1.1. Sucrose
For normal nutrition of an adult man who is not burdened with much physical work, it is necessary to take a nutritious amount of food per day. energy value(calorie content) which is approximately 3000 kcal. This corresponds to the intake of the following amount of essential nutrients (in pure form): 100 g proteins(calorie content 1 g - 4.8 kcal, or 20.1 kJ), 100 g fat(calorie content 9.3 kcal/g) and 400 g carbohydrates(calorie content 4 kcal/g).
In terms of calorie content, carbohydrates are inferior to proteins and fats, but in a person’s daily diet the total calorie content of carbohydrates is more than half, and in terms of food volume - about two-thirds. Carbohydrates are the main source of energy for the human body.
The main carbohydrate in human nutrition is the water-insoluble polysaccharide starch (in bread grains, potatoes, etc.) - for absorption in the body, it must first of all be decomposed into monosaccharides and transferred into solution (this is produced by enzymes of saliva and gastric juice), to that it takes time. A soluble carbohydrate is a disaccharide. sucrose, or ordinary sugar, decomposes into monosaccharides (glucose and fructose) and is absorbed much faster than starch, which is why people so willingly replace part of the starch in their diet with sugar, which also has a sweet taste. To quickly restore expended energy (during hiking, sports, heavy physical work, for sick and convalescent people), sugar is used as nutrient It is especially valuable for its speed and ease of absorption.
Thanks to valuable nutritional, taste and physical properties sucrose (sugar) became an essential food product.
The rapid digestibility of sucrose, however, does not allow it to be used as the only dietary carbohydrate. Relatively slowly digested starch evenly supplies the blood with glucose. Consumption of sucrose in significant doses overloads the blood with glucose, which in this case begins to be processed into fats, i.e. obesity begins. Therefore, it is determined that only up to 20% of the required amount of carbohydrates can be consumed in the form of sugar. Thus, it is permissible to consume approximately 80 g of sugar per day in all its forms (in kind, in confectionery, in drinks, etc.), which is about 30 kg of sugar per year.
The regular sugar we buy in the store is more than 99.7% sucrose.
SUGAROSE belongs to a large class of naturally occurring organic substances called carbohydrates (compounds of carbon atoms and water molecules) with the general formula: C m (H 2 O) n
This class includes more or less sweet-tasting sugars, both monosaccharides (for example, glucose and fructose) and oligosaccharides (for example, sucrose and raffinose), as well as polysaccharides (for example, cellulose and starch).
Sucrose (cane, beet sugar) is a disaccharide with the general empirical formula C 12 H 22 O 11, consisting of two equal parts of monosaccharides: d-glucose and d-fructose. These monosaccharides are connected to each other by glucoside groups: glucose in a -configurations and fructose in b -configurations. In the sucrose molecule, glucose is in the pyranose form (pyran ring), and fructose is in the furanoside form (furan ring). Thus, sucrose is a -d-glucopyranosyl- b -d-fructofuranoside.
Molecular mass sucrose - 342.296. The sucrose molecule contains 42.11% carbon, 6.43% hydrogen and 51.46% oxygen.
Sucrose is crystalline substance, the molecular structure of which has a special lattice that is natural for it.
Normal, grown in pure solution The sucrose crystal has a complex multifaceted (15 or more faces) shape.
There are 15 known types of sucrose crystals; twin crystals are often observed; the shape of the crystals depends on the conditions of the crystallization process, impurities in the original solution and the degree of supersaturation of this solution with sucrose.
The density of sucrose crystals without inclusions at 20 o C is 1.5915 g/cm 3 , specific volume is 0.628 cm 3 /g.
Crystals 1.5-2.5 mm in size belong to the coarse fraction, 0.5-1.5 mm in size - medium, and up to 0.5 mm in size - small.
1 g contains approximately the following amount of sucrose crystals:
Pure sucrose crystals are transparent and colorless. When crushed, sucrose crystals produce very bright flashes of crystalloluminescence. The sucrose crystal is an insulator. The volumetric thermal expansion of sucrose is 0.00011% per 1°C.
Pure sucrose solutions are not electrically conductive and chemically neutral, i.e. their pH=7.
In aqueous solutions, sucrose under the influence of acids, adding water, is split (inversion process) into its constituent parts - glucose and fructose.
Under the influence of certain enzymes, yeast, mold and bacteria, sucrose is also broken down into glucose and fructose.
Solubility of sucrose in clean water significant and increases rapidly with increasing temperature. Sucrose is practically insoluble in ethyl and methyl alcohols.
Sucrose melts at a temperature of 186-188°C, the so-called. “caramelization” of sucrose, or the formation of complex, brown-colored, bitter-tasting substances.
Chemically pure sucrose for scientific research prepared by dissolving the best refined commercial sugar in distilled water, followed by precipitation with anhydrous ethyl alcohol, and this process is repeated several times.
Habitual sweet sugar, used in everyday life, is called sucrose. It is an oligosaccharide belonging to the group of disaccharides. The formula of sucrose is C 12 H 22 O 11.
The molecule contains residues of two cyclic monosaccharides- α-glucose and β-fructose. The structural formula of the substance consists of the cyclic formulas of fructose and glucose connected by an oxygen atom. The structural units are linked together by a glycosidic bond formed between two hydroxyls.
Rice. 1. Structural formula.
Sucrose molecules form a molecular crystal lattice.
Sucrose is the most common carbohydrate in nature. The compound is found in fruits, berries, and plant leaves. A large amount of the finished substance is found in beets and sugar cane. Therefore, sucrose is not synthesized, but isolated through physical action, digestion and purification.
Rice. 2. Sugar cane.
Beets or sugar cane are finely grated and placed in large cauldrons with hot water. The sucrose is washed out to form a sugar solution. It contains various impurities - coloring pigments, proteins, acids. To separate sucrose, calcium hydroxide Ca(OH) 2 is added to the solution. As a result, a precipitate and calcium saccharate C 12 H 22 O 11 CaO 2H 2 O are formed, through which carbon dioxide is passed ( carbon dioxide). Calcium carbonate precipitates, and the remaining solution is evaporated until sugar crystals form.
Basic physical characteristics substances:
Rice. 3. Sugar crystals.
If the molten substance is continued to be heated, the sucrose will begin to decompose and change color. When molten sucrose hardens, caramel is formed - an amorphous transparent substance. Under normal conditions, 211.5 g of sugar can be dissolved in 100 ml of water, 176 g at 0°C, and 487 g at 100°C. Under normal conditions, only 0.9 g of sugar can be dissolved in 100 ml of ethanol.
Once in the intestines of animals and humans, sucrose quickly breaks down into monosaccharides under the action of enzymes.
Unlike glucose, sucrose does not exhibit the properties of an aldehyde due to the absence of the aldehyde group -CHO. Therefore, the qualitative reaction of the “silver mirror” (interaction with an ammonia solution of Ag 2 O) does not occur. Oxidation with copper(II) hydroxide produces not red copper(I) oxide, but a bright blue solution.
Basic Chemical properties are described in the table.
Sucrose is not capable of oxidation (it is not a reducing agent in reactions) and is called non-reducing sugar.
Sugar in its pure form is used in Food Industry for the manufacture of artificial honey, sweets, confectionery, alcohol. Sucrose is used to produce various substances: citric acid, glycerin, butanol.
In medicine, sucrose is used to make mixtures and powders to mask the unpleasant taste.
Sucrose or sugar is a disaccharide consisting of glucose and fructose residues. It has a sweet taste and easily dissolves in water. The substance is isolated from beets and sugar cane. Sucrose is less active than glucose. It undergoes hydrolysis, reacts with copper (II) hydroxide, forming copper saccharate, and does not oxidize. Sugar is used in food chemical industry, medicine.
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In sucrose solution, ring opening does not occur, so it does not have the properties of aldehydes.
1) Hydrolysis (in acidic environment):
C 12 H 22 O 11 + H 2 O → C 6 H 12 O 6 + C 6 H 12 O 6.
sucrose glucose fructose
2) Being a polyhydric alcohol, sucrose gives a blue color to the solution when reacting with Cu(OH) 2.
3) Interaction with calcium hydroxide to form calcium sucrose.
4) Sucrose does not react with an ammonia solution of silver oxide, so it is called a non-reducing disaccharide.
Polysaccharides.
Polysaccharides– high molecular weight non-sugar-like carbohydrates containing from ten to hundreds of thousands of monosaccharide residues (usually hexoses) linked by glycosidic bonds.
The most important polysaccharides are starch and cellulose (fiber). They are built from glucose residues. The general formula of these polysaccharides is (C 6 H 10 O 5) n. In the formation of polysaccharide molecules, glycosidic (at the C 1 atom) and alcoholic (at the C 4 atom) hydroxyls usually take part, i.e. a (1–4)-glycosidic bond is formed.
From point of view general principles structurally, polysaccharides can be divided into two groups, namely: homopolysaccharides, consisting of monosaccharide units of only one type, and heteropolysaccharides, which are characterized by the presence of two or more types of monomer units.
From point of view functional purpose Polysaccharides can also be divided into two groups: structural and reserve polysaccharides. Important structural polysaccharides are cellulose and chitin (in plants and animals, as well as in fungi, respectively), and the main reserve polysaccharides are glycogen and starch (in animals, as well as in fungi, and plants, respectively). Only homopolysaccharides will be considered here.
Cellulose (fiber)− the most widespread structural polysaccharide of the plant world.
home component plant cell, synthesized in plants (in wood up to 60% cellulose). Cellulose has great mechanical strength and acts as a support material for plants. Wood contains 50-70% cellulose, cotton is almost pure cellulose.
Pure cellulose is a white fibrous substance, tasteless and odorless, insoluble in water and other solvents.
Cellulose molecules have a linear structure and high molecular weight; they consist only of unbranched molecules in the form of threads, because the shape of β-glucose residues excludes helicalization. Cellulose consists of thread-like molecules, which are assembled into bundles by hydrogen bonds of hydroxyl groups within the chain, as well as between adjacent chains. It is this packaging of chains that ensures high mechanical strength, fibrousness, insolubility in water and chemical inertness, which makes cellulose ideal material to build cell walls.
Cellulose consists of α,D-glucopyranose residues in their β-pyranose form, i.e., in the cellulose molecule, β-glucopyranose monomer units are linearly connected to each other by β-1,4-glucosidic bonds:
With partial hydrolysis of cellulose, the disaccharide cellobiose is formed, and with complete hydrolysis, D-glucose is formed. The molecular weight of cellulose is 1,000,000−2,000,000. Fiber is not digested by enzymes of the gastrointestinal tract, since the set of these enzymes of the human gastrointestinal tract does not contain β-glucosidase. However, it is known that the presence of optimal amounts of fiber in food promotes the formation of feces. With the complete exclusion of fiber from food, the formation of feces is disrupted.
Starch- a polymer of the same composition as cellulose, but with an elementary unit representing an α-glucose residue:
Starch molecules are coiled, most of the molecules are branched. The molecular weight of starch is less than the molecular weight of cellulose.
Starch is amorphous substance, white powder consisting of small grains, insoluble in cold water, but partially soluble in hot.
Starch is a mixture of two homopolysaccharides: linear - amylose and branched - amylopectin, general formula of which (C 6 H 10 O 5) n.
When processing starch warm water it is possible to isolate two fractions: a fraction soluble in warm water and consisting of amylose polysaccharide, and a fraction that only swells in warm water to form a paste and consists of amylopectin polysaccharide.
Amylose has a linear structure, α, D-glucopyranose residues are linked by (1–4)-glycosidic bonds. The unit cell of amylose (and starch in general) is represented as follows:
The amylopectin molecule is built in a similar way, but has branches in the chain, which creates a spatial structure. At branching points, monosaccharide residues are linked by (1–6)-glycosidic bonds. Between the branch points there are usually 20-25 glucose residues.
(amylopectin)
As a rule, the amylose content in starch is 10-30%, amylopectin - 70-90%. Starch polysaccharides are built from glucose residues connected in amylose and in the linear chains of amylopectin by α-1,4-glucosidic bonds, and at the branch points of amylopectin by interchain α-1,6-glucosidic bonds.
An amylose molecule contains, on average, about 1000 glucose residues; individual linear sections of the amylopectin molecule consist of 20-30 such units.
In water, amylose does not give a true solution. The amylose chain in water forms hydrated micelles. In solution, when iodine is added, amylose becomes colored Blue colour. Amylopectin also produces micellar solutions, but the shape of the micelles is slightly different. The polysaccharide amylopectin is stained red-violet with iodine.
Starch has a molecular weight of 10 6 -10 7. With partial acid hydrolysis of starch, polysaccharides of a lower degree of polymerization are formed - dextrins, with complete hydrolysis - glucose. Starch is the most important dietary carbohydrate for humans. Starch is formed in plants during photosynthesis and is deposited as a “reserve” carbohydrate in roots, tubers and seeds. For example, grains of rice, wheat, rye and other cereals contain 60-80% starch, potato tubers - 15-20%. A related role in the animal world is played by the polysaccharide glycogen, which is “stored” mainly in the liver.
Glycogen− the main reserve polysaccharide of higher animals and humans, built from α-D-glucose residues. The empirical formula of glycogen, like starch, is (C 6 H 10 O 5) n. Glycogen is found in almost all organs and tissues of animals and humans; greatest number it is found in the liver and muscles. The molecular weight of glycogen is 10 7 -10 9 and higher. Its molecule is built from branching polyglucosidic chains, in which glucose residues are connected by α-1,4-glucosidic bonds. There are α-1,6-glucosidic linkages at the branch points. Glycogen is close in structure to amylopectin.
In the glycogen molecule, there are internal branches - sections of polyglucoside chains between branch points, and external branches - sections from the peripheral branch point to the non-reducing end of the chain. During hydrolysis, glycogen, like starch, is broken down to first form dextrins, then maltose and, finally, glucose.
Chitin− structural polysaccharide of lower plants, especially fungi, as well as invertebrate animals (mainly arthropods). Chitin consists of 2-acetamido-2-deoxy-D-glucose residues linked by β-1,4-glucosidic bonds.
Scientists have proven that sucrose is integral part all plants. Substance in large quantities found 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 (part of the class of oligosaccharides). Under the action of its enzyme or acid, sucrose breaks down into fructose (fruit sugar) and glucose, which makes up most polysaccharides.
In other words, sucrose molecules consist of D-glucose and D-fructose residues.
The main available product that serves as the main source of sucrose is regular sugar, which is sold in any grocery store. The science of chemistry designates the sucrose molecule, which is an isomer, as follows - C 12 H 22 O 11.
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 you can see 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 is a sweet, colorless crystal that is highly soluble in water. The melting point of sucrose is 160 °C. When molten sucrose hardens, an amorphous transparent mass is formed - caramel.
Properties of sucrose:
As is known, sucrose contains fructose and glucose, or rather, their residues. Both of these elements are closely connected to each other. Among the isomers with the molecular formula C 12 H 22 O 11, the following should be distinguished:
Important! The substance provides human body 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, and protects a person from the effects of 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 food products.
If the human body is deficient in sucrose, the following symptoms can be observed:
Moreover, your health may gradually deteriorate, so you need to normalize the amount of sucrose in the body in time.
High levels of sucrose are also very dangerous:
If a person’s brain is overloaded with active mental activity or the body is exposed to toxic substances, the need for sucrose increases sharply. Conversely, this need decreases if a person is overweight or has diabetes.
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 and is found in large quantities 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 the composition known to man It is included in fruits only in small quantities. Therefore, only a minimal amount of sugar enters the body, and it is instantly processed.
However, you should not introduce large amounts of fructose into your diet. Its unreasonable use can provoke:
The researchers concluded that, unlike glucose, fructose causes signs of aging much more quickly. It makes no sense at all to talk about its substitutes in this regard.
Based on the foregoing, we can conclude that eating fruits in reasonable quantities is very beneficial for the human body, since they contain a minimal 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 the brain, with a supply of energy for quite a long time, but significantly increases the concentration of sugar in the blood.
Note! If you regularly eat highly processed foods or simple starches (white flour, white rice), your blood sugar will rise significantly.
Problems:
One of the most famous carbohydrates is sucrose. It is used in cooking food products, it is also found in the fruits of many plants.
This carbohydrate is one of the main sources of energy in the body, but its excess can lead to dangerous pathologies. Therefore, it is worth familiarizing yourself with its properties and features in more detail.
Sucrose is organic compound formed from glucose and fructose residues. It is a disaccharide. Its formula is C12H22O11. This substance has a crystalline form. It has no color. The taste of the substance is sweet.
It is distinguished by excellent solubility in water. This compound can also be dissolved in methanol and ethanol. To melt this carbohydrate, a temperature of 160 degrees is required, as a result of this process caramel is formed.
The formation of sucrose requires the detachment of water molecules from simple saccharides. It does not exhibit aldehyde and ketone properties. When reacting with copper hydroxide, it forms saccharates. The main isomers are lactose and maltose.
Analyzing what this substance consists of, we can name the first thing that distinguishes sucrose from glucose - sucrose has a more complex structure, and glucose is one of its elements.
In addition, the following differences can be mentioned:
These properties are the main differences between two substances that have quite a lot of similarities. How to distinguish between glucose and sucrose in a simpler way? It's worth comparing their colors. Sucrose is a colorless compound with a slight sheen. Glucose is also a crystalline substance, but its color is white.
The human body is incapable of direct absorption of sucrose; this requires hydrolysis. The compound is digested in the small intestine, where fructose and glucose are released. It is they that are subsequently broken down, turning into the energy necessary for life. We can say that the main function of sugar is energy.
Thanks to this substance, the following processes occur in the body:
However, despite the presence useful properties, this carbohydrate is considered “empty”, so its excessive consumption can cause problems in the body.
This means that the amount per day should not be too large. Optimally, it should be no more than 10th of the calories consumed. Moreover, this should include not only pure sucrose, but also that which is included in other food products.
You should not completely exclude this compound from your diet, since such actions are also fraught with consequences.
Its deficiency is indicated by such unpleasant phenomena as:
Sometimes the body may experience an increased need for the product. This happens during active mental activity, since the passage of nerve impulses requires energy. This need also arises if the body is exposed to a toxic load (sucrose in this case becomes a barrier to protect liver cells).
Abuse of this compound can be dangerous. This is due to the formation of free radicals, which occurs during hydrolysis. Because of them, the immune system is weakened, which leads to increased vulnerability of the body.
In this regard, it is necessary to limit the consumption of this substance, preventing its excessive accumulation.
To control the amount of sucrose consumed, you need to know where this compound is found.
It is found in many foods and is also widely distributed in nature.
It is very important to consider which plants contain the component - this will limit its use to the required level.
Natural source large quantity This carbohydrate in hot countries is sugar cane, and in countries with temperate climates it is sugar beets, Canadian maple and birch.
Fruits and berries also contain a lot of substances:
In addition, the compound is contained in many sweets (ice cream, candies, baked goods) and certain types of dried fruits.
The production of sucrose involves its industrial extraction from sugar-containing crops. In order for a product to comply with GOST standards, technology must be followed.
It consists of performing the following actions:
After this, the substance is crystallized and packaged for sale.
Video about sugar production:
Since sucrose has many valuable properties, it is widely used.
The main areas of its use are:
The product is also used in cosmetology, agriculture, in the production of household chemicals.
This aspect is one of the most important. Many people are trying to understand whether it is worth using a substance and products with its addition in Everyday life. Information about his availability harmful properties spread widely. However, we must not forget about the positive impact of the product.
The most important effect of the compound is to supply the body with energy. Thanks to it, all organs and systems can function properly, and a person does not experience fatigue. Under the influence of sucrose, neural activity is activated and the ability to resist toxic effects increases. Due to this substance, the activity of nerves and muscles is carried out.
With a lack of this product, a person’s well-being rapidly deteriorates, his performance and mood decrease, and signs of overwork appear.
We must not forget about the possibility negative impact Sahara. With him increased content a person can develop numerous pathologies.
Among the most likely are:
In this regard, it is necessary to monitor the amount of sucrose consumed. In this case, you need to take into account the needs of the body. In some circumstances, the need for this substance increases, and this needs to be paid attention to.
Video about the benefits and harms of sugar:
You should also be aware of the limitations. Intolerance to this compound - a rare event. But if it is detected, this means complete exclusion of this product from the diet.
Another limitation is diabetes. Is it possible to consume sucrose if you have diabetes? It’s better to ask your doctor. This is influenced different features: clinical picture, symptoms, individual properties of the body, patient’s age, etc.
A specialist can completely prohibit the consumption of sugar, since it increases the concentration of glucose, causing deterioration. The exception is cases of hypoglycemia, to neutralize which sucrose or products containing it are often used.
In other situations, it is assumed that this compound is replaced with sweeteners that do not increase blood glucose levels. Sometimes the ban on the use of this substance is not strict, and the diabetic is allowed to use the desired product from time to time.
