To widespread and important as components of food products include disaccharides: sucrose, lactose, maltose, etc.

The chemical structure of Disaccharides are glycosides of monosaccharides. Most disaccharides consist of hexose, but in nature disaccharides, consisting of one hexose molecule and one pentose molecule.

In the formation of a disaccharide, one monosaccharide molecule always forms a connection with the second molecule using its semi-acetal hydroxyl. Another monosaccharide molecule can be connected either by half acetal hydroxyl, or one of the alcohol hydroxyls. In the latter case, one semi-acetal hydroxyl will remain free in the disaccharide molecule.

Maltose - Reserve oligosaccharide - found in many plants in small quantities, accumulates in the malt in large quantities - usually in barley seeds, sprouted under certain conditions. Therefore, maltose is often called malt sugar. Maltose is formed in plant and animal organisms as a result of starch hydrolysis under the action of amilas.

Maltose contains two residues of d-glucopyranose, interconnected by a (1®4) glycoside bond.

Maltose has restoring properties, which is used in its quantitative determination. It is easily soluble in water. The solution detects mutating.

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

Maltose ferments fermented. This maltose ability is used in the technology of fermentation industries in 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 crushed industry from the dairy serum after the branch of the cottage cheese. It is fermented only by special lactose yeast contained in kefir and kumys. Lactose is constructed from B-D-galactopyranose residues and A-D-glucopyranose, interconnected B- (1 → 4) -Hlikosoid bond. Lactose is a reducing disaccharide, and the free semi-acetal hydroxyl belongs to the glucose residue, and the oxygen bridge binds the first carbon atom of the galactose residue with the fourth carbon atom of the glucose residue.

Lactose is hydrolyzed under the action of B-galactosidase enzyme (lactase):

Lactose is different from other sugars in the absence of hygroscopicity - it does not rely. Milk sugar is used as a pharmaceutical preparation and as a nutrient for infants. Aqueous lactose solutions mutimated, lactose has 4-5 times less sweet taste than sucrose.

Sakhares (reed sugar, beet sugar) is a reserve disaccharide - is extremely widespread in plants, especially its beets in rootfalls (from 14 to 20%), as well as in sugar cane stems (from 14 to 25%). Sakhares is a vehicle sugar, in the form of which carbon and energy are transported by a plant. It is in the form of sucrose that carbohydrates move from the synthesis sites (leaves) to the place where they are deposited into the reserve (fruits, root, seeds).

The sucrose consists of A-D-glucopyranose and B-d-fructufuransza, connected by A-1 → B-2-bond due to glycosidic hydroxyls:

Sacraosis does not contain free semi-acetal hydroxyl, so it is not capable of oxi-tautomeria and is a non-refining disaccharide.

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

The most important disaccharides - Sakhares, Maltosis and Lactose. All of them have a general formula C12N22O11, but their structure is different.

Sakhares Consists of 2x cycles interconnected due to glycoside hydroxide:

Maltoseconsists of 2 glucose residues:

Lactose:

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

Chemical properties of disaccharides.

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

Restoring dicarides - maltose and lactose. They react with ammonia silver oxide solution:

Copper (II) hydroxide (II) can be restored to copper oxide (I):

The reduction capacity is explained by the cyclicity of the shape and the content of glycosidic hydroxyl.

In sucrose there is no glycosidic hydroxyl, so the cyclic form cannot be revealed and move into aldehyde.

Application of disaccharides.

The most common disaccharide is sucrose.

Disaccharides (maltose, lactose, sucrose)

This is the source of carbohydrates in human food.

Lactose is contained in milk and is obtained from it.

Maltose is contained in the sprouted seeds of bread cereals and is formed with the enzymatic hydrolysis of starch.

Additional materials on the topic: Disaccharides. Properties of disaccharides.

Restoring disaccharides

Maltose or malt sugar belongs to the number of regenerating disaccharides. Maltose is obtained with partial hydrolysis of starch in the presence of enzymes or an aqueous acid. Maltose is constructed of two glucose molecules (i.e. it is glucoside). Glucose is present in maltose in the form of a cyclic semi-aotic. Moreover, the bond between the two cycles form a glycoside hydroxyl of one molecule and the fourth tetrahedron hydroxyl. The feature of the structure of Maltose molecule is that it is constructed from α-anelomers of glucose:

The presence of free glycosidic hydroxyl causes the main properties of Maltose:

Disaccharides

Ability to Tautomeria and Mutarotes:

Maltose can oxidize and recover:

For restoring disaccharide, you can get phenylhydrange and ozazon:

Regenerating disaccharide can be alkyl with methyl alcohol in the presence of hydrogen chloride:

Regardless of that restoring or not restoring - disaccharide can be alkylated by iodide methyl in the presence of wet silver oxide or acetylated acetic anhydride. At the same time, all hydroxyl groups of disaccharide are entering the reaction:

Another product of the Higher Polysaccharide Hydrolysis is Disaccharide Cellobiosis:

Cellobiosis, as well as maltose constructed from two glucose residues. The principal difference is that in the molecule of cellobiosis residues are associated with β-glycosidic hydroxyl.

Judging by the structure of the cellobioma molecule, it should be reducing sugar. She is also inherent in all chemical properties of disaccharides.

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

Lactose is inherent in all properties of restoring sugars: Tautomeria, mutrization, oxidation to lactobionic acid, recovery, formation of hydrazones and ozones.

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Question 2. Disaccharides

The formation of glycosides

Glycosidial relationship is important, because it is precisely with the help of this connection a covalent binding of monosaccharides in the composition of oligo and polysaccharides is carried out. When the glycosidic communication is formed, an anomeric group of one monosaccharide interacts with a group of another monosaccharide or alcohol. In this case, the cleavage of water and education is cleaving O-glycoside. All linear oligomers (except disaccharides) or polymers contain monomeric residues involved in the formation of two glycoside bonds, except for terminal residues. Some glycosida residues can form three glycosida links, which is typical of branched oligo and polysaccharides. Oligo and polysaccharides may have a terminal residue of monosaccharide with a free anomeric ON-group, not used in the formation of a glycoside. In this case, when the cycle is blurred, the formation of a free carbonyl group capable of oxidation is possible. Such oligo and polysaccharides have reducing properties and therefore are called restoring or reducing.

Figure is the structure of polysaccharide.

A. Education A-1,4 - and A-1,6-glycosidic ties.

B. Building linear polysaccharide:

1 - a-1,4-glycoside ties between the mannel;

2 - not restoring the end (there is no formation of a free carbonyl group in anomeric carbohydrate);

3 is a regenerating end (possibly opening a cycle to form a free carbonyl group in anomeric carbon).

Anomaneous monosaccharide group can interact with the NH2 group of other compounds, which leads to the formation of N-glycoside. Such a link is present in nucleotides and glycoproteins.

Figure - structure n-glycoside

Question 2. Disaccharides

Oligosaccharides contain from two to ten residues of monosaccharides, connected by a glycoside bond. Disaccharides are the most common oligomeric carbohydrates, found in free form, i.e. Not related to other connections. In the chemical nature of disaccharides are glycosides that contain 2 monosaccharide, connected by glycosidic bond in A- or B-configuration. The food contains mainly such disaccharides like sucrose, lactose and maltose.

Figure - Disaccharides Food

Sucrose -disaccharide consisting of A-D-glucose and B-D-fructose, connected A, B-1,2-glycoside. In sucrose, both domestic on-groups of glucose and fructose residual groups are involved in the formation of glycoside. Consequently, Sakhares does not apply to restoring sugars. Sakharoza is a soluble disaccharide with a sweet taste.

Disaccharides. Properties of disaccharides.

The source of sucrose is plants, especially sugar branches, sugar cane. The latter explains the occurrence of the trivial name of sucrose - "reed sugar".

Lactose - Milk sugar. Lactose is hydrolyzed to form glucose and galactose. The most important disaccharide milk mammals. The cow's milk contains up to 5% lactose, in a feminine - up to 8%. In the lactose, the anomeric ON-group of the first carbon atom of the D-galactose residue is associated with a b-glycosidic bond with a fourth carbon d-glucose atom (B-1,4-Communication). Since the anomeric carbon atom of the glucose residue does not participate in the formation of glycoside, therefore lactose refers to restoring sugars.

Maltosecomes with products containing partially hydrolyzed starch, for example, malt, beer. Maltose is formed when the starch is cleavage in the intestine and partly in the oral cavity. Maltose consists of two D-glucose residues connected by A-1,4-glycoside. Refers to restoring sugars.

Question 3. Polysaccharides:

Classification

Depending on the structure of residues of monosaccharides, polysaccharides can be divided into homopolisaccharides (All monomers are identical) and heteropolisaccharides (Monomers are different). Both types of polysaccharides may have both the linear location of monomers and branched.

The following structural differences between polysaccharides are distinguished:

• the structure of monosaccharides constituting the chain;
• type of glycoside bonds connecting monomers in the chain;
• the sequence of monosaccharide residues in the chain.

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

• backup polysaccharides performing energy function. These polysaccharides serve as a source of glucose used by the body as needed. The backup function of carbohydrates is ensured by their polymeric nature. Polysaccharides harder solublethan monosaccharides, therefore, they do not affect the osmotic pressure and therefore, they can accumulate in the cell, for example, starch - in plants cells, glycogen - in animal cells;
• structural polysaccharides providing cells and organs mechanical strength;
• polysaccharides that are part of the intercellular matrix, participate in the formation of tissues, as well as in proliferation and differentiation of cells. The polysaccharides of the intercellular matrix water-soluble and are strongly hydrated.

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Structural formula

Molecular weight: 342,297

Maltose (from English Malt - malt) - malt sugar, 4-o-α-D-glucopyranosyl-D-glucose, natural disaccharide, consisting of two glucose residues; It is contained in large quantities in the sprouted grains (malt) barley, rye and other grains; It was also discovered in tomatoes, in pollen and nectar of a row of plants.
Maltose biosynthesis from β-D-glucopyranosyl phosphate and D-glucose is known only in some types of bacteria. In the animal and vegetable organisms, maltose is formed in the enzymatic cleavage of starch and glycogen (see amylases).
Maltose is easily absorbed by the human body. The splitting of maltose up to two glucose residues occurs as a result of the action of the enzyme A-glucosidase, or malalhaz, which is contained in the digestive juices of animals and humans, in the sprouted grain, in mold mushrooms and yeast. The genetically determined absence of this enzyme in the mucous membrane of the human intestine leads to the congenital intolerance to maltose - a difficult disease that requires exceptions from the diet of maltose, starch and glycogen or addition to the Food enzyme material.

Chemical name

α-maltosis - (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) oxan-2,3,4-triol

Physical properties

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

(from English Malt ≈ malt), malt sugar, natural disaccharide, consisting of two glucose residues; It is contained in large quantities in the sprouted grains (malt) barley, rye and other grains; It was also discovered in tomatoes, in pollen and nectar of a row of plants. M. Easy soluble in water, has a sweet taste; It is reducing sugar, as it has an unsubstituted semi-aceteal hydroxyl group. Bosynthesis M. from B-D-glucopyranosyl phosphate and D-glucose is known only in some types of bacteria. In the animal and vegetable organisms of M.

it is formed during the enzymatic cleavage of starch and glycogen (see amylases). The splitting of M. up to two glucose residues occurs as a result of the action of the enzyme A-glucosidase, or moaltase, which is contained in the digestive juices of animals and humans, in the sprouted grain, in mold mushrooms and yeast. The genetically determined absence of this enzyme in the mucous membrane of the human intestine leads to the congenital intolerance of M. ≈ a severe disease that requires exclusion from the diet of M., starch and glycogen or addition to the Food enzyme.

Lit.: Chemistry of carbohydrates, M., 1967; Harris, the basics of the biochemical human genetics, translation from English, M., 1973.

One of the varieties of 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. It should be understood what they need and what are their chemical and physical properties.

Carbohydrates are called compounds, which contains carbon, hydrogen and oxygen. Most often they have natural origins, although some are created industrially. Their role in the vital activity of living organisms is enormous.

The main functions are called the following:

1. Energy. These compounds are the main source of energy. Most of the organs can fully work at the expense of the energy obtained during glucose oxidation.
2. Structural. Carbohydrates are necessary for the formation of almost all cells of the body. The fiber plays the role of the support material, and in the bones and cartilage tissue are carbohydrates of complex type. One of the components of cell membranes is hyaluronic acid. Also, carbohydrate compounds are required in the process of generating enzymes.
3. Protective. When functioning the body, it is possible to work with glands that allocate secretory fluids, which are necessary to protect the internal organs from pathogenic effects. A significant part of these liquids is represented by carbohydrates.
4. Regulatory. This function is manifested in the effect on the human body of glucose (maintains homeostasis, controls osmotic pressure) and fiber (affects the gastrointestinal peristaltics).
5. Special functions. They are peculiar to certain types of carbohydrates. Such special functions include: participation in the process of 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 features.

This is true, and their main classification includes such varieties as:

1. . They are considered the most simple. The remaining types of carbohydrates enter the hydrolysis process and disintegrate into smaller components. Monosaccharides there are no such ability, they are a final product.
2. Disaccharides. In some classifications, they are related to oligosaccharides. There are two monosaccharide molecules in their composition. It is for them that the disaccharide is divided into hydrolysis.
3. Oligosaccharida. The composition of this compound is from 2 to 10 molecules of monosaccharides.
4. Polysaccharides. These compounds are the largest variety. They include more than 10 molecules of monosaccharides.

Each type of carbohydrate has its own characteristics. It is necessary to consider them to understand how each of them affects the human body and what is its benefit.

These compounds are the simplest form of carbohydrates. There is one molecule in their composition, so during hydrolysis does not make their division into small blocks. When combining monosaccharides, disaccharides, oligosaccharides and polysaccharides are formed.

They are distinguished by a solid aggregate condition and sweet taste. They have the ability to dissolve in water. They can also be dissolved in alcohols (the reaction is weaker than with water). Monosaccharides almost do not react to mixing with ether.

Most often mention natural monosaccharides. Some of them people consume together with food. These include glucose, fructose and galactose.

• chocolate;
• fruit;
• some types of wine;
• syrups, etc.

The main function of carbohydrates of this type is the energy. It cannot be said that the body cannot do without them, but they have properties important for the body's full-fledged work, for example, participation in metabolic processes.

Monosaccharides The body absorbs the faster thing that happens in the gastrointestinal tract. The process of assimilation of complex carbohydrates, unlike simple compounds, is not so simple. First, complex compounds should be divided to monosaccharides, only after that they are absorbed.

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

Glucose provides muscle and brain tissue cells. If in contact with the body, the substance is absorbed, enters the blood and spreads throughout the body. It occurs its oxidation with the release of energy. This is the main source of energy feeding for the brain.

With a shortage of glucose in the body, hypoglycemia develops, which is primarily reflected in the functioning of brain structures. However, excessive content in the blood is also dangerous, as it leads to the development of diabetes. Also, when using a large amount of glucose, the body weight begins to increase.

Fructose

It refers to the number of monosaccharides and is very similar to glucose. It has a slower pace of assimilation. This is explained by the fact that for assimilation it is necessary that fructose first transformed into glucose.

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

Fructose has the ability to quickly transform into fatty acids, which causes the development of obesity. Also, due to this compound, the sensitivity to insulin is reduced, which causes type 2 diabetes.

This substance can be obtained from berries and fruits, and more from honey. It is usually located there in combination with glucose. The connection is also inherent white. Taste is sweet, and this feature is more intense than in the case of glucose.

Other connections

There are other monosaccharide compounds. They can be natural and half-art.

Natural belongs to Galactose. It is also contained in food, but does not occur in its pure form. Galactose is the result of lactose hydrolysis. Its main source is called milk.

Other natural monosaccharides are robose, deoxyribosis and mannose.

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

These substances are also in food and fall into the human body:

• ramunoza;
• eritround;
• ribulose;
• D-xylose;
• L-alloza;
• D-sorbiz, etc.

Each of these compounds is characterized by its features and functions.

Disaccharides and their application

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

This type of carbohydrate is characterized by the following features:

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

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

2 types of such compounds are found:

1. Restoring. Their feature is the presence of a free semi-acetal hydroxyl group. Due to it, such substances have rehabilitation properties. This group of carbohydrates includes cellobiosis, maltose and lactose.
2. Non-establishing. These compounds have no opportunity to restore, since they do not have a semi-acetal hydroxyl group. The most famous substances of this type are sucrose and trehalosis.

These compounds are widespread in nature. They can occur both in free form and as part of other compounds. Disaccharides are an energy source, since glucose is formed during hydrolysis.

Lactose is very important for children, since it is the main one of the components of baby food. Another function of carbohydrates of this type is structural, since they are part of cellulose, which is needed to form vegetable cells.

Characteristics and features of polysaccharides

Another type of carbohydrates are polysaccharides. This is the most complex type of compounds. They consist of a large number of monosaccharides (their main component - glucose). The polysaccharides are not absorbed in the tract gastrointestinal tract - their splitting is performed.

The features of these substances are:

• insoluability (or weak solubility) in water;
• the color is yellowish (or color is missing);
• they have no smell;
• almost all of them are tasteless (some have a sweet taste).

The chemical properties of these substances belongs to hydrolysis, which is carried out under the influence of catalysts. The result of the reaction becomes the decay of the connection on the structural elements - monosaccharides.

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

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

Examples of polysaccharides:

• starch;
• cellulose;
• glycogen;
• chitin.

Educational video material on the functions and classification of carbohydrates:

These substances are important for the full functioning of the body entirely and cells separately. They supply the body with energy, participate in cell formation, protected internal organs from damage and adverse effects. They also play the role of spares that are needed by animals and plants in case of a complex period.

Disaccharides enter the majority of reactions characteristic of monosaccharides: form simple and esters, glycosides derived by carbonyl group. Restoring disaccharides are oxidized to glycobionic acids. The glycoside bond in disaccharides is split under the influence of aqueous solutions of acids and enzymes. In dilute solutions of alkalis, disaccharides are stable. Enzymes act selectively, splitting only? - Or just? -Hlikosida / 6 /.

The sequence of reactions - oxidation, methylation, hydrolysis, allows you to set the structure of the disaccharide (Fig. 7).

Fig. 7.

Oxidation makes it possible to determine the balance of which monosaccharide is on the regenerating end. Methylation and hydrolysis provide information on the position of the glycoside and the size of the monosaccharide cycle. The configuration of the glycoside (?? or ?? can be determined by enzymatic hydrolysis / 1 /.

The biological role of Disacharid

Sakharoza in the gastrointestinal tract disintegrates on glucose and fructose. Sakhares - the most common sugar. Sources of sucrose: sugar beet (14-18%) and sugar cane (10-15%). The content of sucrose: in sugar sand - 99.75%, in Sahara Rafinade - 99.9%.

Sakhares has the ability to turn into fat. The excess receipt of this carbohydrate in the food diet causes a violation of fat and cholesterol exchange in the human body, has a negative effect on the state and function of intestinal microflora, increasing the proportion of rotten microflora, enhancing the intensity of rotary processes in the intestine leads to the development of intestinal meteorism. The excess amount of sucrose in the nutrition of children leads to the development of caries of teeth.

Lactose - carbohydrate of animal origin. In hydrolysis, glucose and galactose is split. The hydrolysis takes place slowly, limiting the fermentation process, which is of great importance in the nutrition of breast-age. The admission of lactose into the body contributes to the development of lactic acid bacteria, overwhelming the development of rotary microorganisms. Lactose in the smallest extent is used for fat formation and during excess does not increase the cholesterol content in the blood. Source of lactose: Milk and dairy products in which the content of this disaccharide can reach 4-6%.

Sakhares, lactose and maltose - valuable food and flavoring substances. The production of sucrose is occupied by the sugar industry.

Disaccharide Cellobiosis is important for the life of plants, as it is part of cellulose / 4 /.

sacraosis Glycoside Chemical Disaccharide

To widespread and important as components of food products include disaccharides: sucrose, lactose, maltose, etc.

The chemical structure of Disaccharides are glycosides of monosaccharides. Most disaccharides consist of hexose, but in nature disaccharides, consisting of one hexose molecule and one pentose molecule.

In the formation of a disaccharide, one monosaccharide molecule always forms a connection with the second molecule using its semi-acetal hydroxyl. Another monosaccharide molecule can be connected either by half acetal hydroxyl, or one of the alcohol hydroxyls. In the latter case, one semi-acetal hydroxyl will remain free in the disaccharide molecule.

Maltose - Reserve oligosaccharide - found in many plants in small quantities, accumulates in the malt in large quantities - usually in barley seeds, sprouted under certain conditions. Therefore, maltose is often called malt sugar. Maltose is formed in plant and animal organisms as a result of starch hydrolysis under the action of amilas.

Maltose contains two residues of d-glucopyranose, interconnected by a (1®4) glycoside bond.

Maltose has restoring properties, which is used in its quantitative determination. It is easily soluble in water. The solution detects mutating.

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

Maltose ferments fermented. This maltose ability is used in the technology of fermentation industries in 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 crushed industry from the dairy serum after the branch of the cottage cheese. It is fermented only by special lactose yeast contained in kefir and kumys. Lactose is constructed from B-D-galactopyranose residues and A-D-glucopyranose, interconnected B- (1 → 4) -Hlikosoid bond. Lactose is a reducing disaccharide, and the free semi-acetal hydroxyl belongs to the glucose residue, and the oxygen bridge binds the first carbon atom of the galactose residue with the fourth carbon atom of the glucose residue.

Lactose is hydrolyzed under the action of B-galactosidase enzyme (lactase):

Lactose is different from other sugars in the absence of hygroscopicity - it does not rely. Milk sugar is used as a pharmaceutical preparation and as a nutrient for infants. Aqueous lactose solutions mutimated, lactose has 4-5 times less sweet taste than sucrose.

Sakhares (reed sugar, beet sugar) is a reserve disaccharide - is extremely widespread in plants, especially its beets in rootfalls (from 14 to 20%), as well as in sugar cane stems (from 14 to 25%). Sakhares is a vehicle sugar, in the form of which carbon and energy are transported by a plant. It is in the form of sucrose that carbohydrates move from the synthesis sites (leaves) to the place where they are deposited into the reserve (fruits, root, seeds).

The sucrose consists of A-D-glucopyranose and B-d-fructufuransza, connected by A-1 → B-2-bond due to glycosidic hydroxyls:

Sacraosis does not contain free semi-acetal hydroxyl, so it is not capable of oxi-tautomeria and is a non-refining disaccharide.

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

Carbohydrates formed by the remains of two monosaccharides. In animals and vegetable organisms, disaccharides are common: sucrose, lactose, maltose, trehalosis ... Big Encyclopedic Dictionary

Disaccharides, the type of sugar (to which the food sugar belongs to both the condensation of two monosaccharides with water removal. Reed sugar (sucrose) is a disaccharide, which in hydrolysis in the presence of an acid gives ... ... Scientific and Technical Encyclopedic Dictionary

Disaccharides - (sugar-like polyo, biose), carbohydrates that are splitting with hydrolysis (inversion) to form from 1 molecule by D. 2 monosa molecules. D. soluble in water, giving true solutions; Most is well crystallized, has a sweet taste. Rest ... ... Big medical encyclopedia

Biosis, oligosaccharides, molecules to rye are constructed of two monosaccharide residues associated with glycoside bond. In non-standard D. (Sakharoza, Tregaloz) in the formation of communication between monosaccharides, both glycosidic hydroxyl are occupied, in ... ... Biological Encyclopedic Dictionary

Biosis - oligosaccharides, whose molecules are built of two monosaccharide residues associated with glycosidic bond. In non-standard D. (Sakharoza, Tregaloz) in the formation of communication between monosaccharides, both glycosidic hydroxyl are occupied, in ... ... Dictionary of microbiology

Carbohydrates formed by the remains of two monosaccharides. In animals and vegetable organisms, disaccharides are common: sucrose, lactose, maltose, trehalosis. * * * Disaccharides of disaccharides, carbohydrates formed by the remnants of two monosaccharides. AT… … encyclopedic Dictionary

- (c. di (s) twice + sakchar sugar + eidos view) class of organic compounds, carbohydrates whose molecules consist of two monosaccharide residues; The most important representative of Disaccharides Sakhares and Lactose. New dictionary of foreign words. By Edwart, ... ... Dictionary of foreign words of the Russian language

- (Xin. Biosis) Sugar sugars consisting of two monosaccharide residues; are the main sources of carbohydrates in human and animal nutrition (lactose, sucrose, etc.) ... Big Medical Dictionary

Biosis, carbohydrates, whose molecules consist of two monosaccharide residues (see monosaccharides). All D. are built by type of glycosides (see glycosides). At the same time, the hydrogen atom of the glycosidic hydroxyl of one monosaccharide molecule is replaced ... ... Great Soviet Encyclopedia

The same as sugar carbon hydrates, see carbon hydrates ... Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron

Books

• . The collective monograph proposed by the reader summarizes the scientific achievements of the last decade in the field of carbohydrate chemistry. For the first time in relationships are considered the features of the structure, ...
• Scientific bases of chemical technology of carbohydrates, Zakharov AG. The collective monograph proposed by the reader summarizes the scientific achievements of the last decade in the field of carbohydrate chemistry. For the first time in relationships are considered the features of the structure, ...