Sucrose C12H22O11, or beet sugar, cane sugar, in everyday life is simply sugar - a disaccharide consisting of two monosaccharides - α-glucose and β-fructose.
Sucrose is a very common disaccharide in nature, it is found in many fruits, fruits and berries. The content of sucrose is especially high in sugar beet and sugar cane, which are used for the industrial production of edible sugar.
Colorless monoclinic crystals. When the molten sucrose solidifies, an amorphous transparent mass is formed - caramel.
Molecular weight 342.3 a.m.u.
The taste is sweetish. Solubility (grams per 100 grams): in water 179 (0°C) and 487 (100°C), in ethanol 0.9 (20°C). Slightly soluble in methanol. Insoluble in diethyl ether
Density 1.5879 g/cm3
When cooled with liquid air, after illumination with bright light, sucrose crystals phosphoresce
Does not show reducing properties - does not react with Tollens' reagent and Fehling's reagent.
Among the isomers of sucrose having the molecular formula C12H22O11, maltose and lactose can be distinguished
If you boil a solution of sucrose with a few drops of hydrochloric or sulfuric acid and neutralize the acid with alkali, and then heat the solution, molecules with aldehyde groups appear, which reduce copper (II) hydroxide to copper (I) oxide. This reaction shows that sucrose undergoes hydrolysis under the catalytic action of the acid, resulting in the formation of glucose and fructose:
С12Н22О11 + Н2О → С6Н12O6 + С6Н12O6
Natural and anthropogenic sources
Contained in sugar cane, sugar beet (up to 28% dry matter), plant juices and fruits (eg birch, maple, melon and carrot). The source of sucrose - from beets or cane - is determined by the ratio of the content of stable carbon isotopes 12C and 13C. Sugar beet has a C3 carbon dioxide uptake mechanism (via phosphoglyceric acid) and preferentially absorbs the 12C isotope; Sugar cane has a C4 carbon dioxide absorption mechanism (through oxaloacetic acid) and preferentially absorbs the 13C isotope.
1. It is a colorless crystals of sweet taste, highly soluble in water.
2. The melting point of sucrose is 160 °C.
3. When molten sucrose solidifies, an amorphous transparent mass is formed - caramel.
4. Contained in many plants: birch sap, maple, carrots, melons, as well as sugar beet and sugar cane.
Structure and chemical properties.
1. The molecular formula of sucrose is C 12 H 22 O 11.
2. Sucrose has a more complex structure than glucose.
3. The presence of hydroxyl groups in the sucrose molecule is easily confirmed by the reaction with metal hydroxides.
If a solution of sucrose is added to copper (II) hydroxide, a bright blue solution of copper sucrose is formed.
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.
6. Sucrose is the most important of the disaccharides.
7. It is obtained from sugar beet (it contains up to 28% of sucrose from dry matter) or from sugar cane.
Reaction of sucrose with water.
If you boil a solution of sucrose with a few drops of hydrochloric or sulfuric acid and neutralize the acid with alkali, and then heat the solution with copper (II) hydroxide, a red precipitate will form.
When boiling a sucrose solution, molecules with aldehyde groups appear, which reduce copper (II) hydroxide to copper (I) oxide. This reaction shows that sucrose undergoes hydrolysis under the catalytic action of the acid, resulting in the formation of glucose and fructose:
C 12 H 22 O 11 + H 2 O → C 6 H 12 O 6 + C 6 H 12 O 6.
6. The sucrose molecule consists of glucose and fructose residues connected to each other.
Among the isomers of sucrose having the molecular formula C 12 H 22 O 11, maltose and lactose can be distinguished.
Features of maltose:
1) maltose is obtained from starch under the action of malt;
2) it is also called malt sugar;
3) upon hydrolysis, it forms glucose:
C 12 H 22 O 11 (maltose) + H 2 O → 2C 6 H 12 O 6 (glucose).
Features of lactose: 1) lactose (milk sugar) is found in milk; 2) it has a high nutritional value; 3) upon hydrolysis, lactose decomposes into glucose and galactose, an isomer of glucose and fructose, which is an important feature.
66. Starch and its structure
Physical properties and presence in nature.
1. Starch is a white powder, insoluble in water.
2. In hot water, it swells and forms a colloidal solution - a paste.
3. As a product of the assimilation of carbon monoxide (IV) by green (containing chlorophyll) plant cells, starch is common in the plant world.
4. Potato tubers contain about 20% starch, wheat and corn grains - about 70%, rice - about 80%.
5. Starch is one of the most important nutrients for humans.
The structure of starch.
1. Starch (C 6 H 10 O 5) n is a natural polymer.
2. It is formed as a result of the photosynthetic activity of plants when absorbing the energy of solar radiation.
3. First, glucose is synthesized from carbon dioxide and water as a result of a number of processes, which in general can be expressed by the equation: 6CO 2 + 6H 2 O \u003d C 6 H 12 O 6 + 6O 2.
5. Starch macromolecules are not the same in size: a) they include a different number of C 6 H 10 O 5 units - from several hundred to several thousand, while their molecular weight is not the same; b) they also differ in structure: along with linear molecules with a molecular weight of several hundred thousand, there are branched molecules with a molecular weight of several million.
Chemical properties of starch.
1. One of the properties of starch is the ability to give a blue color when interacting with iodine. This color is easy to observe if you place a drop of iodine solution on a slice of potato or a slice of white bread and heat the starch paste with copper (II) hydroxide, the formation of copper (I) oxide will be visible.
2. If you boil the starch paste with a small amount of sulfuric acid, neutralize the solution and react with copper (II) hydroxide, a characteristic precipitate of copper (I) oxide forms. That is, when heated with water in the presence of an acid, starch undergoes hydrolysis, and a substance is formed that reduces copper (II) hydroxide to copper (I) oxide.
3. The process of splitting starch macromolecules with water is gradual. First, intermediate products with a lower molecular weight than starch are formed - dextrins, then the sucrose isomer - maltose, the end product of hydrolysis is glucose.
4. The reaction of the conversion of starch into glucose under the catalytic action of sulfuric acid was discovered in 1811 by a Russian scientist K. Kirchhoff. The method he developed for obtaining glucose is still used today.
5. Starch macromolecules consist of residues of cyclic L-glucose molecules.
Scientists have proven that sucrose is an integral part of all plants. The substance is found in large quantities in sugar cane and sugar beets. The role of this product is quite large in the diet of every person.
Sucrose belongs to the group of disaccharides (included in the class of oligosaccharides). Under the action of its enzyme or acid, sucrose breaks down into fructose (fruit sugar) and glucose, of which most polysaccharides are composed.
In other words, sucrose molecules are made up of D-glucose and D-fructose residues.
The main available product, which serves as the main source of sucrose, is ordinary sugar, which is sold in any grocery store. The science of chemistry denotes a sucrose molecule, which is an isomer, as follows - C 12 H 22 O 11.
Interaction of sucrose with water (hydrolysis)
C 12 H 22 O 11 + H 2 O → C 6 H 12 O 6 + C 6 H 12 O 6
Sucrose is considered the most important of the disaccharides. From the equation, it can be seen that the hydrolysis of sucrose leads to the formation of fructose and glucose.
The molecular formulas of these elements are the same, but the structural formulas are completely different.
Fructose - CH 2 - CH - CH - CH -C - CH 2.
Glucose - CH 2 (OH) - (CHOH) 4 - SON.
Sucrose and its physical properties
Sucrose is a sweet colorless crystals, highly soluble in water. The melting point of sucrose is 160 °C. When the molten sucrose solidifies, an amorphous transparent mass is formed - caramel.
Properties of sucrose:
- It is the most important disaccharide.
- Does not apply to aldehydes.
- When heated with Ag 2 O (ammonia solution) does not give the effect of "silver mirror".
- When heated with Cu(OH) 2 (copper hydroxide), red copper oxide does not appear.
- If you boil a solution of sucrose with a few drops of hydrochloric or sulfuric acid, then neutralize it with any alkali, then heat the resulting solution with Cu (OH) 2, you can observe a red precipitate.
Compound
The composition of sucrose, as you know, includes fructose and glucose, more precisely, their residues. Both of these elements are closely related. Among the isomers having the molecular formula C 12 H 22 O 11, the following should be distinguished:
- milk sugar ();
- malt sugar (maltose).
Foods containing sucrose
- Irga.
- Medlar.
- Grenades.
- Grape.
- Dried figs.
- Raisins (kishmish).
- Persimmon.
- Prunes.
- Pastila apple.
- Sweet straw.
- Dates.
- Gingerbread.
- Marmalade.
- Bee honey.
How sucrose affects the human body
Important! The substance provides the human body with a full supply of energy, which is necessary for the functioning of all organs and systems.
Sucrose stimulates the protective functions of the liver, improves brain activity, protects a person from exposure to toxic substances.
It supports the activity of nerve cells and striated muscles.
For this reason, the element is considered the most important among those found in almost all foods.
If the human body is deficient in sucrose, the following symptoms can be observed:
- prostration;
- lack of energy;
- apathy;
- irritability;
- depression.
Moreover, the state of health can gradually deteriorate, so you need to normalize the amount of sucrose in the body in time.
High levels of sucrose are also very dangerous:
- itching of the genitals;
- candidiasis;
- inflammatory processes in the oral cavity;
- periodontal disease;
- overweight;
- caries.
If the human brain is overloaded with active mental activity or the body has been exposed to toxic substances, the need for sucrose increases dramatically. Conversely, this need is reduced if a person is overweight or suffers from diabetes.
How glucose and fructose affect the human body
As a result of the hydrolysis of sucrose, glucose and fructose are formed. What are the main characteristics of both of these substances, and how do they affect human life?
Fructose is a type of sugar molecule found in high amounts in fresh fruits, giving them their sweetness. In this regard, it can be assumed that fructose is very useful, since it is a natural component. Fructose, which has a low glycemic index, does not increase blood sugar levels.
The product itself is very sweet, but it is included in the composition of fruits known to man only in small quantities. Therefore, only a minimal amount of sugar enters the body, and it is instantly processed.
However, large amounts of fructose should not be introduced into the diet. Its unreasonable use can provoke:
- fatty liver;
- scarring of the liver - cirrhosis;
- obesity;
- heart diseases;
- diabetes;
- gout;
- premature aging of the skin.
The researchers concluded that, unlike glucose, fructose causes signs of aging much faster. Talking about its substitutes in this regard does not make sense at all.
Based on the foregoing, we can conclude that eating fruits in reasonable amounts for the human body is very useful, since they contain a minimum amount of fructose.
Like fructose, glucose is a type of sugar and the most common form of carbohydrate. The product is obtained from starches. Glucose provides the human body, in particular its brain, with a supply of energy for quite a long time, but significantly increases the concentration of sugar in the blood.
Note! With regular consumption of highly processed foods or simple starches (white flour, white rice), blood sugar will rise significantly.
Problems:
- diabetes;
- non-healing wounds and ulcers;
- high levels of lipids in the blood;
- damage to the nervous system;
- kidney failure;
- overweight;
- ischemic heart disease, stroke, heart attack.
sucrose C 12 H 22 O 11, or beet sugar, cane sugar, in everyday life just sugar - a disaccharide from the group of oligosaccharides, consisting of two monosaccharides - α-glucose and β-fructose.
Chemical properties of sucrose
An important chemical property of sucrose is the ability to undergo hydrolysis (when heated in the presence of hydrogen ions).
Since the bond between monosaccharide residues in sucrose is formed by both glycosidic hydroxyls, it does not have restorative properties and does not give a "silver mirror" reaction. Sucrose retains the properties of polyhydric alcohols: it forms water-soluble sugars with metal hydroxides, in particular, with calcium hydroxide. This reaction is used to isolate and purify sucrose in sugar refineries, which we will talk about a little later.
When an aqueous solution of sucrose is heated in the presence of strong acids or under the action of an enzyme invertases going on hydrolysis of this disaccharide to form a mixture of equal amounts of glucose and fructose. This reaction is the reverse of the formation of sucrose from monosaccharides:
The resulting mixture is called invert sugar and is used for the production of caramel, sweetening food products, to prevent the crystallization of sucrose, obtaining artificial honey, and the production of polyhydric alcohols.
Relation to hydrolysis
The hydrolysis of sucrose is easy to follow with a polarimeter, since the sucrose solution has right-hand rotation, and the resulting mixture D- glucose and D- fructose has a left rotation, due to the prevailing value of the left rotation of D-fructose. Consequently, as sucrose is hydrolyzed, the angle of right rotation gradually decreases, passes through zero, and at the end of hydrolysis, a solution containing equal amounts of glucose and fructose acquires a stable left rotation. In this regard, hydrolyzed sucrose (a mixture of glucose and fructose) is called invert sugar, and the hydrolysis process itself is called inversion (from Latin inversia - turning, rearranging).
The structure of maltose and celobiose. Relation to hydrolysis
Maltose and starch. Composition, structure and properties. Relation to hydrolysis
Physical properties
Maltose is easily soluble in water and has a sweet taste. The molecular weight of maltose is 342.32. The melting point of maltose is 108 (anhydrous).
Chemical properties
Maltose is a reducing sugar because it has an unsubstituted hemiacetal hydroxyl group.
By boiling maltose with dilute acid and by the action of an enzyme maltose hydrolyzes (two molecules of glucose C 6 H 12 O 6 are formed).
Starch (C 6 H 10 O 5) n polysaccharides of amylose and amylopectin, the monomer of which is alpha-glucose. Starch, synthesized by different plants in chloroplasts, under the action of light during photosynthesis, differs somewhat in the structure of grains, the degree of polymerization of molecules, the structure of polymer chains, and physicochemical properties.
It is useful to know the chemical formulas of substances common in everyday life not only as part of a school chemistry course, but simply for general erudition. Almost everyone knows the formula for water or table salt, but few can immediately get to the point about alcohol, sugar or vinegar. Let's go from simple to complex.
What is the formula for water?
This liquid, thanks to which amazing wildlife appeared on planet Earth, is known and drunk by everyone. Moreover, it makes up about 70% of our body. Water is the simplest combination of an oxygen atom with two hydrogen atoms.
Chemical formula of water: H 2 O
What is the formula for table salt?
Table salt is not only an indispensable culinary dish, but also one of the main components of sea salt, the reserves of which in the World Ocean amount to millions of tons. The formula for common salt is simple and easy to remember: 1 sodium atom and 1 chlorine atom.
Chemical formula of table salt: NaCl
What is the formula for sugar?
Sugar is a white crystalline powder, without which no sweet tooth in the world can live a day. Sugar is a complex organic compound whose formula is hard to remember: 12 carbon atoms, 22 hydrogen atoms and 11 oxygen atoms form a sweet and complex structure.
Chemical formula of sugar: C 12 H 22 O 11
What is the formula for vinegar?
Vinegar is a solution of acetic acid, which is used for food, as well as for cleaning metals from plaque. The acetic acid molecule has a complex structure consisting of two carbon atoms, to one of which three hydrogen atoms are attached, and to the other two oxygen atoms, one of which has taken another hydrogen.
Chemical formula of acetic acid: CH 3 COOH
What is the formula for alcohol?
Let's start with the fact that alcohols are different. The alcohol that is used to make wines, vodkas and cognacs is scientifically called ethanol. In addition to ethanol, there are still a bunch of alcohols that are used in medicine, automotive and aviation.
Chemical formula of ethanol: C 2 H 5 OH
What is the formula for baking soda?
Baking soda is scientifically called sodium bicarbonate. From this name, any novice chemist will understand that the soda molecule contains sodium, carbon, oxygen and hydrogen.
Chemical formula of baking soda: NaHCO 3
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