Carbohydrates for diabetes
Sugars (saccharides, carbohydrates) are organic compounds widespread in nature. They are derivatives of polyhydric alcohols. According to the size and structure of the molecules, they are divided into two groups: simple sugars (monosaccharides) and complex ones (these include disaccharides and polysaccharides).
By the presence of characteristic functional groups, in addition to polyatomic (hydroxyl) groups, which are part of all saccharides, they are distinguished: aldoses - having aldehyde groups, and - having ketone groups.
Read more about the different types of carbohydrates below in the articles I have collected on this topic.
Carbohydrates are organic compounds, most often of natural origin, consisting only of carbon, hydrogen and oxygen. Carbohydrates play a huge role in the life of all living organisms. This class of organic compounds got its name because the first carbohydrates studied by man had a general formula of the form Cx (H2O) y.
Those. they were conventionally considered compounds of carbon and water. However, later it turned out that the composition of some carbohydrates deviates from this formula. For example, a carbohydrate such as deoxyribose has the formula C5H10O4. At the same time, there are some compounds that formally correspond to the formula Cx (H2O) y, but are not related to carbohydrates, such as formaldehyde (CH2O) and acetic acid (C2H4O2).
Nevertheless, the term "carbohydrates" has historically been assigned to this class of compounds, and therefore is widely used in our time.
Classification of carbohydrates
Depending on the ability of carbohydrates to be split during hydrolysis into other carbohydrates with a lower molecular weight, they are divided into simple (monosaccharides) and complex (disaccharides, oligosaccharides, polysaccharides). As you might guess, from simple carbohydrates, i.e. monosaccharides, it is impossible to obtain carbohydrates with an even lower molecular weight by hydrolysis.
During the hydrolysis of one molecule of a disaccharide, two molecules of a monosaccharide are formed, and with the complete hydrolysis of one molecule of any polysaccharide, many molecules of monosaccharides are obtained.
Chemical properties of monosaccharides by the example of glucose and fructose
As you can see, both the glucose molecule and the molecule contain 5 hydroxyl groups, and therefore they can be considered polyhydric alcohols. The glucose molecule contains an aldehyde group, i.e. in fact, glucose is a polyhydric aldehyde alcohol. In the case of fructose, a ketone group can be found in its molecule, i.e. fructose is a polyatomic keto alcohol.
Chemical properties of glucose and fructose as carbonyl compounds
All monosaccharides can react in the presence of catalysts with hydrogen. In this case, the carbonyl group is reduced to an alcoholic hydroxyl group. The glucose molecule contains an aldehyde group in its composition, and therefore it is logical to assume that its aqueous solutions give qualitative reactions to aldehydes.
Attention!
Indeed, when heating an aqueous solution of glucose with freshly precipitated copper (II) hydroxide, as in the case of any other aldehyde, a brick-red precipitate of copper (I) oxide precipitates from the solution. In this case, the aldehyde group of glucose is oxidized to carboxyl - gluconic acid is formed. Also, glucose enters into the "silver mirror" reaction when it is exposed to an ammonia solution of silver oxide.
However, unlike the previous reaction, instead of gluconic acid, its salt is formed - ammonium gluconate, because dissolved ammonia is present in the solution. Fructose and other monosaccharides, which are polyatomic ketalcohols, do not enter into qualitative reactions to aldehydes.
Chemical properties of glucose and fructose as polyhydric alcohols
Since monosaccharides, including glucose and fructose, have several hydroxyl groups in their molecules. All of them give a qualitative reaction to polyhydric alcohols. In particular, freshly precipitated copper (II) hydroxide dissolves in aqueous solutions of monosaccharides. In this case, instead of the blue precipitate of Cu (OH) 2, a dark blue solution of complex copper compounds is formed.
Disaccharides. Chemical properties
Disaccharides are carbohydrates, the molecules of which consist of two monosaccharide residues linked by the condensation of two hemiacetal hydroxyls or one alcoholic hydroxyl and one hemiacetal hydroxyl. The bonds formed in this way between the residues of monosaccharides are called glycosidic. The formula for most disaccharides can be written as C12H22O11.
The most common disaccharide is the familiar sugar chemists call sucrose. The molecule of this carbohydrate is formed by cyclic residues of one glucose molecule and one fructose molecule. The bond between disaccharide residues in this case is realized due to the elimination of water from two hemiacetal hydroxyls.
Since the bond between the monosaccharide residues is formed by the condensation of two acetal hydroxyls, it is impossible for the sugar molecule to open any of the rings, i.e. transition to the carbonyl form is impossible. In this regard, sucrose is not capable of producing qualitative reactions to aldehydes.
Disaccharides of this kind, which do not give qualitative reactions to aldehydes, are called non-reducing sugars. However, there are disaccharides that give qualitative responses to the aldehyde group. This situation is possible when a hemiacetal hydroxyl from the aldehyde group of one of the original monosaccharide molecules remains in the disaccharide molecule.
In particular, maltose reacts with an ammoniacal solution of silver oxide, as well as copper (II) hydroxide, like aldehydes.
Disaccharides as polyhydric alcohols
Disaccharides, being polyhydric alcohols, give an appropriate qualitative reaction with copper (II) hydroxide, i.e. when their aqueous solution is added to the freshly precipitated copper (II) hydroxide, the water-insoluble blue precipitate Cu (OH) 2 dissolves to form a dark blue solution.
Polysaccharides. Starch and cellulose
Polysaccharides are complex carbohydrates whose molecules consist of a large number of monosaccharide residues linked by glycosidic bonds. There is another definition of polysaccharides. Polysaccharides are complex carbohydrates, the molecules of which, upon complete hydrolysis, form a large number of monosaccharide molecules.
In general, the formula for polysaccharides can be written as (C6H11O5) n. Starch is a substance that is a white amorphous powder, insoluble in cold water and partially soluble in hot water to form a colloidal solution, called starch paste in everyday life.
Starch is formed from carbon dioxide and water during photosynthesis in the green parts of plants under the influence of the energy of sunlight. The largest quantities of starch are found in potato tubers, wheat, rice and corn grains. For this reason, these sources of starch are the raw material for its production in industry.
Cellulose is a substance that in its pure state is a white powder, insoluble in either cold or hot water. Unlike starch, cellulose does not form a paste. Filter paper, cotton wool, poplar fluff are practically pure cellulose.
Both starch and cellulose are plant products. However, the roles they play in plant life are different. Cellulose is mainly a building material, in particular, it mainly forms the membranes of plant cells. Starch, on the other hand, has mainly a storage, energy function.
Source: https://scienceforyou.ru/teorija-dlja-podgotovki-k-egje/uglevody
Types of carbohydrates
There are three main types of carbohydrates:
- Simple (fast) carbohydrates or sugars: mono- and disaccharides
- Complex (slow) carbohydrates: oligo- and polysaccharides
- Indigestible, or fibrous, carbohydrates are defined as dietary fiber.
Sahara
There are two types of sugars:
- Monosaccharides - Monosaccharides contain one sugar group such as glucose, fructose or galactose.
- disaccharides - disaccharides are formed by the remains of two monosaccharides and are represented, in particular, by sucrose (common table sugar) and lactose.
Complex carbohydrates
Polysaccharides are carbohydrates containing three or more molecules of simple carbohydrates. This type of carbohydrate includes, in particular, dextrins, starches, glycogens and celluloses. Sources of polysaccharides are cereals, legumes, potatoes and other vegetables.
Source: http://sportwiki.to/%D0%92%D0%B8%D0%B4%D1%8B_%D1%83%D0%B3%D0%BB%D0%B5%D0%B2%D0%BE % D0% B4% D0% BE% D0% B2
Carbohydrates, monosaccharides, polysaccharides, maltose, glucose, fructose
Carbohydrates
Carbohydrates are a large group of organic compounds that play an important role in the life of the body. Carbohydrates are widespread mainly in the plant kingdom. The human body needs 400-500 g of carbohydrates per day (including at least 80 g of sugars). They are an important source of energy.
The digestibility of carbohydrates contained in fruits is 90%; in and dairy products - 98; in table sugar - 99%. Examples of carbohydrates are glucose (C6H2O6), or grape sugar, so named because of its high content in; cane or beet sugar (C6H22011); starch and cellulose (SbN10O5).
These substances are composed of carbon, hydrogen and oxygen. Moreover, the ratio of the last two elements is the same as in water, that is, there is one oxygen atom for two hydrogen atoms. Thus, carbohydrates are, as it were, built from carbon and water, hence their name. Carbohydrates are divided into monosaccharides (eg glucose) and polysaccharides.
Polysaccharides, in turn, are divided into low molecular weight, or oligosaccharides (their representative is beet sugar), and high molecular weight, for example, starch - small and cellulose. Polysaccharide molecules are built from the remains of monosaccharide molecules and are split into simpler carbohydrates during hydrolysis.
Monosaccharides
Of the monosaccharides, the most important for the human body are glucose, fructose, galactose, etc. All of them are crystalline substances, soluble in water. Free glucose is found in the fruits of many plants. In a bound state, it is found in plants in the form of polysaccharides (sucrose, maltose, starch, dextrin, cellulose, etc.). In industry, glucose is obtained from starch.
Anhydrous glucose melts at a temperature of 146 C, it is readily soluble in water. Glucose is about 2 times less sweet than sucrose. When glucose is exposed to strong oxidants, sugar acid is formed. When restored, it turns into hexahedral alcohol -.
Attention!
There are three types of carbohydrates:
- monosaccharides;
- disaccharides;
- polysaccharides.
The main monosaccharides are glucose and fructose, which consist of one molecule, due to which these carbohydrates are quickly broken down, instantly entering the bloodstream. The cells of the brain are “fed” with energy thanks to glucose: for example, the daily rate of glucose required for the brain is 150 g, which is one fourth of the total volume of this carbohydrate received per day from food.
The peculiarity of simple carbohydrates is that, being quickly processed, they are not transformed into fats, while complex carbohydrates (if consumed excessively) can be deposited in the body as fat. Monosaccharides are abundant in many fruits and vegetables, as well as honey.
These carbohydrates, which include sucrose, lactose and maltose, cannot be called complex, since they contain the remains of two monosaccharides. Disaccharides take longer to digest than monosaccharides.
Interesting fact! It has been shown that children and adolescents respond to increased intake of carbohydrates from refined (or refined) foods, the so-called overactive (or hyperactive) behavior. By consistently eliminating foods such as sugar, white flour, pasta and white rice from the diet, behavioral disorders will be significantly reduced.
At the same time, it is important to increase the consumption of fresh vegetables and fruits, legumes, nuts, and cheese. Disaccharides are found in dairy products, pasta and products containing refined sugar. Polysaccharide molecules include tens, hundreds, and sometimes thousands of monosaccharides.
Polysaccharides (namely starch, fiber, cellulose, pectin, inulin, chitin, and glycogen) are most important for the human body for two reasons:
- they take a long time to digest and absorb (in contrast to simple carbohydrates);
- contain many useful substances, including vitamins, minerals and proteins.
Many polysaccharides are present in plant fibers, as a result of which one meal, which is based on raw or boiled vegetables, can almost completely satisfy the body's daily requirement in substances that are sources of energy.
Thanks to polysaccharides, firstly, the necessary sugar level is maintained, and secondly, the brain is provided with the nutrition it needs, which is manifested by increased concentration, improved memory and increased mental activity. Polysaccharides are found in vegetables, fruits, grains, and animal liver.
The benefits of carbohydrates:
- Stimulating the peristalsis of the gastrointestinal tract.
- Absorption and elimination of toxic substances and cholesterol.
- Providing optimal conditions for the functioning of normal intestinal microflora.
- Strengthening the immune system.
- Normalization of metabolism.
- Ensuring the proper functioning of the liver.
- Ensuring a constant flow of sugar into the blood.
- Prevention of the development of tumors in the stomach and intestines.
- Replenishment of vitamins and minerals.
- Providing energy to the brain, as well as the central nervous system.
- Promote the production of endorphins, which are called “hormones of joy”.
- Easing the manifestation of premenstrual syndrome.
Daily carbohydrate requirement
The need for carbohydrates directly depends on the intensity of mental and physical exertion, averaging 300 - 500 g per day, of which at least 20 percent should be easily digestible carbohydrates. Elderly people should include in their daily diet no more than 300 g of carbohydrates, while the amount of easily digestible carbohydrates should vary between 15 and 20 percent.
With obesity and other diseases, it is necessary to limit the amount of carbohydrates, and this should be done gradually, which will allow the body to adapt to the altered metabolism without any problems. It is recommended to start the restriction from 200 - 250 g per day for a week, after which the amount of carbohydrates supplied with food is brought to 100 g per day.
A sharp decrease in carbohydrate intake over a long period of time (as well as a lack of them in the diet) leads to the development of the following disorders:
The listed phenomena disappear after consuming sugar or other sweet foods, but the intake of such foods should be dosed, which will protect the body from gaining extra pounds. An excess of carbohydrates (especially easily digestible ones) in the diet is also harmful to the body, contributing to an increase in sugar, as a result of which part of the carbohydrates is not used, going to the formation of fat, which provokes the development of atherosclerosis, cardiovascular diseases, flatulence, diabetes mellitus, obesity, and caries.
What foods contain carbohydrates?
From the list of carbohydrates below, everyone can make up a completely varied diet (taking into account the fact that this is far from a complete list of foods that contain carbohydrates). Carbohydrates are found in the following foods:
Only a balanced diet will provide the body with energy and health. But for this you need to properly organize your diet. And the first step to a healthy diet is a complex carbohydrate breakfast. So, a portion of whole grain porridge (without dressings, meat and) will provide the body with energy for at least three hours.
In turn, when eating simple carbohydrates (we are talking about sweet pastries, various refined products, sweet coffee and tea), we experience an instant feeling of fullness, but at the same time, a sharp rise in blood sugar occurs in the body, followed by a rapid decline, followed by feeling .
Why is this happening? The fact is that the pancreas is very overloaded, since it has to excrete in order to process refined sugars. The result of this overload is a drop in sugar levels (sometimes below normal) and the appearance of a feeling of hunger.
In order to avoid these disorders, we will consider each carbohydrate separately, determining its benefits and role in providing the body with energy.
An example of the most common naturally occurring disaccharides (oligosaccharide) is sucrose(beet or cane sugar).
Oligosaccharides Are condensation products of two or more molecules of monosaccharides.
Disaccharides - these are carbohydrates, which, when heated with water in the presence of mineral acids or under the influence of enzymes, undergo hydrolysis, splitting into two molecules of monosaccharides.
Physical properties and being in nature
1. It is a colorless crystals of sweet taste, readily soluble in water.
2. The melting point of sucrose is 160 ° C.
3. When the molten sucrose solidifies, an amorphous transparent mass is formed - caramel.
4. Contained in many plants: in the sap of birch, maple, carrots, melons, as well as in sugar beets and sugar cane.
Structure and chemical properties
1. Molecular formula of sucrose - C 12 H 22 O 11
2. Sucrose has a more complex structure than glucose. The sucrose molecule consists of glucose and fructose residues linked to each other through the interaction of hemiacetal hydroxyls (1 → 2) -glycosidic bond:
3. The presence of hydroxyl groups in the sucrose molecule is easily confirmed by the reaction with metal hydroxides.
If a sucrose solution is added to copper (II) hydroxide, a bright blue solution of copper saccharate is formed (a qualitative reaction of polyhydric alcohols).
Video experience "Proof of the presence of hydroxyl groups in sucrose"
4. There is no aldehyde group in sucrose: when heated with an ammonia solution of silver (I) oxide, it does not give a "silver mirror"; when heated with copper (II) hydroxide, it does not form red copper (I) oxide.
5. Sucrose, unlike glucose, is not an aldehyde. Sucrose, while in solution, does not enter into the "silver mirror" reaction, since it is not capable of converting into an open form containing an aldehyde group. Such disaccharides are not capable of oxidizing (i.e., being reducing agents) and are called non-restoring sugars.
Video experience "Lack of the reducing capacity of sucrose"
6. Sucrose is the most important of the disaccharides.
7. It is obtained from sugar beet (it contains up to 28% sucrose by dry matter) or from sugar cane.
Reaction of sucrose with water.
An important chemical property of sucrose is the ability to undergo hydrolysis (when heated in the presence of hydrogen ions). In this case, a glucose molecule and a fructose molecule are formed from one sucrose molecule:
C 12 H 22 O 11 + H 2 O t , H 2 SO 4 → C 6 H 12 O 6 + C 6 H 12 O 6
Video experience "Acid hydrolysis of sucrose"
Among sucrose isomers having the molecular formula C 12 H 22 O 11, maltose and lactose can be isolated.
During hydrolysis, various disaccharides are split into their constituent monosaccharides due to the breaking of bonds between them ( glycosidic bonds):
Thus, the reaction of hydrolysis of disaccharides is the reverse of the process of their formation from monosaccharides.
The use of sucrose
· Food product;
· In the confectionery industry;
Obtaining artificial honey
Disaccharides - these are sugar-like complex carbohydrates, the molecules of which, upon hydrolysis, break down into two molecules of monosaccharides. Molecular formula C 12 H 22 O 11. Disaccharides are found in products of natural origin: sucrose (beet sugar) in large quantities, up to 28%, in sugar beets; lactose (milk sugar) - in milk; trehalose (mushroom sugar) - in mushrooms; maltose (malt sugar) is formed by partial hydrolysis of starch, etc.
By their structure, disaccharides are glycosides. Depending on which hydroxyl of the second monosaccharide is involved in the formation of a bond with the first monosaccharide, there are two types of disaccharides: reducing (reducing); non-restoring.
Reducing disaccharides called glycosyl glycoses; the bond between monosaccharide molecules in these disaccharides is formed due to the hemiacetal hydroxyl of one molecule and the alcoholic hydroxyl (most often at the fourth carbon atom) of the second molecule. The most important representatives: maltose, lactose, cellobiose. In solution, they are in tautomeric forms: cyclic (hemiacetal) and hydroxycarbonyl (aldehyde).
lactose lactose
Structure. The composition of disaccharides can include two identical or different monosaccharides in a semi-acetal (cyclic) form.
Thus, a maltose molecule (malt sugar) consists of two α-D-glucose molecules in pyranose form, linked by an l-4-α-glycosidic bond.
Free hemiacetal hydroxyl is retained in the second monosaccharide residue of the maltose molecule. For this reason, maltose in solution can exist in tautomeric forms: cyclic and hydroxycarbonyl, which are in dynamic equilibrium with each other.
maltose maltose
(hemiacetal form) (hydroxycarbonyl form)
All reducing disaccharides (lactose, cellobiose, etc.) are built on this principle.
Properties of reducing (reducing) disaccharides. Reducing disaccharides are crystalline substances that are readily soluble in water, have a sweet taste, and are hygroscopic. Solutions of these disaccharides are neutral and have optical activity. Chemically, reducing disaccharides exhibit the properties of aldehydes: they give a silver mirror reaction, reduce Fehling's liquid, react with reagents for the carbonyl group (with phenylhydrazine, hydroxylamine). Due to the hemiacetal hydroxyl, disaccharides form glycosides, and also exhibit the properties of polyhydric alcohols: they enter into alkylation and acylation reactions, give a qualitative reaction to polyhydric alcohols (dissolve Cu (OH) 2).
maltose (aldehyde form) maltobionic acid
This group of disaccharides is capable of reducing Ag + to Ag 0 in a silver mirror reaction, Cu 2+ to Cu + in a reaction with Fehling's solution, which is why they are called reducing disaccharides. Like all complex carbohydrates, disaccharides can be hydrolyzed by mineral acids or enzymes.
C 12 H 22 O 11 + H 2 O 
2C 6 N 12 O 6
maltose glucose
Non-reducing disaccharides called glycosyl glycosides; the bond between monosaccharides in these disaccharides is formed with the participation of both hemiacetal hydroxyls, so they cannot pass into other tautomeric forms. Their most important representatives are sucrose and trehalose.
trehalose sucrose
The trehalose molecule consists of two α-D-glucopyranose residues, the sucrose molecule consists of an α-D-glucopyranose residue and a β-D-fructofuranose residue. Since in disaccharides of this group, the bond between monosaccharides is carried out due to both hemiacetal hydroxyls, they cannot tautomerically transform into the oxycarbonyl form, therefore, they cannot react to the carbonyl group, including the aldehyde group (they do not give a silver mirror reaction, do not react with Fehling's solution). Such disaccharides are not capable of exhibiting reducing properties, therefore they are called non-reducing disaccharides. They exhibit the properties of polyhydric alcohols (dissolve copper hydroxide, enter into alkylation and acylation reactions), as all complex carbohydrates are hydrolyzed in the presence of mineral acids or under the action of enzymes.
The structure and properties of sucrose. Sucrose (beet sugar) is one of the most well-known foods for a long time. Sucrose was originally isolated from sugar cane and later from sugar beet. Sucrose is also found in many other plants (corn, maple, palm, etc.).
Molecular composition of sucrose C 12 H 22 O 11.
The sucrose molecule consists of two monosaccharides: glucose in the α-D-pyranose form and fructose in the β-D-furanose form, linked by a 1-2-glycosidic bond with the participation of two hemiacetal (glycosidic) hydroxyls. There are no free hemiacetal hydroxyls in the sucrose molecule; therefore, it cannot tautomerically transform into the hydroxycarbonyl form.
When heated above 160 ° C, sucrose partially decomposes, releasing water and turning into a brown mass - caramel.
An aqueous solution of sucrose dissolves copper hydroxide, forming a solution of copper saccharate, while exhibiting the properties of polyhydric alcohols. When a sucrose solution is heated in the presence of mineral acids, sucrose is hydrolyzed, resulting in a mixture of glucose and fructose in equal amounts (artificial honey). The process of hydrolysis of sucrose is called inversion, since in this case there is a change in the right rotation of the solution to the left one.
Sucrose is widely used as a food product, in the production of confectionery, bakery products, preserves, compotes, jams, etc. In pharmacology, it is used for the preparation of syrups, mixtures, powders, etc.
Esters of sucrose and higher fatty acids have a high detergency and are used as industrial detergents. These products are odorless, completely non-toxic and are completely destroyed by bacteria during biological self-purification of water.
Diesters of higher fatty acids and sucrose are used as emulsifiers in the production of margarine, pharmaceuticals and cosmetics.
Octamethylsucrose is used in the plastics industry as a plasticizer.
Sucrose octaacetate is used as an intermediate layer in the production of triplex glass.
Waste from sugar production (molasses) is used for the production of ethyl alcohol and in the confectionery industry.
Oligosaccharides - carbohydrates, the molecules of which contain from 2 to 10 monosaccharide residues connected by glycosidic bonds. In accordance with this, disaccharides, trisaccharides, etc. are distinguished. Disaccharides - complex sugars, each molecule of which, upon hydrolysis, breaks down into two molecules of monosaccharides. Disaccharides, along with polysaccharides, are one of the main sources of carbohydrates in human and animal food. Structurally, disaccharides are glycosides in which 2 monosaccharide molecules are linked by a glycosidic bond. Among the disaccharides, the most widely known are maltose, lactose and sucrose. Maltose, which is α-glucopyranosyl- (1-> 4) -α-glucopyranose, is formed as an intermediate product under the action of amylases on starch (or glycogen), contains 2 residues of α-D-glucose (the name of a sugar whose hemiacetal hydroxyl is involved in the formation glycosidic bond, ends in nil).
Maltose
In the maltose molecule, the second glucose residue has a free hemiacetal hydroxyl. Such disaccharides have reducing properties. One of the most common disaccharides is sucrose, a common food sugar. The sucrose molecule consists of one D-glucose residue and one D-fructose residue. Therefore, it is α-gluco-pyranosyl- (1-> 2) -β-fructofuranoside:
Sucrose
Unlike most disaccharides, sucrose does not have free hemiacetal hydroxyl and does not have reducing properties. Hydrolysis of sucrose leads to the formation of a mixture called inverted sugar. This mixture is dominated by strongly levogyrate fructose, which inverts (reverses) the sign of rotation of the dextrorotatory solution of the initial sucrose. The disaccharide lactose is found only in milk and consists of D-galactose and D-glucose. This is β-galactopyranosyl- (1-> 4) -glucopyranose:
Due to the presence of free hemiacetal hydroxyl (in the glucose residue) in the molecule, lactose is one of the reducing disaccharides. Among natural trisaccharides, the most famous is raffinose, which contains residues of fructose, glucose and galactose. Raffinose is found in large quantities in sugar beets and many other plants. In general, the oligosaccharides present in plant tissues are more diverse in their composition than the oligosaccharides of animal tissues.
30 Question. Heteropolysaccharides
Chondroitin sulfates - components of heart valves, nasal septum, cartilage tissue. M. b. several types. Handroitin - 4-sulfate and 6-sulfate. Heteropolysaccharide consists of repeating units of disaccharides β (D) -glucuranosyl-1,3-β (D, N) -acetylgalactosamine. Sulfate at positions 4 and 6.
Glaluronic Xylot - is contained in the connective, integumentary tissues, is part of the vitreous body of the eye. Viscous substance, well protects the eye bones from external influences. When hydrolyzed, forms glucuronic acid and N-acetylglucosamine. The bond is 1,3-β-glycosidic.
Heparin –Contained in the liver, in the spleen, a strong anticoagulant, protects the blood from clotting (1 mg of heparin protects against clotting 500ml) is present on the surface of many cells and inside cells.
In medical practice, it is used for the treatment of thrombosis, burns, during blood transfusion as a stabilizer.
The composition includes repeating units from the residues of 6 sugars N-acetylglucosamine, its sulfo-derivative, non-acetylated derivative.
Homopolysaccharides(starch, cellulose, pectin and others)
Hydrolysis gives glucose
Starch is digested by the action of amylase (1,4-glycosidase), which cleaves α-1,4-glycosidic bonds.
Starch consists of amylose (lin. structure and amylopectin) branched structure, but every 25 fragments.
All starches differ in the amount of amylose amylopectin.
Acid hydrolysis breaks down starch into dextrins (red color). Coloring with iodine indicates cleavage. If the color is pale, then the cleavage is greater.
Glycogen resembles amylopectin (cleavage for every 10-12 bonds) in the liver, in the muscles there is a spare nutrition.
Cellulose has a 1,4-β-glycosidic bond.
Pectin to-you - polysaccharides of fruits, fruits, vegetables, are methyl esters of galacturonic acid, the bond is 1,4-α-glycosidic.
Glycosides - derivatives of hydrocarbons by glycosidic hydrolysis.
Amygdalin - part of almonds. Glucose linked by 1,6-β-glycosidic bonds.
Glycovanillin (glucose, β glycosidic bond).
Sinigrin (part of mustard).
Neuraminic acid - condensation product of pyruvic acid and N-acetylmonosamine. It is a part of gangmosides (in lipids).
Muranic acid (part of the walls of bacteria).
Tanning islands - of plant origin. Soluble in water, give colored solutions with ferric chloride. They are divided into 2 types: hydrolysable and non-hydrolysable (condense when T with kilota).
Itype - fineness - derivatives of glucose and di-, gallic acid trimmers.
(gallic acid 
, capable of forming dioxides)
The tones can be different:
Tonin Fischer's structure is:
DH - digalic acid
G - gallic acid
The exact structure of natural tannins has not been established.
Used: in medicine, pharmacy, for the isolation of alkaloid reagents.
Mr m. up to 3000, are contained in the bark of trees, in the fruits of some plants.
Exist ellag oak islands , characterized in that during hydrolysis they form insoluble ellagic to - that.
Type II - kapihin(condensed tanning substances).
F 
ravonoids: compounds: leukoanthocyanin, catechin, flavonone, flavonol, flavone, anticyanogen.
Catechin contain in A and B OH-, CH2- and differ in them. They do not form glycosides in nature. Easily oxidized and capable of polymerization, crystalline colorless substances. Contained in the fruits of apple, cherry, pear, in the leaves of the shoots of the tea tree.
The enzymatic process leads to dimerization. Studies winemaking, tea industry, cocoa production.
Compounds - flavonoids have a vitamin capacity (P). Increase the elasticity of blood capillaries, most of all inherent in catechin.
IN 
itamine P - quracetyl glycoside
Quarcetyl- aglycone 6β (α) -ramnosido- (D) -glucose-rhamnose. Bonding due to 6 carbon atoms in glucose. In the absence of routine in food, the capillaries become permeable -> purple disease.
Anthocyanins- coloring plant islands (dilfinidin, piporgonidin, cyanidin (rose and cornflower)). They differ in radicals. They exist in the form of glucosides.
Carbohydrates- organic substances, the molecules of which consist of carbon atoms, hydrogen and oxygen, and hydrogen and oxygen are in them, as a rule, in the same ratio as in a water molecule (2: 1).
General carbohydrate formula - С n (Н 2 О) m, that is, they seem to be composed of carbon and water, hence the name of the class, which has historical roots. It emerged from the analysis of the first known carbohydrates. Later it was found that there are carbohydrates in the molecules of which the specified ratio (2: 1) is not observed, for example, deoxyribose - C 5 H 10 O 4. There are also known organic compounds, the composition of which corresponds to the above general formula, but which do not belong to the class of carbohydrates. These include, for example, formaldehyde CH 2 O and acetic acid CH 3 COOH.
However, the name "carbohydrates" has taken root and is now generally accepted for these substances.
According to their ability to hydrolyze, carbohydrates can be divided into three main groups: mono-, di- and polysaccharides.
Monosaccharides- carbohydrates that do not hydrolyze (do not decompose by water). In turn, depending on the number of carbon atoms, monosaccharides are subdivided into trioses (molecules of which contain three carbon atoms), tetroses (four carbon atoms), pentoses (five), hexoses (six), etc.
In nature, monosaccharides are mainly represented pentoses and hexoses.
TO pentose include, for example, ribose - C 5 H 10 O 5 and deoxyribose (ribose, from which the oxygen atom was "taken away") - C 5 H 10 O 4. They are part of RNA and DNA and define the first part of the names of nucleic acids.
TO hexose having the general molecular formula C 6 H 12 O 6 include, for example, glucose, fructose, galactose.
Disaccharides- carbohydrates, which are hydrolyzed to form two molecules of monosaccharides, for example hexoses. The general formula of the overwhelming majority of disaccharides is easy to deduce: you need to "add" two formulas of hexoses and "subtract" from the resulting formula the water molecule - C 12 H 22 O 11. Accordingly, the general hydrolysis equation can also be written:
Disaccharides include:
1. Sucrose(common food sugar), which, when hydrolyzed, forms one glucose molecule and a fructose molecule. It is found in large quantities in sugar beets, sugar cane (hence the name - beet or cane sugar), maple (Canadian pioneers mined maple sugar), sugar palm, corn, etc.
2. Maltose(malted sugar), which is hydrolyzed to form two glucose molecules. Maltose can be obtained by hydrolysis of starch by the action of enzymes contained in malt - germinated, dried and ground barley grains.
3. Lactose(milk sugar), which is hydrolyzed to form glucose and galactose molecules. It is found in mammalian milk (up to 4-6%), has a low sweetness and is used as a filler in pills and pharmaceutical tablets.
The sweet taste of different mono- and disaccharides is different. So, the sweetest monosaccharide - fructose - is 1.5 times sweeter than glucose, which is taken as the standard. Sucrose (disaccharide), in turn, is 2 times sweeter than glucose and 4-5 times sweeter than lactose, which is almost tasteless.
Polysaccharides- starch, glycogen, dextrins, cellulose, etc. - carbohydrates, which are hydrolyzed to form many molecules of monosaccharides, most often glucose.
To derive the formula of polysaccharides, you need to "take away" the water molecule from the glucose molecule and write the expression with the index n: (С 6 Н 10 О 5) n, because it is due to the splitting of water molecules that di- and polysaccharides are formed in nature.
The role of carbohydrates in nature and their importance for human life are extremely great. Being formed in plant cells as a result of photosynthesis, they act as a source of energy for animal cells. This primarily applies to glucose.
Many carbohydrates (starch, glycogen, sucrose) perform a storage function, the role of the reserve of nutrients.
RNA and DNA acids, which include some carbohydrates (pentose-ribose and deoxyribose), perform the functions of transmitting hereditary information.
Cellulose- the building material of plant cells - plays the role of a framework for the membranes of these cells. Another polysaccharide, chitin, plays a similar role in the cells of some animals: it forms the outer skeleton of arthropods (crustaceans), insects, and arachnids.
Carbohydrates ultimately serve as a source of our nutrition: we consume grain containing starch, or feed it to animals, in which the body turns starch into proteins and fats. The most hygienic clothing is made of cellulose or cellulose-based products: cotton and linen, rayon fiber, acetate silk. Timber houses and furniture are built from the same cellulose that makes wood.
At the heart of the production of photographic and film films is the same cellulose. Books, newspapers, letters, banknotes - all these are products of the pulp and paper industry. This means that carbohydrates provide us with everything we need for life: food, clothing, shelter.
In addition, carbohydrates are involved in the construction of complex proteins, enzymes, and hormones. Carbohydrates are also such vital substances as heparin (it plays an important role - it prevents blood clotting), agar-agar (it is obtained from seaweed and used in the microbiological and confectionery industries - remember the famous bird's milk cake).
It should be emphasized that the only type of energy on Earth (besides nuclear, of course) is the energy of the Sun, and the only way to accumulate it to ensure the vital activity of all living organisms is the process photosynthesis flowing in the cells of living plants and leading to the synthesis of carbohydrates from water and carbon dioxide. It is during this transformation that oxygen is formed, without which life on our planet would be impossible:
Monosaccharides. Glucose
Glucose and fructose- solid colorless crystalline substances. Glucose is found in grape juice (hence the name "grape sugar"), together with fructose, which is found in some fruits and fruits (hence the name "fruit sugar"), makes up a significant part of honey. The blood of humans and animals constantly contains about 0.1% glucose (80-120 mg in 100 ml of blood). Most of it (about 70%) undergoes slow oxidation in tissues with the release of energy and the formation of final products - carbon dioxide and water (glycolysis process):
The energy released during glycolysis largely meets the energy requirements of living organisms.
An excess of 180 mg blood glucose in 100 ml of blood indicates a violation of carbohydrate metabolism and the development of a dangerous disease - diabetes mellitus.
The structure of the glucose molecule
The structure of the glucose molecule can be judged on the basis of experimental data. It reacts with carboxylic acids to form esters containing 1 to 5 acid residues. If a glucose solution is added to freshly obtained copper (II) hydroxide, the precipitate dissolves and a bright blue solution of a copper compound is formed, i.e., a qualitative reaction to polyhydric alcohols occurs. Therefore, glucose is a polyhydric alcohol. If the resulting solution is heated, then a precipitate will again fall out, but already reddish in color, that is, a qualitative reaction to aldehydes will occur. Similarly, if a glucose solution is heated with an ammoniacal solution of silver oxide, a "silver mirror" reaction will occur. Consequently, glucose is both a polyhydric alcohol and an aldehyde - aldehyde alcohol. Let's try to derive the structural formula of glucose. There are six carbon atoms in the C 6 H 12 O 6 molecule. One atom is part of aldehyde group:
The other five atoms bond to five hydroxy groups.
And finally, we distribute the hydrogen atoms in the molecule taking into account the fact that carbon is tetravalent:
However, it was found that in a glucose solution, in addition to linear (aldehyde) molecules, there are also cyclic molecules that make up crystalline glucose. The transformation of linear molecules into cyclic ones can be explained if we remember that carbon atoms can freely rotate around σ-bonds located at an angle of 109 ° 28 ′. In this case, the aldehyde group (1st carbon atom) can approach the hydroxyl group of the fifth carbon atom. In the first, under the influence of the hydroxy group, the π-bond is broken: a hydrogen atom is attached to the oxygen atom, and the oxygen of the hydroxy group that has "lost" this atom closes the cycle:
As a result of this rearrangement of atoms, a cyclic molecule is formed. The cyclic formula shows not only the bond order of atoms, but also their spatial arrangement. As a result of the interaction of the first and fifth carbon atoms, a new hydroxy group appears at the first atom, which can occupy two positions in space: above and below the plane of the cycle, and therefore two cyclic forms of glucose are possible:
but) α-form of glucose- hydroxyl groups at the first and second carbon atoms are located on one side of the ring of the molecule;
b) β-form glucose- hydroxyl groups are located on opposite sides of the ring of the molecule:
In an aqueous solution of glucose, three of its isomeric forms are in dynamic equilibrium - the cyclic α-form, the linear (aldehyde) form, and the cyclic β-form:
In the established dynamic equilibrium, the β-form prevails (about 63%), since it is energetically more preferable - it has OH groups at the first and second carbon atoms on opposite sides of the cycle. In the α-form (about 37%), the OH-groups of the same carbon atoms are located on one side of the plane, so it is energetically less stable than the β-form. The proportion of the linear form in equilibrium is very small (only about 0.0026%).
Dynamic equilibrium can be shifted. For example, when an ammonia solution of silver oxide acts on glucose, the amount of its linear (aldehyde) form, which is very small in solution, is replenished all the time due to cyclic forms, and glucose is completely oxidized to gluconic acid.
The isomer of glucose aldehyde alcohol is ketone alcohol - fructose:
Chemical properties of glucose
The chemical properties of glucose, like any other organic substance, are determined by its structure. Glucose has a dual function, being and aldehyde, and polyhydric alcohol, therefore, it is characterized by the properties of both polyhydric alcohols and aldehydes.
Reactions of glucose as a polyhydric alcohol.
Glucose gives a qualitative reaction of polyhydric alcohols (remember glycerin) with freshly obtained copper (II) hydroxide, forming a bright blue solution of a copper (II) compound.
Glucose, like alcohols, can form esters.
Reactions of glucose as aldehyde
1. Oxidation of the aldehyde group... Glucose as an aldehyde is capable of being oxidized to the corresponding (gluconic) acid and give qualitative reactions of aldehydes.
Silver Mirror Reaction:
Reaction with freshly prepared Cu (OH) 2 when heated:
Recovery of the aldehyde group... Glucose can be reduced to the corresponding alcohol (sorbitol):
Fermentation reactions
These reactions proceed under the action of special biological catalysts of a protein nature - enzymes.
1. Alcoholic fermentation:
it has long been used by humans for the production of ethyl alcohol and alcoholic beverages.
2. Lactic acid fermentation:
which forms the basis of the life of lactic acid bacteria and occurs when milk is sour, sauerkraut and cucumbers, silage of green fodder. \
Chemical properties of glucose - compendium
Polysaccharides. Starch and cellulose.
Starch- white amorphous powder, does not dissolve in cold water. In hot water, it swells and forms a colloidal solution - starch paste.
Starch is contained in the cytoplasm of plant cells in the form of grains of a reserve nutrient. Potato tubers contain about 20% starch, wheat and corn grains - about 70%, and rice - almost 80%.
Cellulose(from Lat. cellula - cell), isolated from natural materials (for example, cotton wool or filter paper), is a solid fibrous substance, insoluble in water.
Both polysaccharides are of plant origin, but they play different roles in the plant cell: cellulose is a building, structural function, and starch is a storage function. Therefore, cellulose is an indispensable element of the cell wall of plants. Cotton fibers contain up to 95% cellulose, flax and hemp fibers - up to 80%, and wood contains about 50%.
The structure of starch and cellulose
The composition of these polysaccharides can be expressed by the general formula (C 6 H 10 O 5) n... The number of repeating units in a starch macromolecule can range from several hundred to several thousand. Cellulose, on the other hand, has a significantly larger number of units and, consequently, a molecular weight that reaches several million.
Carbohydrates differ not only in molecular weight, but also in structure. Starch is characterized by two types of macromolecule structures: linear and branched. The smaller macromolecules of that part of the starch, which is called amylose, have a linear structure, and the molecules of the other constituent part of starch, amylopectin, have a branched structure.
In starch, amylose accounts for 10-20%, and amylopectin accounts for 80-90%. Starch amylose dissolves in hot water, while amylopectin only swells.
The structural units of starch and cellulose are built in different ways. If the starch link includes residues α-glucose, then cellulose - residues β-glucose oriented to natural fibers:
Chemical properties of polysaccharides
1. Formation of glucose. Starch and cellulose undergo hydrolysis to form glucose in the presence of mineral acids, such as sulfuric acid:
In the digestive tract of animals, starch undergoes a complex stepwise hydrolysis:
The human body is not adapted to digest cellulose, since it does not have the enzymes necessary to break the bonds between β-glucose residues in the cellulose macromolecule.
Only termites and ruminants (for example, cows) have microorganisms in the digestive system that produce the necessary enzymes.
2. Formation of esters... Starch can form esters due to hydroxy groups, but these esters have not found practical use.
Each cellulose unit contains three free alcoholic hydroxy groups. Therefore, the general formula for cellulose can be written as follows:
Due to these alcoholic hydroxy groups, cellulose can form esters, which are widely used.
When processing cellulose with a mixture of nitric and sulfuric acids, depending on the conditions, mono-, di- and trinitrocellulose is obtained:
Use of carbohydrates
A mixture of mono- and dinitrocellulose is called colloxylin... A solution of colloxylin in a mixture of alcohol and diethyl ether - collodion - is used in medicine for sealing small wounds and for gluing dressings to the skin.
When a solution of colloxylin and camphor dries in alcohol, celluloid- one of the plastics, which for the first time began to be widely used in everyday life of a person (it is used to make photographic and film films, as well as various consumer goods). Colloxylin solutions in organic solvents are used as nitro lacquers. And when dyes are added to them, durable and aesthetic nitro paints are obtained, which are widely used in everyday life and technology.
Like other organic substances containing nitro groups in the molecules, all types of nitrocellulose are flammable. Especially dangerous in this respect trinitrocellulose- the strongest explosive. Under the name "pyroxylin" it is widely used for the production of weapons projectiles and blasting operations, as well as for the production of smokeless powder.
With acetic acid (in industry for this purpose, a more powerful esterifying agent, acetic anhydride, is used), analogous (di- and tri-) esters of cellulose and acetic acid are obtained, which are called cellulose acetate:
Cellulose acetate used to obtain varnishes and paints, it also serves as a raw material for the manufacture of artificial silk. To do this, it is dissolved in acetone, and then this solution is pushed through the thin holes of the spinnerets (metal caps with numerous holes). The escaping streams of solution are blown over with warm air. At the same time, acetone evaporates quickly, and the drying cellulose acetate forms thin shiny threads that are used to make yarn.
Starch, unlike cellulose, gives a blue coloration when interacting with iodine. This reaction is qualitative for starch or iodine, depending on which substance is required to be proven.
Reference material for passing the test:
Mendeleev table
Solubility table