with the obligatory presence of a sanitary doctor.

Conclusion

From the very first days of a person's life, it is milk that supplies the body with all the necessary nutrients and vitamins. Thus, the benefits of this product are undeniable. To maintain bones, digestive, nervous and other body systems in optimal condition, milk simply must be present in the diet. It is important to choose a quality product, and treat it whole or fat-free with caution.

At the moment, there is a wide range of dairy products on the market, which are also characterized by high nutritional value. Among them, you can often find many copies marked "Farm" or "Rustic". Contrary to fashion trends, such products should be treated with extreme caution, because milk that has not been subjected to heat treatment and pasteurization may contain viruses that are dangerous to humans.