Carbohydrates - an integral component of the cells and tissues of any living organism, whether it be a plant, animal, or person. They make up the bulk of the organic matter of planet Earth. Carbohydrates are a fairly extensive class of compounds. Among them, one can find substances of various properties. Due to this feature, the functions of carbohydrates are very wide. Today we will analyze the main properties, physiological role and use of carbohydrates in different areas of the food (and not only) industry.
Carbohydrate sources
The main sources of carbohydrates are products of plant origin. Namely: bread, cereals, vegetables, fruits, berries. As for products of animal origin, some of them are also rich in carbohydrates. This is, first of all, milk, which contains the so-called milk sugar.
Foods may contain different carbohydrates. Therefore, the importance, application of carbohydrates and their functions are very extensive. There is starch in cereals and potatoes - a complex carbohydrate insoluble in water, which is broken down into simple sugars by the action of digestive juices. In fruits, vegetables and berries, these substances are presented in the form of simple sugars: fruit, beetroot, cane, grape and so on. They dissolve in water and are perfectly absorbed by the body. Water-soluble sugars are quickly absorbed into the blood.
Carbohydrate intake
It is believed that the bulk of carbohydrates should be consumed in complex form, and only 20-25% in simple form. This contributes to the gradual flow of sugars into the tissues. If a person receives a sufficient amount of carbohydrates from food, they are deposited in the liver and muscles in the form of "animal starch" of glycogen. With a lack of carbohydrates, the supply of glycogen is broken down into glucose and used for the needs of the body (nutrition of cells and tissues). If the body receives their excess, they pass into body fat. By the way, fiber also belongs to carbohydrates, which is necessary for proper digestion.
Carbohydrates are the essential components of the diet, so they not only determine the energy homeostat of the body, but also participate in the biosynthesis of a number of carbon-containing polymers. For a lifetime, a person consumes on average about 14 tons of these compounds. Of these, approximately 2.5 tons are in simple form. The use of proteins, fats, carbohydrates and their derivatives in food products is not uniform. Carbohydrates are a major part of our diet. They consume 4 times more than protein or fat. With a simple, mixed diet, about 60% of the energy a person receives from carbohydrates. Their main task in the body is to give energy. The more physical activity in a person’s life, the more carbohydrates he needs. With a sedentary lifestyle, the need for these substances decreases. For those who are not engaged in physical labor, the daily need for carbohydrates is approximately 400 grams.
About 50-65% of carbohydrates enter our body with cereal products. 15-25% - with sugar and sugar-containing products. About 10% - with root and tubers. And about 5-7% - with fruits and vegetables.
Carbohydrates are a very strong irritant of the external secretion of the pancreas and the most active stimulator of insulin synthesis, which plays an important role in regulating carbohydrate metabolism and maintaining optimal glucose homeostasis. Overload with simple carbohydrates over the years leads to hyperplasia of β-cells, then to weakening of the insular apparatus and the creation of prerequisites for the development of diabetes mellitus.
Carbohydrate classification
Depending on the structure, ability to dissolve and the rate of assimilation, carbohydrates in food are divided into simple and complex. Monosaccharides (fructose, glucose, galactose) and disaccharides (sucrose, lactose) are considered simple. To complex ones are polysaccharides (fiber, starch, glycogen). In addition to the carbohydrates given as an example, in each of the classes there are other, less well-known substances.
Simple carbohydrates
Mono- and disaccharides dissolve well in water and are quickly absorbed by the body. They have a pronounced sweet taste, so they are often called simply sugars. The most common monosaccharide is glucose, which is found in various fruits and berries, and is also synthesized by the breakdown of di- and polysaccharides. Glucose, once in the body, quickly finds use. It forms glycogen, nourishes brain tissue and muscles (including the heart), and also regulates blood sugar. During exercise, glucose can be used directly as an energy source.
Fructose has similar properties. It can be considered as a very valuable, easily digestible carbohydrate. But, compared with glucose, fructose is still more slowly absorbed by the intestines, and, once in the blood, leaves the bloodstream faster. Up to 80% of fructose is retained in the liver, preventing the supersaturation of blood with sugar. However, in the liver, fructose synthesizes glycogen more easily than glucose. Compared to sucrose, fructose is better absorbed and has a greater sweetness. Due to the latter property, a lower amount of fructose can be used for the required level of sweetness of the product, thereby reducing the total sugar intake. This takes place in the construction of a diet of limited calorie content. When considering the use of carbohydrates in life, special attention should be paid to dietary nutrition. Fructose is often used as a sweetener in the manufacture of products for people with diabetes.
With an excess of sucrose, fat metabolism is disrupted and fat formation increases. In addition, it has long been proven that with an increase in the amount of sugar entering the body, the synthesis of fats from complex carbohydrates, directly fat and even protein, is enhanced. Consequently, the amount of sugar consumed by humans can greatly regulate fat metabolism.
With heavy consumption of sugar, cholesterol metabolism disorders and an increase in its blood content begin. In addition, excess sugar affects the work of the intestinal microflora badly - the mass of putrefactive microorganisms increases, putrefactive processes accelerate, and flatulence develops. Least of all these side effects are observed with the use of fructose. The main source of this carbohydrate is fruits and berries. A lot of fructose and glucose is found in honey: 37.1 and 36.2%, respectively. All sugar that is in the watermelon is fructose, it is about 8% here.
The next monosaccharide is galactose. It is not found in foods in its free form. Galactose is a breakdown product of lactose, the main carbohydrate in milk.
As for disaccharides, the main one in our diet is sucrose. During hydrolysis, it is broken down into fructose and glucose. The main sources of sucrose are beet and cane sugar. In sugar, the content of this carbohydrate reaches 99.75%. In addition, sucrose is found in fruits, vegetables and melons.
Complex carbohydrates
Polysaccharides are characterized by a more complex molecular structure and extremely weak solubility in water. This class includes: starch, fiber, glycogen and pectin. The use of carbohydrates of this class is common to varying degrees. The main nutritional value is starch. Its high content in cereals is the main factor determining their nutritional value. In the average human diet, starch occupies up to 80% of the total amount of carbohydrates consumed. Once in the body, it turns into simple carbohydrates and performs their functions.
As for glycogen, in our body it plays the role of energy material that nourishes working muscles and internal organs. Glycogen is restored through rheosynthesis due to glucose.
Pectin is a soluble substance that is well absorbed in the body. As modern studies in the field of healthy nutrition show, pectin can be used for prophylactic and therapeutic purposes in diseases of the gastrointestinal tract.
Fiber is very similar in structure to polysaccharides. Its high content is famous for cereal products. In addition to the amount of fiber in the product, its quality is of great importance. The more tender this carbohydrate, the better it breaks down in the intestines, and the more benefits it brings to a person. Fiber of vegetables and potatoes possesses these properties. An important feature of this polysaccharide is the ability to remove cholesterol from the human body. Now we will consider in more detail the use of carbohydrates.
Parenteral nutrition
The use of carbohydrates in medicine is rapidly developing today. Parenteral nutrition is the intravenous administration of nutrients to the body. Used in cases where the patient is not able to eat independently. The use of carbohydrates in parenteral nutrition is very common. They are used for the simple reason that they are the most affordable source of energy for the human body. The energy value of carbohydrates is 4 kcal / g. The daily human need for energy ranges from 1.5 to 2 thousand kilocalories. Hence the problem of the isolated use of carbohydrates to meet this need. In terms of an isotonic glucose solution, to fully cover the calorie needs of a person, it is necessary to transfer from 7 to 10 liters of solution. This can lead to the development of hyperhydration, pulmonary edema and cardiovascular disorders.
The use of more concentrated glucose solutions is fraught with other unpleasant consequences - the occurrence of plasma hyperosmolarity and irritation of the veins intima (development of phlebitis and thrombophlebitis). And in order to eliminate the risk of osmotic diuresis, it is necessary to maintain the glucose infusion rate in the range from 0.4 to 0.5 g / kg / h. If you translate this indicator into an isotonic glucose solution, you get a little more than 500 mm per hour for a patient weighing 70 kg. To prevent a violation of tolerance to carbohydrates and the ensuing complications, insulin is added to the glucose solution. The calculation is carried out according to the formula: 1 ED per 3-4 grams of dry glucose. Insulin not only positively affects glucose utilization, but also contributes to the normal absorption of amino acids.
The use of carbohydrates in medicine depends on their type. In parenteral nutrition are widely used: fructose, glucose, sorbitol, dextran, glycerol and ethyl alcohol.
Diet food
There are many diets that are based on the complete or partial elimination of carbohydrates from the diet, as well as an increase in the intake of proteins and fats. The US Department of Agriculture conducted a survey according to which it was found that people who eat carbohydrate-rich foods predominantly have normal weight. Foods that are high in carbohydrates are more nutritious, but less caloric.
As you know, in America, more than half of the population is overweight. Moreover, the number of such people is steadily growing. A long survey of the population on the subject of food consumed showed that people whose carbohydrates predominate receive less calories than protein and fat lovers with the same amount of food eaten. This group of people from all respondents, and there were more than 10,000 people, had the lowest body mass index. The reason is that for 1000 calories of carbohydrate-containing foods, there is a lot of fiber and water. This group of people received with food a greater amount of nutrients, namely: vitamins A and C, carotene, calcium, iron and magnesium. Fats, cholesterol, zinc, sodium and vitamin B12, were insignificantly contained in their diet.
The use of carbohydrates and fats in foods is closely related. However, as is the use of carbohydrates with proteins. The high efficiency of carbohydrates as energy sources lies in their ability to save protein. When a large amount of carbohydrates gets into food, the body uses less amino acids as an energy material. In general, these substances are not indispensable components of nutrition, since they can be synthesized from amino acids and glycerol, however, their role cannot be underestimated. The use of carbohydrates in food should be at least 50 grams per day. Otherwise, metabolic disturbances may occur.
However, excessive intake of carbohydrates leads to the formation of subcutaneous fat. When building a diet, it is important not only to satisfy a person’s need for these substances, but also to balance the consumption of their various types. It is important to monitor the ratio of simple to complex carbohydrates. When a lot of sugars enter the body, they cannot be fully synthesized into glycogen and pass into triglycerides, which contribute to the formation of fatty tissues. When the blood contains insulin levels, this process is accelerated.
Complex carbohydrates, unlike simple ones, are broken down slowly, so their content in the blood increases gradually. In this regard, it is advisable that the main carbohydrate part in food products was composed of difficult to assimilate substances. Their share should be from 80 to 90 percent. The lack of complex carbohydrates is especially noticeable for those who suffer from diabetes mellitus, obesity, atherosclerosis and diseases of the cardiovascular system.
As you already understood, carbohydrates are most used in nutrition and medicine. But this does not end the scope of carbohydrates. Where else do they use them?
Glucose
This carbohydrate is well absorbed by the body and can be used as part of some medications. In addition, glucose is widely used in the confectionery industry. With its help make marmalade, caramel, gingerbread and other products. In the textile industry, it plays the role of a reducing agent. And in the production of glyconic and ascorbic acids, glucose is the initial product. It also synthesizes some industrial sugars.
Of great importance is the fermentation of glucose. It occurs during the pickling of cabbage, cucumbers, milk and other products, as well as during the silage of feed. In the production of beer, alcoholic fermentation of glucose is used.
Starch
Starch is a valuable nutrient. To make it easier for the body to absorb, the products are subjected to heat treatment. Under high temperature conditions, partial starch hydrolysis occurs, as well as the formation of water-soluble dextrins. Dextrins, once in the digestive tract, are hydrolyzed to glucose, which is well absorbed by the body. If we talk about the use of carbohydrates in industry, you can not ignore starch. The main products that are derived from it are glucose and molasses. This further expands the area in which the use of carbohydrates takes place. Briefly describe the process of obtaining glucose and molasses from starch can be as follows.
Starch is heated in a mixture with dilute sulfuric acid. Excess acid is neutralized with chalk. The precipitate of calcium sulfate, which is formed during neutralization, is filtered off. Then the solution is evaporated and glucose is isolated from it. If you do not finish the process of hydrolysis, you get a mixture of glucose with dextrins, which is called molasses. It is used in the confectionery industry. In addition, starch-derived dextrins are widely used as adhesives and thickeners for paints. Starch proves how diverse carbohydrates can be. The chemistry of the processes, however, is not at all complicated.
Previously, starched linen was used, which allows you to breathe a second life into the fabric and extend its service life. Starch and products derived from it have also found application in the textile, pharmaceutical and foundry industries.
Cellulose
The practical benefits of carbohydrates have always been no less important than their biological role. The use of carbohydrates can be found in completely different areas of human activity. Cellulose (fiber) has been used by humans since ancient times. At first, man began to use wood as a fuel and building material. Then from cotton, flax and other fibrous plants learned to make a thread. Later, technologies appeared that made it possible to obtain paper from wood. Paper, in its essence, is a thin layer of fiber fibers that are compressed and sized. The result is a sturdy, smooth surface over which ink does not spread.
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Sometimes carbohydrates are confused with hydrocarbons. Despite the fact that these two classes of substances are consonantly called, they have nothing to do with each other. The use of saturated hydrocarbons in everyday life and in production is a completely different story.
Conclusion
Today, you and you have deepened your knowledge about substances such as carbohydrates. Properties, the use of carbohydrates and their benefits for humans confirm that these substances are the most important biological components on our planet. They are literally everywhere and in everything. But this is not the main thing, but the fact that without carbohydrates our life would be impossible. The use of carbohydrates in life is too extensive.