Disaccharides composition. Chemical properties of disaccharides and polysaccharides

Disaccharides: sucrose, lactose, maltose, etc. are widespread and important as components of food products.

By chemical structure disaccharides are monosaccharide glycosides. Most disaccharides are composed of hexoses, but in nature disaccharides are known, consisting of one hexose molecule and one pentose molecule.

When a disaccharide is formed, one monosaccharide molecule always forms a bond with a second molecule using its hemiacetal hydroxyl. Another monosaccharide molecule can be combined either with a hemiacetal hydroxyl or with one of the alcoholic hydroxyls. In the latter case, one hemiacetal hydroxyl will remain free in the disaccharide molecule.

Maltose- reserve oligosaccharide - found in many plants in not large quantities, accumulates in large quantities in malt - usually in barley seeds germinated under certain conditions. This is why maltose is often referred to as malt sugar. Maltose is formed in plant and animal organisms as a result of starch hydrolysis by amylases.

Maltose contains two D-glucopyranose residues linked by a (1®4) glycosidic bond.

Maltose has regenerating properties, which is used for its quantifying... It is readily soluble in water. The solution shows mutarotation.

Under the action of the enzyme α-glucosidase (maltase), malt sugar is hydrolyzed to form two glucose molecules:

Maltose is fermented by yeast. This ability of maltose is used in fermentation technology for the production of beer, ethyl alcohol, etc. from starch-containing raw materials.

Lactose- reserve disaccharide (milk sugar) - is contained in milk (4-5%) and is obtained in the cheese-making industry from milk whey after the cottage cheese is separated. Fermented only with special lactose yeast contained in kefir and koumiss. Lactose is built from the residues of b-D-galactopyranose and a-D-glucopyranose, interconnected by a b- (1 → 4) -glycosidic bond. Lactose is a reducing disaccharide, where the free hemiacetal hydroxyl belongs to the glucose residue, and the oxygen bridge connects the first carbon atom of the galactose residue to the fourth carbon atom of the glucose residue.

Lactose is hydrolyzed by the enzyme b-galactosidase (lactase):

Lactose differs from other sugars in the absence of hygroscopicity - it does not damp. Milk sugar is used as a pharmaceutical and as a nutritional supplement for infants. Aqueous solutions of lactose mutarose, lactose has 4-5 times less sweet taste than sucrose.

Sucrose(cane sugar, beet sugar) is a reserve disaccharide - it is extremely widespread in plants, especially in beet roots (from 14 to 20%), as well as in sugar cane stalks (from 14 to 25%). Sucrose is a transport sugar in the form of which carbon and energy are transported throughout the plant. It is in the form of sucrose that carbohydrates move from the places of synthesis (leaves) to the place where they are deposited in the reserve (fruits, roots, seeds).

Sucrose consists of a-D-glucopyranose and b-D-fructofuranose linked by an a-1 → b-2-bond due to glycosidic hydroxyls:

Sucrose does not contain free hemiacetal hydroxyl; therefore, it is not capable of oxy-oxo-tautomerism and is a non-reducing disaccharide.

When heated with acids or under the action of the enzymes a-glucosidase and b-fructofuranosidase (invertase), sucrose is hydrolyzed to form a mixture of equal amounts of glucose and fructose, which is called invert sugar.

The most important disaccharides- sucrose, maltose and lactose. They all have the general formula C12H22O11, but their structure is different.

Sucrose consists of 2 cycles linked by glycoside hydroxide:

Maltose consists of 2 glucose residues:

Lactose:

All disaccharides are colorless crystals, sweet in taste, readily soluble in water.

Chemical properties of disaccharides.

1) Hydrolysis. As a result, the connection between 2 cycles is broken and monosaccharides are formed:

Reducing dicharides - maltose and lactose. They react with an ammoniacal silver oxide solution:

They can reduce copper (II) hydroxide to copper (I) oxide:

The reducing ability is explained by the cyclic form and the content of glycosidic hydroxyl.

There is no glycosidic hydroxyl in sucrose, therefore, the cyclic form cannot be opened and transferred to the aldehyde form.

The use of disaccharides.

The most common disaccharide is sucrose.

Disaccharides (maltose, lactose, sucrose)

It is a source of carbohydrates in human food.

Lactose is found in milk and is obtained from it.

Maltose is found in germinated cereal seeds and is formed by the enzymatic hydrolysis of starch.

Additional materials on the topic: Disaccharides. Disaccharide properties.

Reducing disaccharides

Reducing disaccharides include maltose or malt sugar. Maltose is obtained by partial hydrolysis of starch in the presence of enzymes or an aqueous acid solution. Maltose is built from two glucose molecules (i.e. it is a glucoside). Glucose is present in maltose in the form of a cyclic hemiacetal. Moreover, the bond between the two cycles is formed by the glycosidic hydroxyl of one molecule and the hydroxyl of the fourth tetrahedron of the other. The structural peculiarity of the maltose molecule is that it is built from glucose α-anomers:

The presence of free glycosidic hydroxyl determines the main properties of maltose:

Disaccharides

Ability for tautomerism and mutarotation:

Maltose can be oxidized and reduced:

For the reducing disaccharide, phenylhydrazone and ozazone can be obtained:

The reducing disaccharide can be alkylated with methyl alcohol in the presence of hydrogen chloride:

Regardless of whether reducing or not reducing - the disaccharide can be alkylated with methyl iodide in the presence of wet silver oxide or acetylated with acetic anhydride. In this case, all hydroxyl groups of the disaccharide enter into the reaction:

Another product of the hydrolysis of the higher polysaccharide is cellobiose disaccharide:

Cellobiose, like maltose, is built from two glucose residues. The fundamental difference is that the residues in the cellobiose molecule are linked by β-glycosidic hydroxyl.

Judging by the structure of the cellobiose molecule, it should be a reducing sugar. It also has all the chemical properties of disaccharides.

Another reducing sugar is lactose - milk sugar. This disaccharide is found in every milk and gives the milk flavor, although it is less sweet than sugar. Built from β-D-galactose and α-D-glucose residues. Galactose is an epimer of glucose and differs in the configuration of the fourth tetrahedron:

Lactose has all the properties of reducing sugars: tautomerism, mutarotation, oxidation to lactobionic acid, reduction, formation of hydrazones and ozazones.

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Question 2. Disaccharides

Formation of glycosides

The glycosidic bond is important biological significance, because it is with the help of this bond that the covalent binding of monosaccharides in the composition of oligo- and polysaccharides is carried out. When a glycosidic bond is formed, the anomeric OH group of one monosaccharide interacts with the OH group of another monosaccharide or alcohol. In this case, the splitting off of the water molecule occurs and the formation O-glycosidic linkage... All linear oligomers (except disaccharides) or polymers contain monomeric residues involved in the formation of two glycosidic bonds, except for terminal residues. Some glycosidic residues can form three glycosidic bonds, which is characteristic of branched oligo- and polysaccharides. Oligo- and polysaccharides can have a terminal monosaccharide residue with a free anomeric OH-group not used in the formation of a glycosidic bond. In this case, when the cycle is opened, the formation of a free carbonyl group that can be oxidized is possible. Such oligo- and polysaccharides have reducing properties and are therefore called reducing or reducing.

Figure - The structure of the polysaccharide.

A. Formation of a-1,4- and a-1,6-glycosidic bonds.

B. Structure of linear polysaccharide:

1 - a-1,4-glycosidic bonds between manomers;

2 - non-reducing end (the formation of a free carbonyl group in an anomeric carbohydrate is not possible);

3 - reducing end (it is possible to open the cycle with the formation of a free carbonyl group at the anomeric carbon).

The anomeric OH-group of a monosaccharide can interact with the NH2-group of other compounds, which leads to the formation of an N-glycosidic bond. A similar bond is present in nucleotides and glycoproteins.

Figure - The structure of the N-glycosidic bond

Question 2. Disaccharides

Oligosaccharides contain from two to ten monosaccharide residues linked by a glycosidic bond. Disaccharides are the most common oligomeric carbohydrates found in free form, i.e. not related to other connections. By their chemical nature, disaccharides are glycosides that contain 2 monosaccharides linked by a glycosidic bond in the a- or b-configuration. Food contains mainly disaccharides such as sucrose, lactose and maltose.

Drawing - Disaccharides of food

Sucrose - a disaccharide consisting of a-D-glucose and b-D-fructose linked by an a, b-1,2-glycosidic bond. In sucrose, both anomeric OH groups of glucose and fructose residues are involved in the formation of a glycosidic bond. Hence sucrose does not apply to reducing sugars... Sucrose is a sweet-tasting soluble disaccharide.

Disaccharides. Disaccharide properties.

Plants are a source of sucrose, especially sugar beets and sugar cane. The latter explains the emergence of the trivial name for sucrose - "cane sugar".

Lactose- milk sugar. Lactose is hydrolyzed to form glucose and galactose. The most important disaccharide of mammalian milk. V cow's milk contains up to 5% lactose, in women - up to 8%. In lactose, the anomeric OH group of the first carbon atom of the D-galactose residue is linked by a b-glycosidic bond to the fourth carbon atom of D-glucose (b-1,4-bond). Since the anomeric carbon atom of the glucose residue is not involved in the formation of a glycosidic bond, therefore, lactose refers to reducing sugars.

Maltose comes with products containing partially hydrolyzed starch, such as malt, beer. Maltose is formed by the breakdown of starch in the intestine and partly in oral cavity... Maltose consists of two D-glucose residues linked by an a-1,4-glycosidic bond... Refers to reducing sugars.

Question 3. Polysaccharides:

Classification

Depending on the structure of monosaccharide residues, polysaccharides can be divided into homopolysaccharides(all monomers are identical) and heteropolysaccharides(monomers are different). Both types of polysaccharides can have both linear and branched monomers.

There are the following structural differences between polysaccharides:

the structure of the monosaccharides that make up the chain;
the type of glycosidic bonds connecting the monomers in the chain;
the sequence of monosaccharide residues in the chain.

Depending on the functions they perform ( biological role) polysaccharides can be divided into 3 main groups:

reserve polysaccharides that perform an energy function. These polysaccharides serve as a source of glucose for the body to use as needed. The reserve function of carbohydrates is provided by their polymeric nature. Polysaccharides more difficult to dissolve than monosaccharides, therefore, they do not affect osmotic pressure and therefore can accumulate in the cell, for example, starch - in plant cells, glycogen - in animal cells;
structural polysaccharides that provide cells and organs with mechanical strength;
polysaccharides that make up the extracellular matrix, take part in the formation of tissues, as well as in the proliferation and differentiation of cells. Intercellular matrix polysaccharides are water-soluble and highly hydrated.

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Structural formula

Molecular mass: 342.297

Maltose(from the English malt - malt) - malt sugar, 4-O-α-D-glucopyranosyl-D-glucose, a natural disaccharide consisting of two glucose residues; is found in large quantities in sprouted grains (malt) of barley, rye and other cereals; found also in tomatoes, pollen and nectar of a number of plants.
The biosynthesis of maltose from β-D-glucopyranosyl phosphate and D-glucose is known only in some bacterial species. In animal and plant organisms, maltose is formed during the enzymatic breakdown of starch and glycogen (see Amylase).
Maltose is easily absorbed by the human body. The splitting of maltose to two glucose residues occurs as a result of the action of the enzyme a-glucosidase, or maltase, which is contained in the digestive juices of animals and humans, in sprouted grain, in molds and yeast. The genetically determined absence of this enzyme in the mucous membrane of the human intestine leads to congenital maltose intolerance - a serious illness that requires the elimination of maltose, starch and glycogen from the diet or the addition of the maltase enzyme to food.

Chemical name

α-Maltose - (2R, 3R, 4S, 5R, 6R) -5 - [(2R, 3R, 4S, 5R, 6R) -2,3,4-trihydroxy-6- (hydroxymethyl) oxanyl] oxy-6- (hydroxymethyl) oxane-2,3,4-triol
β-Maltose - (2S, 3R, 4S, 5R, 6R) -5 - [(2R, 3R, 4S, 5R, 6R) -2,3,4-trihydroxy-6- (hydroxymethyl) oxanyl] oxy-6- (hydroxymethyl) oxane-2,3,4-triol

Physical properties

Maltose is a reducing sugar as it has an unsubstituted hemiacetal hydroxyl group.
When maltose is boiled with dilute acid and under the action of the enzyme, maltose is hydrolyzed (two molecules of glucose C6H12O6 are formed).
C12H22O11 + H2O → 2C6H12O6

(from the English malt - malt), malt sugar, a natural disaccharide consisting of two glucose residues; is found in large quantities in sprouted grains (malt) of barley, rye and other cereals; found also in tomatoes, pollen and nectar of a number of plants. M. is easily soluble in water and has a sweet taste; is a reducing sugar as it has an unsubstituted hemiacetal hydroxyl group. The biosynthesis of M. from b-D-glucopyranosyl phosphate and D-glucose is known only in some species of bacteria. In animal and plant organisms, M.

formed by enzymatic breakdown of starch and glycogen (see Amylase). The splitting of M. to two glucose residues occurs as a result of the action of the enzyme a-glucosidase, or maltase, which is contained in the digestive juices of animals and humans, in sprouted grain, in molds and yeast. The genetically determined absence of this enzyme in the mucous membrane of the human intestine leads to congenital intolerance to M., a serious illness requiring the exclusion of M., starch and glycogen from the diet, or the addition of the enzyme maltase to food.

Lit .: Chemistry of carbohydrates, M., 1967; Harris G., Fundamentals of human biochemical genetics, translated from English, M., 1973.

One of the varieties organic compounds necessary for the full functioning of the human body are carbohydrates.

They are divided into several types according to their structure - monosaccharides, disaccharides and polysaccharides. You need to figure out what they are for and what are their chemical and physical properties.

Carbohydrates are compounds that contain carbon, hydrogen and oxygen. Most often they have natural origin, although some are produced industrially. Their role in the life of living organisms is enormous.

Their main functions are called the following:

Energy... These compounds are the main source of energy. Most of organs can work fully due to the energy obtained during the oxidation of glucose.
Structural... Carbohydrates are essential for the formation of almost all cells in the body. Fiber plays the role of a supporting material, and in bones and cartilage tissue there are complex carbohydrates. One of the components of cell membranes is hyaluronic acid. Also, carbohydrate compounds are required in the process of enzyme production.
Protective... During the functioning of the body, the work of the glands that secrete secretory fluids is carried out, which are necessary to protect the internal organs from pathogenic effects. A significant portion of these fluids are carbohydrates.
Regulatory... This function is manifested in the influence on human body glucose (maintains homeostasis, controls osmotic pressure) and fiber (affects gastrointestinal peristalsis).
Special functions... They are characteristic of certain types of carbohydrates. To such special functions include: participation in the transmission of nerve impulses, the formation of different blood groups, etc.

Based on the fact that the functions of carbohydrates are quite diverse, it can be assumed that these compounds should differ in their structure and characteristics.

This is indeed the case, and their main classification includes such varieties as:

... They are considered to be the simplest. Other types of carbohydrates enter the hydrolysis process and break down into smaller components. Monosaccharides do not have this ability, they are the final product.
Disaccharides... In some classifications, they are referred to as oligosaccharides. They contain two monosaccharide molecules. It is on them that the disaccharide is divided during hydrolysis.
Oligosaccharides... This compound contains from 2 to 10 molecules of monosaccharides.
Polysaccharides... These compounds are the largest variety. They contain more than 10 molecules of monosaccharides.

Each type of carbohydrate has its own characteristics. We need to consider them in order to understand how each of them affects the human body and what its benefits are.

These compounds are the simplest form of carbohydrates. They contain one molecule, therefore, during hydrolysis, they do not divide into small blocks. When monosaccharides are combined, disaccharides, oligosaccharides and polysaccharides are formed.

They are distinguished by their solid state of aggregation and sweet taste. They have the ability to dissolve in water. They can also dissolve in alcohols (the reaction is weaker than with water). Monosaccharides hardly react when mixed with esters.

Natural monosaccharides are most often mentioned. Some of them are consumed by people along with food. These include glucose, fructose and galactose.

chocolate;
fruits;
some types of wine;
syrups, etc.

The main function of this type of carbohydrates is energy. This is not to say that the body cannot do without them, but they have properties that are important for the full functioning of the body, for example, participation in metabolic processes.

The body absorbs monosaccharides faster than anything that happens in the digestive tract. The process of assimilation of complex carbohydrates, in contrast to simple connections is not that simple. First, complex compounds must be divided into monosaccharides, only after that they are absorbed.

This is one of the most common types of monosaccharides. It is a white crystalline substance that forms naturally - during photosynthesis or hydrolysis. The compound formula is C6H12O6. The substance is highly soluble in water and has a sweet taste.

Glucose provides energy to muscle and brain cells. When it enters the body, the substance is absorbed, enters the bloodstream and spreads throughout the body. There it is oxidized with the release of energy. It is the main source of energy for the brain.

With a lack of glucose in the body, hypoglycemia develops, which primarily affects the functioning of the brain structures. However, its excessive content in the blood is also dangerous, since it leads to the development diabetes mellitus... Also when consumed a large number glucose begins to increase body weight.

Fructose

It is one of the monosaccharides and is very similar to glucose. Differs in slower rates of assimilation. This is because absorption requires fructose to be converted to glucose first.

Therefore, this compound is considered harmless for diabetics, since its consumption does not lead to a sharp change in the amount of sugar in the blood. Nevertheless, with such a diagnosis, caution is still necessary.

Fructose has the ability to rapidly convert to fatty acids, which leads to the development of obesity. Also because of this compound, insulin sensitivity decreases, which causes type 2 diabetes.

This substance can be obtained from berries and fruits, and also from honey. Usually it is there in combination with glucose. The connection is also inherent White color... The taste is sweet, and this feature is more intense than in the case of glucose.

Other connections

There are other monosaccharide compounds as well. They can be natural or semi-artificial.

Galactose is natural. She is also contained in food products but is not found in its pure form. Galactose is the result of the hydrolysis of lactose. Milk is called its main source.

Other naturally occurring monosaccharides are ribose, deoxyribose and mannose.

There are also varieties of such carbohydrates, for which industrial technologies are used.

These substances are also found in food and enter the human body:

rhamnose;
erythrulose;
ribulose;
D-xylose;
L-allose;
D-sorbose, etc.

Each of these compounds has its own characteristics and functions.

Disaccharides and their uses

The next type of carbohydrate compounds are disaccharides. They are considered complex substances. As a result of hydrolysis, two molecules of monosaccharides are formed from them.

This type of carbohydrate has the following characteristics:

hardness;
solubility in water;
poor solubility in concentrated alcohols;
sweet taste;
color - from white to brown.

The main chemical properties of disaccharides are hydrolysis reactions (breakdown of glycosidic bonds and the formation of monosaccharides) and condensation (polysaccharides are formed).

There are 2 types of such connections:

Restorative... Their feature is the presence of a free hemiacetal hydroxyl group. Due to it, such substances have reducing properties. This group of carbohydrates includes cellobiose, maltose and lactose.
Non-restoring... These compounds are not reducible because they lack a hemiacetal hydroxyl group. The most famous substances of this type are sucrose and trehalose.

These compounds are widespread in nature. They can be found both in free form and in other compounds. Disaccharides are a source of energy, since glucose is formed from them during hydrolysis.

Lactose is very important for children, as it is the main component baby food... Another function of this type of carbohydrates is structural, since they are part of the cellulose, which is needed for the formation of plant cells.

Characteristics and features of polysaccharides

Another type of carbohydrate is polysaccharides. This is the most difficult type of connection. They consist of a large number of monosaccharides (their main component is glucose). In the gastrointestinal tract, polysaccharides are not absorbed - they are preliminarily broken down.

The features of these substances are as follows:

insolubility (or poor solubility) in water;
yellowish color (or no color);
they have no smell;
almost all of them are tasteless (some have a sweetish taste).

The chemical properties of these substances include hydrolysis, which is carried out under the influence of catalysts. The result of the reaction is the breakdown of the compound into structural elements - monosaccharides.

Another property is the formation of derivatives. Polysaccharides can react with acids.

The products formed during these processes are very diverse. These are acetates, sulfates, esters, phosphates, etc.

Examples of polysaccharides:

starch;
cellulose;
glycogen;
chitin.

Educational video about the functions and classification of carbohydrates:

These substances are important for the full functioning of the body as a whole and cells separately. They supply the body with energy, participate in the formation of cells, protect internal organs from damage and adverse effects. They also play the role of reserve substances that animals and plants need in case of a difficult period.

Disaccharides enter into most of the reactions characteristic of monosaccharides: they form ethers and esters, glycosides, derivatives of the carbonyl group. Reducing disaccharides are oxidized to glycobionic acids. The glycosidic bond in disaccharides is cleaved under the action of aqueous solutions of acids and enzymes. Disaccharides are stable in dilute alkali solutions. Enzymes act selectively, cleaving only? - or only? -Glycosidic bond / 6 /.

The sequence of reactions - oxidation, methylation, hydrolysis, makes it possible to establish the structure of the disaccharide (Fig. 7).

Rice. 7

Oxidation makes it possible to determine which monosaccharide residue is located at the reducing end. Methylation and hydrolysis provide information about the position of the glycosidic bond and the size of the cycle of monosaccharide units. The configuration of the glycosidic bond (?? or ?? can be determined by enzymatic hydrolysis / 1 /.

The biological role of disaccharides

Sucrose in the gastrointestinal tract breaks down into glucose and fructose. Sucrose is the most abundant sugar. Sources of sucrose: sugar beet (14-18%) and sugar cane (10-15%). Sucrose content: in granulated sugar - 99.75%, in refined sugar - 99.9%.

Sucrose has the ability to turn into fat. Excessive intake of this carbohydrate in the diet causes a violation of fat and cholesterol metabolism in the human body, has a negative effect on the state and function intestinal microflora increasing specific gravity putrefactive microflora, increasing the intensity of putrefactive processes in the intestine, leads to the development of intestinal flatulence. An excessive amount of sucrose in the diet of children leads to the development of dental caries.

Lactose is an animal carbohydrate. During hydrolysis, it breaks down into glucose and galactose. Hydrolysis proceeds slowly, limiting the fermentation process, which has great importance in the nutrition of infants. The intake of lactose into the body contributes to the development of lactic acid bacteria, which suppress the development of putrefactive microorganisms. Lactose is least used for fat formation and, in excess, does not increase blood cholesterol. Source of lactose: milk and dairy products, in which the content of this disaccharide can reach 4-6%.

Sucrose, lactose and maltose are valuable food and flavoring substances. The sugar industry is engaged in the production of sucrose.

Cellobiose disaccharide is essential for plant life, as it is part of cellulose / 4 /.

sucrose glycosidic chemical disaccharide

Disaccharides: sucrose, lactose, maltose, etc. are widespread and important as components of food products.

In terms of chemical structure, disaccharides are glycosides of monosaccharides. Most disaccharides are composed of hexoses, but in nature disaccharides are known, consisting of one hexose molecule and one pentose molecule.

Maltose- reserve oligosaccharide - found in many plants in small quantities, in large quantities accumulates in malt - usually in barley seeds germinated under certain conditions. This is why maltose is often referred to as malt sugar. Maltose is formed in plant and animal organisms as a result of starch hydrolysis by amylases.

Maltose contains two D-glucopyranose residues linked by a (1®4) glycosidic bond.

Maltose has reducing properties, which is used in its quantitative determination. It is readily soluble in water. The solution shows mutarotation.

Under the action of the enzyme α-glucosidase (maltase), malt sugar is hydrolyzed to form two glucose molecules:

Maltose is fermented by yeast. This ability of maltose is used in fermentation technology for the production of beer, ethyl alcohol, etc. from starch-containing raw materials.

Lactose is hydrolyzed by the enzyme b-galactosidase (lactase):

Lactose differs from other sugars in the absence of hygroscopicity - it does not damp. Milk sugar is used as a pharmaceutical and as a nutritional supplement for infants. Aqueous solutions of lactose mutarotate, lactose has a 4-5 times less sweet taste than sucrose.

Sucrose consists of a-D-glucopyranose and b-D-fructofuranose linked by an a-1 → b-2-bond due to glycosidic hydroxyls:

Sucrose does not contain free hemiacetal hydroxyl; therefore, it is not capable of oxy-oxo-tautomerism and is a non-reducing disaccharide.

Carbohydrates formed by the remains of two monosaccharides. Disaccharides are widespread in animals and plants: sucrose, lactose, maltose, trehalose ... Big Encyclopedic Dictionary

DISACHARIDES, a type of sugar (which includes food sugar), formed by the condensation of two MONOSACCHARIDES with the removal of water. Cane sugar (sucrose) is a disaccharide that, when HYDROLYSIS in the presence of acid, gives ... ... Scientific and technical encyclopedic dictionary

DISACHARID- (sugar-like polioses, bios), carbohydrates, which are cleaved during hydrolysis (inversion) with the formation of 1 molecule D. 2 molecules of monos. D. are soluble in water, giving true solutions; most crystallize well, have a sweet taste. Leftovers ... ... Great medical encyclopedia

Bioses, oligosaccharides, molecules are built from two monosaccharide residues linked by a glycosidic bond. In non-reducing D. (sucrose, trehalose), both glycosidic hydroxyls are involved in the formation of bonds between monosaccharides, in ... ... Biological encyclopedic dictionary

BIOSES are oligosaccharides, the molecules of which are built of two monosaccharide residues linked by a glycosidic bond. In non-reducing D. (sucrose, trehalose), both glycosidic hydroxyls are involved in the formation of bonds between monosaccharides, in ... ... Microbiology Dictionary

Carbohydrates formed by the remains of two monosaccharides. Disaccharides are widespread in animals and plants: sucrose, lactose, maltose, trehalose. * * * Disaccharides Disaccharides, carbohydrates formed by the remains of two monosaccharides. V… … encyclopedic Dictionary

- (gr. di (s) twice + sakchar sugar + eidos kind) a class of organic compounds, carbohydrates, the molecules of which consist of two monosaccharide residues; the most important representatives disaccharides sucrose and lactose. New dictionary foreign words... by EdwART,…… Dictionary of foreign words of the Russian language

- (syn. biose) complex sugars, consisting of two residues of monosaccharides; are the main sources of carbohydrates in human and animal nutrition (lactose, sucrose, etc.) ... Comprehensive Medical Dictionary

Bioses, carbohydrates, the molecules of which consist of two residues of monosaccharides (See. Monosaccharides). All D. are built according to the type of glycosides (see. Glycosides). In this case, the hydrogen atom of the glycoside hydroxyl of one monosaccharide molecule is replaced ... ... Great Soviet Encyclopedia

Same as sucrobioses, see Hydrates of carbon ... Encyclopedic Dictionary of F.A. Brockhaus and I.A. Efron

Books

,. The collective monograph offered to the reader summarizes the scientific achievements of the last decade in the field of carbohydrate chemistry. For the first time, the features of the structure are considered in interconnection, ...
Scientific foundations of the chemical technology of carbohydrates, Zakharov AG .. The collective monograph offered to the reader summarizes the scientific achievements of the last decade in the field of carbohydrate chemistry. For the first time, the features of the structure are considered in interconnection, ...

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