Carbohydrates are organic compounds composed primarily of three chemical elements - carbon, hydrogen and oxygen, although a number of carbohydrates also contain nitrogen or sulfur. The general formula of carbohydrates is C m (H 2 0) n. They are divided into simple and complex carbohydrates.

Simple carbohydrates (monosaccharides) contain a single sugar molecule that cannot be broken down into simpler ones. These are crystalline substances, sweet in taste and highly soluble in water. Monosaccharides take an active part in cell metabolism and are part of complex carbohydrates - oligosaccharides and polysaccharides.

Monosaccharides are classified according to the number of carbon atoms (C 3 -C 9), for example, pentoses(C 5) and hexoses(C 6). Pentoses include ribose and deoxyribose. Ribose is part of RNA and ATP. Deoxyribose is a component of DNA. Hexoses (C 6 H 12 0 6) are glucose, fructose, galactose, etc.

Glucose(grape sugar) (Fig. 2.7) is found in all organisms, including human blood, since it is an energy reserve. It is part of many complex sugars: sucrose, lactose, maltose, starch, cellulose, etc.

Fructose(fruit sugar) is found in highest concentrations in fruits, honey, and sugar beet roots. It not only takes an active part in metabolic processes, but is also part of sucrose and some polysaccharides, such as insulin.

Most monosaccharides are capable of giving a “silver mirror” reaction and reducing copper when adding feling liquid (a mixture of solutions of copper (II) sulfate and potassium sodium tartrate) and boiling.

TO oligosaccharides include carbohydrates formed by several monosaccharide residues. They are generally also highly soluble in water and sweet in taste. Depending on the number of these residues, disaccharides are distinguished (two residues),

Rice. 2.7. Structure of the glucose molecule

trisaccharides (three), etc. Disaccharides include sucrose, lactose, maltose, etc.

Sucrose(beet or cane sugar) consists of residues of glucose and fructose (Fig. 2.8), it is found in the storage organs of some plants. There is especially a lot of sucrose in the root crops of sugar beets and sugar cane, from where they are obtained industrially. It serves as the standard for the sweetness of carbohydrates.

Lactose, or milk sugar, formed by glucose and galactose residues, found in mother's and cow's milk.

Maltose(malt sugar) consists of two glucose units. It is formed during the breakdown of polysaccharides in plant seeds and in the human digestive system, and is used in the production of beer.

Polysaccharides are biopolymers whose monomers are mono- or disaccharide residues. Most polysaccharides are insoluble in water and have an unsweetened taste. These include starch, glycogen, cellulose and chitin.

Starch- This is a white powdery substance that is not wetted by water, but when brewed with hot water it forms a suspension - a paste. In reality, starch consists of two polymers - the less branched amylose and the more branched amylopectin (Fig. 2.9). The monomer of both amylose and amylopectin is glucose. Starch is the main storage substance of plants, which accumulates in huge quantities in seeds, fruits, tubers, rhizomes and other storage organs of plants. A qualitative reaction to starch is a reaction with iodine, in which the starch turns blue-violet.

Glycogen(animal starch) is a reserve polysaccharide of animals and fungi, which in humans accumulates in the largest quantities in the muscles and liver. It is also insoluble in water and does not taste sweet. The monomer of glycogen is glucose. Compared to starch molecules, glycogen molecules are even more branched.

Cellulose, or fiber,- the main supporting polysaccharide of plants. The monomer of cellulose is glucose (Fig. 2.10). Unbranched cellulose molecules form bundles that make up cell walls plants and some mushrooms. Cellulose is the basis of wood, it is used in construction, in the production of textiles, paper, alcohol and many organic substances. Cellulose is chemically inert and does not dissolve in either acids or alkalis. It is also not broken down by enzymes in the human digestive system, but its digestion is facilitated by bacteria in the large intestine. In addition, fiber stimulates contractions of the walls of the gastrointestinal tract, helping to improve its functioning.

Chitin is a polysaccharide whose monomer is a nitrogen-containing monosaccharide. It is part of the cell walls of fungi and arthropod shells. The human digestive system also lacks the enzyme for digesting chitin; only some bacteria have it.

Functions of carbohydrates. Carbohydrates perform plastic (construction), energy, storage and support functions in the cell. They form the cell walls of plants and fungi. The energy value of the breakdown of 1 g of carbohydrates is 17.2 kJ. Glucose, fructose, sucrose, starch and glycogen are storage substances. Carbohydrates can also be part of complex lipids and proteins, forming glycolipids and glycoproteins, particularly in cell membranes. No less important is the role of carbohydrates in intercellular recognition and perception of signals from the external environment, since they function as receptors as part of glycoproteins.

Lipids is a chemically heterogeneous group of low molecular weight substances with hydrophobic properties. These substances are insoluble in water and form emulsions in it, but are highly soluble in organic solvents. Lipids are oily to the touch, many of them leave characteristic non-drying marks on paper. Together with proteins and carbohydrates, they are one of the main components of cells. The content of lipids in different cells is not the same, there is especially a lot of it in the seeds and fruits of some plants, in the liver, heart, and blood.

Depending on the structure of the molecule, lipids are divided into simple And complex. TO simple Lipids include neutral lipids (fats), waxes, sterols and steroids. Complex Lipids also contain another, non-lipid component. The most important of them are phospholipids, glycolipids, etc.

Fats are derivatives of the trihydric alcohol glycerol and higher fatty acids (Fig. 2.11). Most fatty acids contain 14-22 carbon atoms. Among them there are both saturated and unsaturated, that is, containing double bonds. The most common saturated fatty acids are palmitic and stearic, and the most common unsaturated fatty acids are oleic. Some unsaturated fatty acids are not synthesized in the human body or are synthesized in insufficient quantities, and are therefore indispensable. Glycerol residues form hydrophilic “heads”, and fatty acid residues form “tails”.

Fats primarily perform a storage function in cells and serve as a source of energy. They are rich in subcutaneous fatty tissue, which performs shock-absorbing and thermal insulation functions, and in aquatic animals also increases buoyancy. Plant fats mostly contain unsaturated fatty acids, as a result of which they are liquid and are called oils. Oils are contained in the seeds of many plants, such as sunflower, soybeans, rapeseed, etc.

Waxes- These are complex mixtures of fatty acids and fatty alcohols. In plants, they form a film on the surface of the leaf, which protects against evaporation, penetration of pathogens, etc. In a number of animals, they cover the body or serve to build honeycombs.

TO sterols This includes a lipid such as cholesterol, an essential component of cell membranes, and steroids - the sex hormones estradiol, testosterone, etc.

Phospholipids, in addition to glycerol and fatty acid residues, they contain an orthophosphoric acid residue. They are part of cell membranes and provide their barrier properties.

Glycolipids are also components of membranes, but their content there is small. The non-lipid part of glycolipids are carbohydrates.

Functions of lipids. Lipids perform plastic (construction), energy, storage, protective and regulatory functions in the cell; in addition, they are solvents for a number of vitamins. It is an essential component of cell membranes. When 1 g of lipids is broken down, 38.9 kJ of energy is released. They are stored in reserve various organs plants and animals. In addition, subcutaneous fatty tissue protects internal organs from hypothermia or overheating, as well as shock. The regulatory function of lipids is due to the fact that some of them are hormones.

Carbohydrates are organic compounds that consist of one or more simple sugar molecules. They can be classified into three groups - monosaccharides, oligosaccharides and polysaccharides. They all differ in the composition of sugar molecules and have different effects on the body. What are insoluble carbohydrates for? Conventionally, these organic compounds can be divided into water-insoluble and soluble carbohydrates. Soluble carbohydrates include monosaccharides. But only if they have an alpha configuration. These elements are easily digested in the digestive tract. Insoluble carbohydrates are referred to as fiber, which includes cellulose, hemicellulose, pectin, gums, vegetable glue and lignin. All these additives have different chemical properties and are used to prevent diseases in animals.

Insoluble carbohydrates include monosaccharides that have a beta configuration, since they are much more resistant to digestive enzymes. Volatile fatty acids (VFA) are one of the most important sources of energy for the body. But it should be noted that only for herbivores, since meat eaters have limited digestive processes, and these acids do not represent for them energy value. Feeds with such additives are mainly given to those animals that need to lose excess weight. If an animal's diet is not dominated by carbohydrates, it does not significantly affect its body, since it can use body proteins to create glucose.

Which carbohydrates are insoluble in water? These include starch, cellulose, chitin and glycogen. All of them perform the function of structuring, protecting and storing energy in the body. Why do we need carbohydrates? Carbohydrates are an integral part of the human body that allows it to function. Thanks to them, a living organism is filled with energy for further life activity. It is thanks to these organic compounds that glucose levels do not affect the release of insulin into the blood, and this in turn does not lead to more serious consequences.

Basically, all consumed carbohydrates dissolve in water and enter the human body with food. However, it is necessary to remember that it is necessary to regulate the carbohydrates consumed, since their deficiency or excess can lead to undesirable consequences. An excess of these substances can lead to a variety of diseases, ranging from cardiovascular to diabetes mellitus. A deficiency, on the contrary, provokes disturbances in fat metabolism, low sugar levels and many other diseases. phrase 1: carbohydrates are insoluble in water phrase 2: which carbohydrates are insoluble in water phrase 3: carbohydrates are soluble in water

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Water-soluble carbohydrates. - MegaLectures

Functions soluble carbohydrates: transport, protective, signaling, energy.

Monosaccharides: glucose is the main source of energy for cellular respiration. Fructose is a component of flower nectar and fruit juices. Ribose and deoxyribose are structural elements of nucleotides, which are monomers of RNA and DNA.

Disaccharides: sucrose (glucose + fructose) is the main product of photosynthesis transported in plants. Lactose (glucose + galactose) is a component of mammalian milk. Maltose (glucose + glucose) is a source of energy in germinating seeds.

Polymeric carbohydrates:

starch, glycogen, cellulose, chitin. They are not soluble in water.

Functions of polymer carbohydrates: structural, storage, energy, protective.

Starch consists of branched spiral molecules that form storage substances in plant tissues.

Cellulose is a polymer formed by glucose residues consisting of several straight parallel chains connected by hydrogen bonds. This structure prevents the penetration of water and ensures the stability of the cellulose membranes of plant cells.

Chitin consists of amino derivatives of glucose. The main structural element of the integument of arthropods and the cell walls of fungi.

Glycogen is a storage substance in an animal cell. Glycogen is even more branched than starch and is highly soluble in water.

Lipids are esters of fatty acids and glycerol. Insoluble in water, but soluble in non-polar solvents. Present in all cells. Lipids are made up of hydrogen, oxygen and carbon atoms. Types of lipids: fats, waxes, phospholipids.

Functions of lipids:

Storage - fats are stored in the tissues of vertebrate animals.

Energy – half of the energy consumed by the cells of vertebrates at rest is formed as a result of fat oxidation. Fats are also used as a source of water. The energy effect from the breakdown of 1 g of fat is 39 kJ, which is twice as much as the energy effect from the breakdown of 1 g of glucose or protein.

Protective – the subcutaneous fat layer protects the body from mechanical damage.

Structural - phospholipids are part of cell membranes.

Thermal insulation – subcutaneous fat helps retain heat.

Electrical insulating - myelin, secreted by Schwann cells (form the sheaths of nerve fibers), insulates some neurons, which greatly speeds up the transmission of nerve impulses.

Nutritional – some lipid-like substances help build muscle mass and maintain body tone.

Lubricating – waxes cover the skin, fur, feathers and protect them from water. The leaves of many plants are covered with a waxy coating; wax is used in the construction of honeycombs.

Hormonal - adrenal hormone - cortisone and sex hormones are of lipid nature.

Proteins, their structure and functions

Proteins are biological heteropolymers whose monomers are amino acids. Proteins are synthesized in living organisms and perform certain functions in them.

Proteins contain atoms of carbon, oxygen, hydrogen, nitrogen and sometimes sulfur.

The monomers of proteins are amino acids - substances containing unchangeable parts - the amino group Nh3 and the carboxyl group COOH and a changeable part - the radical. It is the radicals that make amino acids different from each other.

Amino acids have the properties of an acid and a base (they are amphoteric), so they can combine with each other. Their number in one molecule can reach several hundred. Alternating different amino acids in different sequences makes it possible to obtain a huge number of proteins with different structures and functions.

Proteins contain 20 types of different amino acids, some of which animals cannot synthesize. They get them from plants that can synthesize all the amino acids. It is to amino acids that proteins are broken down in the digestive tracts of animals. From these amino acids entering the body's cells, its new proteins are built.

Structure of a protein molecule.

The structure of a protein molecule is understood as its amino acid composition, the sequence of monomers and the degree of twisting of the molecule, which must fit in various sections and organelles of the cell, not alone, but together with a huge number of other molecules.

The sequence of amino acids in a protein molecule forms its primary structure. It depends on the sequence of nucleotides in the section of the DNA molecule (gene) encoding the protein. Adjacent amino acids are linked by peptide bonds that occur between the carbon of the carboxyl group of one amino acid and the nitrogen of the amino group of another amino acid.

A long protein molecule folds and first takes on the appearance of a spiral. This is how the secondary structure of the protein molecule arises. Between CO and NH - groups of amino acid residues, adjacent turns of the helix, hydrogen bonds arise that hold the chain together.

A protein molecule of complex configuration in the form of a globule (ball) acquires a tertiary structure. The strength of this structure is provided by hydrophobic, hydrogen, ionic and disulfide S-S bonds.

Some proteins have a quaternary structure, formed by several polypeptide chains (tertiary structures). The quaternary structure is also held together by weak non-covalent bonds - ionic, hydrogen, hydrophobic. However, the strength of these bonds is low and the structure can be easily damaged. When heated or treated with certain chemicals, the protein becomes denatured and loses its biological activity. Disruption of quaternary, tertiary and secondary structures is reversible. The destruction of the primary structure is irreversible.

In any cell there are hundreds of protein molecules that perform various functions. In addition, proteins have species specificity. This means that each species of organism has proteins not found in other species. This creates serious difficulties when transplanting organs and tissues from one person to another, when grafting one type of plant onto another, etc.

Functions of proteins.

Catalytic (enzymatic) - proteins accelerate all biochemical processes occurring in the cell: the breakdown of nutrients in the digestive tract, participate in matrix synthesis reactions. Each enzyme speeds up one and only one reaction (both forward and reverse). Speed enzymatic reactions depends on the temperature of the medium, its pH level, as well as on the concentrations of the reactants and the concentration of the enzyme.

Transport - proteins provide active transport ions across cell membranes, transport of oxygen and carbon dioxide, transport of fatty acids.

Protective – antibodies provide immune protection for the body; fibrinogen and fibrin protect the body from blood loss.

Structural is one of the main functions of proteins. Proteins are part of cell membranes; the protein keratin forms hair and nails; proteins collagen and elastin – cartilage and tendons.

Contractile - provided by contractile proteins - actin and myosin.

Signaling - protein molecules can receive signals and serve as their carriers in the body (hormones). It should be remembered that not all hormones are proteins.

Energy - during prolonged fasting, proteins can be used as additional source energy after carbohydrates and fats are consumed.

Nucleic acids

Nucleic acids were discovered in 1868 by the Swiss scientist F. Miescher. In organisms, there are several types of nucleic acids that are found in various cell organelles - the nucleus, mitochondria, plastids. Nucleic acids include DNA, i-RNA, t-RNA, r-RNA.

Deoxyribonucleic acid (DNA) is a linear polymer in the form of a double helix formed by a pair of antiparallel complementary (corresponding to each other in configuration) chains. The spatial structure of the DNA molecule was modeled by American scientists James Watson and Francis Crick in 1953.

The monomers of DNA are nucleotides. Each DNA nucleotide consists of a purine (A - adenine or G - guanine) or pyrimidine (T - thymine or C - cytosine) nitrogenous base, a five-carbon sugar - deoxyribose and a phosphate group.

The nucleotides in a DNA molecule face each other with nitrogenous bases and are united in pairs in accordance with the rules of complementarity: thymine is located opposite adenine, and cytosine is located opposite guanine. The A – T pair is connected by two hydrogen bonds, and the G – C pair is connected by three. During the replication (doubling) of a DNA molecule, hydrogen bonds are broken and the chains separate, and a new DNA chain is synthesized on each of them. The backbone of DNA chains is formed by sugar phosphate residues.

The sequence of nucleotides in a DNA molecule determines its specificity, as well as the specificity of the body proteins that are encoded by this sequence. These sequences are individual for each type of organism and for individual individuals.

Example: the DNA nucleotide sequence is given: CGA – TTA – CAA.

On messenger RNA (i-RNA), the chain HCU - AAU - GUU will be synthesized, resulting in a chain of amino acids: alanine - asparagine - valine.

When nucleotides in one of the triplets are replaced or rearranged, this triplet will encode a different amino acid, and therefore the protein encoded by this gene will change.

Changes in the composition of nucleotides or their sequence are called mutation.

Ribonucleic acid (RNA) is a linear polymer consisting of a single chain of nucleotides. In RNA, the thymine nucleotide is replaced by uracil (U). Each RNA nucleotide contains a five-carbon sugar - ribose, one of four nitrogenous bases and a phosphoric acid residue.

Types of RNA.

Matrix, or information, RNA. It is synthesized in the nucleus with the participation of the enzyme RNA polymerase. Complementary to the region of DNA where synthesis occurs. Its function is to remove information from DNA and transfer it to the place of protein synthesis - to ribosomes. Makes up 5% of the cell's RNA. Ribosomal RNA is synthesized in the nucleolus and is part of ribosomes. Makes up 85% of the cell's RNA.

Transfer RNA (more than 40 types). Transports amino acids to the site of protein synthesis. It has the shape of a clover leaf and consists of 70-90 nucleotides.

Adenosine triphosphoric acid - ATP. ATP is a nucleotide consisting of a nitrogenous base - adenine, the carbohydrate ribose and three phosphoric acid residues, two of which store a large amount of energy. When one phosphoric acid residue is eliminated, 40 kJ/mol of energy is released. Compare this figure with the figure indicating the amount of energy released by 1 g of glucose or fat. The ability to store such an amount of energy makes ATP its universal source. ATP synthesis occurs mainly in mitochondria.

II. Metabolism: energy and plastic metabolism, their relationship. Enzymes, their chemical nature, role in metabolism. Stages of energy metabolism. Fermentation and respiration. Photosynthesis, its significance, cosmic role. Phases of photosynthesis. Light and dark reactions of photosynthesis, their relationship. Chemosynthesis. The role of chemosynthetic bacteria on Earth

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Test on the topic "Molecular level".

1. the similarity of the elementary composition of cells and bodies of inanimate nature indicates...

A-about the material unity of living and inanimate nature

B-about the dependence of living nature on inanimate

B-changes in living nature under the influence of environmental factors

About their complex chemical composition

2.at what level of organization of life is there a similarity between the organic world and inanimate nature?

A-on fabric

B-on a molecular arm

B-on the cellular

In-at atomic

3. a substance in the cell necessary for all chemical reactions, playing the role of a solvent for most substances, is...

A-polenucleotide

B-polypeptide

G-polysaccharide

4.Water makes up a significant part of the cell, it...

A-regulates vital processes

B-provides the cell with energy

B-gives the cell elasticity

G-promotes cell division

5.What is the average proportion of water in a cell?

6. Substances that are highly soluble in water are called:

A-hydrophilic B-amphiphilic

B-hydrophobic

7.What ions ensure the permeability of cell membranes?

B- Na+ K+ Cl- D-Mg2+

8.Which vital compound contains iron?

A-chlorophyll B-DNA

B-hemoglobin G-RNA

9.what chemical Connection plays a big role in maintaining osmotic pressure in a cage?

A-protein B-NaCl

B-ATP G-Fat

10.What is the name of an organic substance whose molecules contain C, O, H atoms that perform an energy and construction function?

A-nucleic acid B-protein

B-carbohydrate G-ATP

11.What carbohydrates are polymers?

A-monosaccharides

B-disaccharides

B-polysaccharides

12.The group of monosaccharides includes:

A-glucose

B-sucrose

B-cellulose

13.Which carbohydrates are insoluble in water?

A-glucose, fructose B-starch

B-ribose, deoxyribose

14.What polysaccharides are characteristic of a living cell?

A-cellulose B-glycogen, chitin

B-starch

15.Fat molecules are formed:

A-from glycerol, higher carboxylic acids B-from glucose

B-from amino acids, water D-from ethyl alcohol, higher carboxylic acids

16.Fats perform the following functions in the cell:

A-transport B-energy

B-catalytic G-information

17.What compounds do lipids belong to in relation to water?

A-hydrophilic B-hydrophobic

18.What is the importance of fats in animals?

A-membrane structure B-thermoregulation

B-source of energy D-source of water D-all of the above

19.In which solvents are fats soluble?

A-water B-alcohol, ether, gasoline

20.Protein monomers are:

A-nucleotides B-amino acids

B-glucose G-fats

The 21 most important organic substance that is part of the cells of all kingdoms of living nature, which has a primary linear configuration, is:

A-to polysaccharides B-to lipids

B-to ATP G-to polypeptides

22.How many of the known amino acids are involved in protein synthesis?

23.What function do proteins not perform in a cell?

A-informational B-catalytic

B-solvent G-storage

24.Protein molecules that bind and neutralize substances foreign to a given cell perform the function...

A-protective B-energy

B-catalytic G-transport

25.Which part of amino acid molecules distinguishes them from each other?

A-radical B-carboxyl group

B-amino group

26.through what chemical. bonds are amino acids connected to each other in a protein molecule of the primary structure?

A-disulfide B-hydrogen

B-peptide G-ion

27.What is the name of the reversible process of disruption of the structure of one of the most important organic compounds of the cell, occurring under the influence of physical and chemical factors?

A-polymerization of glucose B-denaturation of protein

B-doubling of DNA D-oxidation of fats

28.What compounds are included in ATP?

A-nitrogen base adenine, carbohydrate ribose, 3 molecules of phosphoric acid

B-nitrogen base guanine, sugar fructose, phosphoric acid residue.

B-ribose, glycerol and any amino acid

29.What is the role of ATP molecules in the cell?

A-provide transport function B-transmit hereditary information

B-provide vital processes with energy D-accelerate biochemical reactions

30.monomers of nucleic acids are:

A-amino acids B-fats

B-nucleotides G-glucose

31.What substances are included in the nucleotide?

A-amino acid, glucose B-glycerol, phosphoric acid residue, carbohydrate

B-nitrogen base, sugar pectose, phosphoric acid residue G-carbohydrate pectose, 3 phosphoric acid residues, amino acid.

32.What class of chemical substances does ribose belong to?

A-protein B-carbohydrate

33.Which nucleotide is not included in the DNA molecule?

A-adenylic B-uridylic

B-guanyl G-thymidyl

34.Which nucleic acid has the greatest length and molecular weight?

A-DNA B-RNA

35.RNA is:

A-nucleotide containing two energy-rich bonds

B-molecule having the shape of a double helix, the chains of which are connected by hydrogen bonds

B-single helix

L-long polypeptide chain.

36. Nucleic acids perform the following functions in a cell:

A-catalytic B-construction

B-energy G-information

37What does the information of one DNA triplet correspond to?

A-amino acid B-gene

38individual differences between organisms are due to:

A-DNA, RNA B-fats and carbohydrates

D-nucleic acids and proteins

39.The nucleotide complementary to a guanyl nucleotide is:

A-thymidyl B-cytidyl

B-adenylic G-uridylic

40.The process of doubling DNA molecules is called:

A-replication B-transcription

B-complementarity with G-translation.

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Carbohydrates | Marquis&Ko

Carbohydrates provide the body with energy and play an important role in regulating the gastrointestinal tract. Carbohydrates are divided into two groups depending on their solubility: soluble and insoluble carbohydrates.

Monosaccharides can have alpha or beta configuration. Carbohydrates consisting of α-monosaccharides are easily digested by enzymes digestive tract animals and belong to soluble carbohydrates.

Carbohydrates consisting of β-monosaccharides are resistant to the action of endogenous digestive enzymes and are classified as insoluble carbohydrates. However, in some animal species, microorganisms in the digestive tract produce the enzyme cellulase, which breaks down insoluble carbohydrates into CO2, flammable gases and volatile fatty acids.

Volatile fatty acids (VFAs) are the most important energy source for herbivores. Non-herbivores, such as dogs, have limited microbial digestive processes, so insoluble carbohydrates have no energy value. They reduce the energy nutritional value of the diet.

Therefore, foods containing high levels of insoluble carbohydrates should not be used for dogs with high energy needs (growth, late stages of pregnancy, lactation, stress, work). At the same time, such feeds are successfully used to reduce overweight body and its control in animals prone to obesity.

Alpha bonds in all carbohydrates, with the exception of disaccharides, are broken down by the digestive enzyme amylase. This enzyme is secreted by the pancreas and in some animal species it is not large quantities also secreted by the salivary glands.

Disaccharides (maltose, sucrose, lactose) are broken down into monosaccharides with the help of special enzymes - disaccharidases, such as maltase, isomaltase, sucrase and lactase. These enzymes are contained in the villi of the brush border. epithelial cells intestines. If the brush border structure is damaged or these cells lack these enzymes, then animals are unable to metabolize disaccharides.

With this pathology, disaccharides remain in the intestine and are used by bacteria, stimulating their reproduction and increasing the osmolarity of the intestinal contents, which leads to the release of water into the intestinal lumen and diarrhea (diarrhea). Feeds containing disaccharides, such as milk containing lactose, lead to increased diarrhea if used to feed sick animals.

Soluble carbohydrates are a readily available source of energy and are found in fairly high proportions in many diets, except those that consist almost entirely of meat, fish or animal tissue. When there is an excess content of soluble carbohydrates in the diet, some of the carbohydrates are stored in the body in the form of glycogen or adipose tissue for later use. Therefore, excess carbohydrates in the diet predisposes animals to obesity.

In the absence of carbohydrates in the diet of animals, the concentration of glucose in their blood does not decrease and there is no energy deficiency, since body proteins and glycerol can be used to form glucose, and fat and proteins are used as energy substances.

The digestibility of glucose, sucrose, lactose, dextrin and starch mixed with animal tissues with a properly formulated diet can reach 94%. However, the digestibility of soluble carbohydrates in industrial feed average quality does not exceed 85%.

Although dogs are able to partially digest the raw starch contained in cereals, its digestibility increases significantly with heat treatment carried out during the preparation of food using a certain technology.

Insoluble carbohydrates, collectively called dietary fiber or fiber, include cellulose, hemicellulose, pectin, gums, plant glues, and lignin (a building block of plants).

Various factions dietary fiber differ significantly in their physical and chemical properties. Adding them to food is useful for many diseases, as well as for diarrhea and constipation. Their positive effect is associated with the ability of fibers to retain water and influence the composition of the microflora of the large intestine. Dietary fiber helps to irritate the receptors of the large intestine and stimulate the act of defecation, and also contribute to the formation of more voluminous and soft stool.

Dietary fiber may also influence lipid and carbohydrate metabolism. Pectin and gums can inhibit lipid absorption, thereby increasing the secretion of cholesterol and bile acids and reducing blood lipid concentrations, while cellulose has a very weak effect on serum cholesterol concentrations.

Dietary fiber can have a major impact on blood glucose and insulin levels, which has important in animals with diabetes.

A decrease in the concentration of insulin and glucose in the blood occurs as a result of decreased absorption of glucose in the intestine, slower gastric emptying and changes in the level of secretion of gastrointestinal peptides.

Dietary fiber also affects the absorption of other nutrients. Thus, the higher the fiber content in the diet, the lower the absorption of proteins and energy. Effect of different dietary fibers on absorption minerals not the same. For example, pectin reduces the absorption of certain minerals, but cellulose does not affect this process. Consequently, a diet high in pectins without appropriate mineral supplements can lead to a lack of microelements in the body of animals.

If there is too much fiber in the diet, dogs may experience energy deficiency.

1. "SMALL ANIMAL CLINICAL NUTRITION" L.D. Lewis, M. L. Morris (JR), M. S. Hand, MARK MORRIS ASSOCIATES TOPEKA, KANSAS 1987 (Translated from English and edited by Dr. biological sciences A. S. Erokhina)
2. Feeding dogs. Directory. S.N. Khokhrin, “VSV-Sphinx”, 1996
3. Absolutely everything about your dog, composition. V.N.Zubko M.: Arnadia, 1996

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Carbohydrates solubility - Chemist's Handbook 21

     In terms of their physicochemical properties, polysaccharides that do not have the properties of sugars differ significantly from each other in many respects. Thus, with regard to solubility, there are all gradations from highly soluble to warm water inulin and glycogen to completely insoluble cellulose. Some polysaccharides of this group, for example starch and inulin, under appropriate conditions can be released in the form of spheroidal crystalline particles; most of these carbohydrates (with the exception of glycogen) have a crystalline structure.       Soluble carbohydrates 26-41 including 

Under the action of enzymes or when heated with acids (hydrogen ions serve as a catalyst), starch, like all complex carbohydrates, undergoes hydrolysis. In this case, soluble starch is formed first, then less complex substances - dextrins. The final product of hydrolysis is glucose. The overall reaction equation can be expressed as follows  

Due to the high donor properties of the nitrogen atom, ammonia easily forms hydrogen bonds, as evidenced by its abnormally high boiling point. This leads to the fact that not only ionic, but also many organic (non-ionized) compounds are well dissolved in ammonia. Compounds that form hydrogen bonds (amines, phenols, esters, carbohydrates) are especially easily soluble. For compounds that are poorly soluble in ammonia, complications can be avoided by using cosolvents such as ether, tetrahydrofuran, dioxane or glyme. 

Most carbohydrates, thanks to their groups, are perfectly soluble in water. However, cellulose, the most abundant of the polysaccharides, is insoluble in water and very resistant to hydrolysis. Why After all, the cellulose macromolecule consists of many glucose residues, each of which contains three OH groups. 

Oligosaccharides are complex carbohydrates of relatively low molecular weight, similar in properties to monosaccharides; in most cases they are sweet in taste, soluble and form well-built crystals. When they are hydrolyzed, a small number of monosaccharide molecules (from two to six) are formed from one polysaccharide molecule. 

Aspen wood ground in a vibrating ball mill for 5 hours had a solubility similar to that of spruce wood. Treatment of ground wood with Rohm and Haas Enzyme No. 19 for 3 days yielded 22.4% enzymatic lignin with 14.7% carbohydrates. The solubility of this lignin approached that of enzymatic lignin from spruce wood, except that the former was also soluble in 50% ethanol. After hydrolysis of enzymatic lignin, all types of sugars found in aspen wood were obtained. 

Unlike hydrocarbons, simple sugars (carbohydrates) are highly soluble in water. Explain the reasons, taking into account the differences in the structure of their molecules. For this, compare the structures of glucose ((1H20) and hexane (CH). 

Carbohydrates are soluble. . 26-41 phosphorus.........3.0 

Under the action of enzymes or when heated with acids (hydrogen ions serve as catalysts), starch, like all complex carbohydrates, undergoes hydrolysis. In this case, soluble starch is formed first, then less complex substances - dextrins. Ultimate 

Finally, it should be noted that some researchers combine monosaccharides and oligosaccharides with the term sugars, given the range general properties these groups of carbohydrates (water solubility, sweet taste, etc.). 

Fat molecules are made up of carbon, hydrogen and oxygen, just like carbohydrate molecules. However, their oxygen content is lower than that of carbohydrates, in this sense they are closer to hydrocarbons. In general, both in solubility and energy content, fats are more reminiscent of hydrocarbons than carbohydrates. If the energy intake into the body exceeds its consumption, then the excess amount turns into fat and is deposited in the tissues of the body. If less energy is supplied than needed, then this fat is consumed. 

Higher polysaccharides are complex carbohydrates of high molecular weight, not similar in their properties to monosaccharides, do not taste sweet, are in most cases insoluble and do not form visible crystalline forms. During hydrolysis, a lot of monosaccharide molecules are formed from a polysaccharide molecule (hundreds and thousands). 

Simple carbohydrates include those that are soluble in cold water aldo- and ketohexoses and various pentoses. From the point of view of coal formation, complex 

Various catalytic reactions are divided into homogeneous and heterogeneous catalysis reactions. In cases where the catalyst and reactants form a homogeneous system (that is, they are in the same phase), we are dealing with homogeneous catalysis. As examples, we can point to the catalytic oxidation of CO to CO2 in the presence of water vapor and the oxidation of 303 to 503 in the presence of nitrogen oxide NO2. This type of catalytic reaction also includes the reaction of hydrolysis of soluble carbohydrates in an aqueous solution in the presence of an acid. As we can see, in the first two cases the catalyst and catalyzed substances are in a gaseous state, in the third they form a homogeneous solution. 

By adding water, starch is gradually broken down into other, simpler carbohydrates. It first turns into soluble starch, which is then broken down into dextrins. The hydrolysis of dextrins produces maltose. The maltose molecule is split into two molecules of O-glucose. Thus, the final product of starch hydrolysis is L-glucose  

Mainly acid- and methane-forming bacteria participate in the anaerobic decomposition of organic compounds in wastewater. Carbohydrates and partially fats decompose, forming a mixture of low molecular weight fatty acids, among which acetic, butyric and propionic acid predominate. At the same time, the pH of the environment decreases to 5 and below. Organic acids and soluble nitrogenous substances decompose further, forming ammonium compounds, amines, acid carbonates and a small amount of carbon dioxide 

Carbohydrates are the simplest organic compounds, consisting of carbon, oxygen and hydrogen. Most carbons have the molecular formula CxCHgO). Carbohydrates are divided into simple - monosaccharides and complex - polysaccharides. Examples of carbohydrates are sugar, cellulose starches and pectins (Figure 32). Carbohydrates are the main source of energy for cellular activity. They build strong plant tissue (cellulose) and play the role of reserve nutrients in organisms. Simple carbohydrates are soluble in water. Carbohydrates also include chitin, which acts as a structural material in some plants and animals. 

The content and composition of carbohydrates, which make up a significant part of peat, depend on the type, type, degree of decomposition and conditions of peat formation. The carbohydrate complex is very labile, and its content ranges from 50% for organic matter in high-decomposition peat to 7% for organic matter (OM) in high-decomposition peat (R> 55%). It is represented mainly by polysaccharides of the remains of peat-forming plants. Carbohydrates, soluble in hot water or water-soluble, consist mainly of mono- and polysaccharides and their pectin substances. Peat contains disaccharides that can dissolve in cold water, built from the hexoses sucrose, lactose, maltose, and cellodia. Pectic substances are a complex chemical complex of pentoses, hexoses and uronic acids with a molecular weight of 3,000 to 280,000. 

Hydrolytic method of Kiesel and Semiganovsky (official). The Kiesel and Semiganovsky method is based on the quantitative conversion of cellulose to glucose by treatment with 80% sulfuric acid. Carbohydrates associated with cellulose (soluble carbohydrates, starch, hemicelluloses) are first removed by treatment with dilute hydrochloric acid. Glucose formed from fiber is determined using the Bertrand method. 

The solubility of hydrogen in water at a pressure of 15 MPa is only 2.681 cmUsm at 100 °C, and at 200-225 °C even less (about 2 cmUsm of water). In addition, at high temperatures, the volume of the liquid phase in the reactor decreases, since part of the water evaporates, especially at large hydrogen modules and at significant pressures, when the phenomenon of fugacity becomes significant. The solubility of hydrogen in 10-15% solutions of carbohydrates and polyols is almost the same as in clean water. According to a rough estimate, the amount of hydrogen consumed during hydrogenolysis is 2 orders of magnitude higher than can be simultaneously dissolved in the raw material suspension. That's why 

Relatively recently, N.A. Vasyunina, A.A. Balandin and R.L. Slutskin formulated provisions on a system of catalysts operating in the hydrogenolysis of carbohydrates and many atomic alcohols - on a homogeneous rupture catalyst S-S connections(cracking agent) and a heterogeneous hydrogenation catalyst. At the same time, the catalytic effect in this reaction of soluble metal compounds, for example, iron sulfate, a chelate complex of iron with sugar acids, zinc sulfate, etc., called homogeneous hydrogeolysis cocatalysts, was discovered. The mechanism of their action is discussed in Chap. 3, the addition of homogeneous cocatalysts accelerates hydrogenolysis by 2-3 times, obtaining a hydrogenated product of approximately the same composition as without their use. 

Low molecular weight, sugar-like carbohydrates (oligosaccharides), soluble in water and sweet in taste. 

The hydrolysis of tannins (tannids) produces polyhydric phenols. As a result of the hydrolysis of hemicelluloses, water-soluble polysaccharides (carbohydrates) are formed. general composition SbN120b, S5N10O5. 

Surfactants relative to water are many organic compounds, namely fatty acids with a sufficiently large carbohydrate content, salts of these fatty acids (soaps), sulfonic acids and their salts, alcohols, amines. A characteristic feature of the structure of the molecules of most surfactants is their dnophilicity, i.e. the structure of the molecule from two parts - a polar group and a non-polar hydrocarbon radical. The polar group, which has a significant dipole moment and is easily hydrated, determines the surfactant's affinity for water. The hydrophobic hydrocarbon radical is the reason for the reduced solubility of these compounds. The lowest value of surface tension of an aqueous solution of surfactants can reach 25 erg/cm, i.e., almost equal to surface tension hydrocarbons.  

PENTOSES are monosaccharides containing five carbon atoms in a molecule, with the general formula CdHiOb. They are common in nature, found in free form, and are part of glycosides and polysaccharides (arabans, xylans). Phosphorus derivatives of P. are important intermediate products of carbohydrate metabolism. P. is obtained from natural sources, mainly by hydrolysis of polysaccharides. P. - crystals, highly soluble in water. P. is synthesized from hexoses. 

SUCHAROSE (beet sugar, cane sugar) ChaHaaOc is a carbohydrate, belongs to the group of disaccharides, its molecule consists of residues of glucose and fructose molecules. S. is the most common plant disaccharide; sugar cane and sugar beets are especially rich in S. S. - colorless crystals, well soluble in water, poorly soluble in alcohol. S. is obtained from sugar beets and sugar cane; it can also be obtained from sweet sorghum, corn, etc. 

Discovery of carbohydrates (mono- and disaccharides). Carbohydrates are colorless, highly soluble in water, and neutral. They are easily discovered by the presence of aldehyde, ketone and hydroxyl groups. These groups are opened by the reactions described above. In addition, carbohydrates are optically active compounds whose rotation angle can be measured using a polarimeter. 

Let us now consider the separation on silica gel with a hydroxylated surface of substances that are soluble only in highly polar solvents, using carbohydrates as an example. Carbohydrates are poorly separated on a hydroxylated silica gel surface from highly polar eluents because the silanol groups on the surface are acidic in nature. Of particular importance for the separation of such polar adsorbates from polar eluents on a hydroxylated silica gel surface is the modification of the adsorbent surface with organic modifiers with basic polar groups (electron-donating groups) facing the eluent. Such modifiers can be retained on the surface of a polar adsorbent, as was shown in lectures 4 and 5, by resorting to preliminary adsorption or chemical modification of the surface of an acid-type polar adsorbent. In particular, in lecture 5, the amination of silica gel was considered by carrying out a chemical reaction of the silanol groups of its surface with aminopropyltriethoxysilane [see. reaction (5.23)]. However, it is not necessary to carry out preliminary chemical modification of the surface. You can take advantage of the adsorption of bifunctional substances, in this case diamines, by adding them to the eluent in a concentration that ensures the creation of a sufficiently dense adsorption layer. The molecules of these adsorption modifiers continuously acting on the adsorbent in the column during the passage of the eluent must be bifunctional; in this case, both groups must be donors, so that one of them provides a strong specific interaction with the silanol groups of the silica gel surface, and the other faces the eluent to provide a specific interactions with dosed adsorbates. It is important that the creation of a sufficiently dense monomolecular layer of the modifier is ensured at very low concentrations in the eluent. Such bifunctional modifiers in relation to the acidic silanol groups of silica gel from aqueous or- 

Of great practical importance is the immobilization of enzymes of the hydrolase group, for example, those that convert starch into soluble carbohydrates of low molecular weight (sugars), isomerize glucose into fructose (glucose isomerase), etc. 

A dark blue solution is formed which is called Fehling's liquid; it is used as a reagent for aldehydes, carbohydrates, etc. In the textile industry and mordant dyeing, double oxide potassium antimony salt of tartaric acid (highly soluble) is used - the so-called tartar emetic KOOS-SNON-SNON - OOSbOHgO it is also used in medicine as a means of inducing vomiting. 

Enzymes with amylase activity are widespread in nature. They are found in grains of cereal plants, potato tubers, in the liver, pancreatic secretions, and saliva. With the help of amylases, starch is converted in plant and animal organisms into soluble carbohydrates - maltose and glucose, which are delivered by plant juices or animal blood to places of consumption and, when burned, provide the body with the necessary energy. 

Disaccharides are typical sugar-like carbohydrates; they are solid crystalline substances that are highly soluble in water and have a sweet taste. 

Then check the solubility of the mixture in ether. Most organic compounds are soluble in ether; carbohydrates, amino and sulfonic acids, some polybasic aromatic acids, as well as some amides, urea derivatives and polyols are slightly soluble in ether. 

If it is assumed that the mixture under study contains a polyol, carbohydrate, salt of a carboxylic acid, or a salt of an organic base, then a sample of the mixture is treated with 2 parts of hydrochloric acid. The resulting precipitate is carefully filtered on a Buchner funnel, washed on the filter with water and dried. It may be an aromatic acid; precipitation of oil may indicate that an aliphatic carboxylic acid was present in the mixture. The filtrate may contain a water-soluble polyol or sugar. 

In freshly harvested, technically mature raw materials, in most cases, the synthesis processes are not yet completely completed, so the so-called post-harvest ripening occurs - the conversion of sugar into starch, amino acids into proteins, etc., i.e., the formation of more complex and metabolically less mobile substances, resulting in physiological maturity and a state of rest. Ripening lasts 1.25-1.5 months for potatoes, 1.5-2 months for grain. Freshly harvested corn is usually stored on the cob, with an additional amount of soluble carbohydrates passing from the cob into the grain, which also turns into starch inside it. The ripening of corn grains on the cob ends when normal humidity is reached. 

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what contains fast and slow carbohydrates

Home » Nutrition » Simple and complex carbohydrates: what they contain and which ones are healthy to eat

Carbohydrates are a tricky topic. On the one hand, most healthy eating programs are based on consuming large amounts of carbohydrates - more than 60% of daily norm calories, while minimizing fat intake (for example, the American diet).

On the other hand, many nutritionists believe that reducing the amount of carbohydrates in the diet will not only have a positive effect on weight loss, but will also be beneficial for overall health. Low-carb diets recommend that only 10% of all calories received be allocated to carbohydrates, giving preference to fats and proteins.

Leaving aside all the pros and cons, you need to understand that there are no “good” or “bad” carbohydrates. In fact, there are several types of them, mainly divided into two types: simple and complex. There are 4 kilocalories per 1 gram of carbohydrates; they are a source of energy for the body. Despite the fact that some are absorbed quickly and others slowly, they have the same number of calories.

So, what are simple and complex carbohydrates? In this article, I'll explain the difference between simple and complex carbohydrates to help you make smart choices that will benefit your health. I tried to make this topic as simple and understandable as possible.

Simple carbohydrates

Simple carbohydrates (i.e. sugars) are made up of one or two sugar molecules and have a simple molecular structure, which explains their name. Those. Carbohydrates that consist of one sugar molecule are called monosaccharides:

• Glucose is the most common type of sugar;
• Fructose – found in fruits;
• Galactose – found in dairy products.

Those carbohydrates that contain two sugar molecules are called disaccharides:

• Sucrose – glucose + fructose;
• Lactose – glucose + galactose;
• Maltose is two glucose residues connected to each other.

Many people consider light carbohydrates to be unhealthy due to the fact that they are also known as sugar. However, this is not entirely true. So, if white table sugar (sucrose) can definitely be considered harmful, then the sugar found in fruits (fructose) is quite healthy, as it enters the body along with vitamins, minerals, amino acids and fiber.

Of course, there is a difference between natural simple carbohydrates and refined ones. To understand it, all you need to do is ask yourself the question: “Was this product grown or not?” If the answer is yes, this type of carbohydrate may be better for you than one that is artificially produced.

A table to help you figure it out:

As you can see, fast carbohydrates may also be useful. Of course, if you want to lose weight and live a healthy lifestyle, you should minimize your intake of “bad” carbohydrates.

Complex carbohydrates

This type of carbohydrate contains a complex chain of sugar molecules called polysaccharides (approx. poly - many). They got their name because of their more complex structure; sometimes they are called differently - starches.

It is believed that starch is healthier than simple carbohydrates, but this is not always the case.

Complex carbohydrates include bread, rice, pasta, potatoes (and other vegetables), cereals and grains. These products are in the diet of almost every person; many prefer them due to their low amount of fat.

The fact is that complex carbohydrates can be “good” or “bad”. For example, everyone knows that overuse White bread is harmful to the body, however, it is considered a complex carbohydrate. The same can be said for potato chips!

So what makes slow carbs “good” and “bad”? Typically, it comes down to the amount of processing that the product undergoes. Natural products are called unrefined, and those that have been processed are considered refined.

The former are usually much more useful.

Below is a table that will help you understand the difference:

A processed product loses most of its important nutrients such as vitamins, minerals, amino acids and most importantly fiber...

Fiber

Fiber or dietary fiber is a type of carbohydrate. It is contained in both simple and complex groups. Dietary fiber is difficult for the body to digest and contains virtually no calories, but this does not mean that you need to give it up!

The full name of fiber is starch polysaccharide and it exists in two forms: soluble and insoluble.

Soluble dietary fiber dissolves in water and is found in the skins of plants and grains. Once in the body, they absorb excess bile acid and cholesterol, which is undoubtedly beneficial.

Insoluble dietary fiber does not dissolve in water and is found in the skins of fruits and vegetables, as well as in the husks of grains. Once in the digestive tract, they, like a brush, cleanse your intestines.

You need both types of fiber to keep your body healthy, which amounts to 14 grams per 1,000 calories. If you eat 2,000 calories a day, you should eat 28 grams of fiber.

The easiest way to get dietary fiber is from natural vegetables, fruits and grains.

Switching to a low-carb diet

So, will limiting carbs help you lose weight? Yes, it will help! You will eat fewer calories, and your body will begin to use fat as energy.

But a small amount of carbohydrates is still needed to provide vitamins, minerals and fiber.

You can cut out carbs and get your nutrients from fruits and vegetables (while eliminating grains and refined foods).

There are several types of low-carb diets (called ketogenic diets) that completely limit your carbohydrate intake. You don't have to go that far if you don't want to. The topic of ketogenic diets is best left for another article! Simply eat more vegetables and less bread, rice, pasta and potatoes to help you lose weight. Read my article “Easy Low Carb Diet.”

Conclusion

Now you know the difference between simple carbohydrates and complex carbohydrates, refined carbohydrates and unrefined ones. In addition, you learned a little about fiber. All of this will help you decide which carbohydrates you can eat (unrefined) and which you should avoid (refined) to lose weight and stay healthy.

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Insoluble carbohydrates - Chemist's Handbook 21

     In terms of their physicochemical properties, polysaccharides that do not have the properties of sugars differ significantly from each other in many respects. Thus, with regard to solubility, there are all gradations from inulin and glycogen, which are highly soluble in warm water, to completely insoluble cellulose. Some polysaccharides of this group, for example starch and inulin, under appropriate conditions can be released in the form of spheroidal crystalline particles; most of these carbohydrates (with the exception of glycogen) have a crystalline structure.       Thus, for example, disaccharides - sucrose and lactose, despite their good solubility in water, are not directly absorbed in the intestine. They can be absorbed by the body only after splitting into the corresponding monosaccharides. Being introduced, bypassing the intestines, directly into the blood (parenterally), disaccharides are not used by tissues and are mainly excreted unchanged in the urine. As for polysaccharides, which are even more complex carbohydrates that are insoluble in water, they cannot be directly absorbed by the body. Having been introduced with food through the mouth, starch and glycogen undergo digestion in the digestive tract under the action of appropriate enzymes, i.e., hydrolytic cleavage. At 240 

Glycoproteins. Hydrolyze into simple protein and carbohydrate. Insoluble in water. Dissolves in dilute alkalis. Neutral, do not coagulate when heated. Included in mucus. 

High molecular weight, non-sugar-like carbohydrates (higher polysaccharides), not sweet in taste and insoluble in water. 

Ion exchangers must be sufficiently stable to long-term exposure solutions of sulfuric and hydrochloric acids, alkalis, as well as organic acids and carbohydrates contained in pentose hydrolyzate. Ion exchangers must be practically insoluble in hydrolysates, acids and alkalis. A decrease in the stability of ion exchangers can lead to a sharp decrease in their exchange capacity during operation. Of great importance is the mechanical strength of ion exchangers or the low abrasion of resin grains during its long-term operation when cleaning solutions. Chemical resistance and mechanical strength depend on the resistance of high- 

The isolation of insoluble fibrillar proteins is not associated with particular difficulties, while the purification of individual globular proteins from animal or plant tissues, bacterial cultures and cell suspensions is greatly complicated by the simultaneous presence in solution of many other proteins, carbohydrates, nucleic acids, lipids and others 

Non-sugar-like complex carbohydrates do not have a sweet taste and are either completely insoluble in water or swell in it, forming colloidal solutions. They are high-molecular substances and are also called higher polysaccharides; upon partial hydrolysis, they break down into simpler polysaccharides, or disaccharides, and upon complete hydrolysis, into hundreds and thousands of monosaccharide molecules. 

The advantage of column chromatography is the ability to quantitatively fractionate large quantities of substances without converting them into any derivatives. However, good separation is often only possible at low elution rates, so new types of column chromatography have been developed. Affinity and adsorption chromatography methods are based on the selective adsorption of molecules on an insoluble adsorbent, which contains groups (molecules) that specifically interact with the molecules of the compounds to be purified, for example inhibitors (for the purification of enzymes) or antibodies (for the purification of antigens). Currently, these methods are widely used also used for the separation of carbohydrates. Impurities that do not interact with the adsorbent are removed, and the sugar bound to the adsorbent is then desorbed in a manner that does not lead to its destruction. Desorption can be accomplished by changing the pH, ionic strength of the medium, or using an appropriate inhibitor of the interaction that holds the substance on the adsorbent. To separate a number of polysaccharides, immobilized forms (see section 26.3.7.6) of concanavalin A, which is a phytohemagglutinin (lectin), which specifically interacts with branched polysaccharides of a certain structure, are used; other immobilized phytohemagglutinins are currently used. Column chromatography on polyaromatic-coated supports also finds use in the separation of polysaccharides. Thanks to advances in the production of liquid chromatography media, high pressure chromatographic separation can be carried out quickly and selectively, methods for fractionating small oligosaccharides in less than 1 hour have been described. 

These lignin-carbohydrate complexes were found to be soluble in dimethylformamide, dimethyl sulfoxide and 50% acetic acid. They can be extracted from the wood residue after removing the dioxane-soluble lignin from ground wood. It is noteworthy that the composition of the carbohydrates of the complex is more similar to hemicelluloses than to total carbohydrates, and the composition of the carbohydrates of the insoluble residue is similar to the composition of total carbohydrates. Similar results were reported by McPherson. 

Cellulose is a white substance, insoluble in most common solvents; it is only reduced to an insignificant extent by an aqueous solution of iodine in zinc chloride. The best solvent for fiber is ammonia solution copper oxide, in which it dissolves in significant quantities. Acids again precipitate it from this solution. Concentrated solutions of some metal salts, for example calcium thiocyanate a(S N)2, are also capable of noticeably dissolving this carbohydrate when heated; in addition, it is somewhat soluble in a cold solution of sodium hydroxide (prn -10). 

In the cell walls of most higher plants, along with cellulose, there is another high-molecular substance that gives cells mechanical strength - lignin. Lignin is the residue resulting from the removal of all carbohydrates from cell walls using hydrolyzing agents. This substance is an amorphous powder or yellow-brown fiber, insoluble in water and organic solvents. The elemental composition of lignin in various plants is on average the following: C -63.1%, I -5.9% and 0 - 31%. 

For the technical production of oxalic acid, it is formed in significant quantities by fusing organic substances, especially carbohydrates, with alkali. For this purpose, sawdust with alkali is heated to approximately 200° and after cooling the alloy, the resulting oxalic acid is extracted with water (Dale, 1856). Purification is carried out through insoluble calcium salt. 

Under the general name, carbohydrates unite compounds widely distributed in nature, which include sweet-tasting, water-soluble substances called sugars, and related to them in chemical nature, but much more complex in composition, insoluble and without sweetness. taste compounds such as starch and cellulose (fiber). 

When foreign proteins or other antigenic components, such as macromolecular carbohydrates, penetrate, the antigen-antibody protective mechanism (immune response) begins to operate in the animal's body. During the process of this defensive reaction, the biosynthesis of special proteins, so-called antibodies, is induced, which, through highly specific receptors, combine with antigens to form an insoluble antigen-antibody complex, making the infiltrated antigen safe for the body. 

Simple carbohydrates are usually crystalline solids, but some are known only in the form of viscous syrups. Often, when trying to isolate sugar in crystalline form, they encounter great difficulties (cf. the very slow crystallization of honey or golden syrup, which is a supersaturated solution of glucose and sucrose). Due to the ability to form hydrogen bonds between numerous hydroxyl groups, sugars tend to form harder crystals than conventional organic compounds. They are very soluble in water, moderately soluble in ethanol and completely insoluble in aprotic solvents such as ether, chloroform or benzene. 

The properties of various organic (and inorganic) substances depend on their chemical composition and structure. The size of the molecule of a substance plays a very important role. For example, the sugary substance glucose, which we became familiar with when studying carbohydrates, is colorless crystals that are easily soluble in water and have a sweet taste. In the same chapter, we looked at another carbohydrate - cellulose, built from several thousand glucose units. Cellulose is completely different in properties from glucose; it is insoluble in water, has no taste, and has a fibrous structure. Thus, when moving to compounds whose molecules contain many thousands of atoms, one of the laws of dialectics is brilliantly confirmed, according to which the accumulation of quantitative changes leads to significant qualitative changes. 

Like bacteria, the cells of higher plants and animals are often covered with extracellular material. Thus, plant cells have a rigid wall containing large quantities of cellulose and other polymeric carbohydrates. Cells located on the outer surfaces of plants are covered with a waxy layer. Animal cells are usually protected on the outside by glycoproteins - complexes of carbohydrates with specific cell surface proteins. The space between the cells is filled with cementing substances such as pectin in plants and hyaluronic acid in animals. Insoluble proteins - collagen and elastin - are secreted by connective tissue cells. Cells lying on the surface (epithelial or endothelial) are often bordered on the other side by a thin collagen-containing basement membrane (Fig. 1-3). Often, as a result of the combined action of cells of various types, the deposition of inorganic compounds occurs - calcium phosphate (in bones), calcium carbonate (egg shells and sponge spicules), silicon oxide (Diatom shells), etc. Thus, metabolism is largely occurs outside the cells. 

Polysaccharides. These carbohydrates differ in many ways from mono- and disaccharides - they do not have a sweet taste, are mostly insoluble in water, they are complex high-molecular compounds that, under the catalytic influence of acids or enzymes, undergo hydrolysis to form simpler polysaccharides, then disaccharides and, ultimately as a result, many (hundreds and thousands) of monosaccharide molecules. The most important representatives of polysaccharides are starch and cellulose (fiber). Their molecules are built from -SbNiOb- units, which are the remnants of six-membered cyclic forms of glucose molecules that have lost a water molecule; therefore, the composition of both starch and cellulose is expressed by the general formula (CeHiOa). The difference in the properties of these polysaccharides is due to the spatial isomerism of the monosaccharide molecules that form them; starch is built from a-units, and cellulose is a /3-form of glucose. 

The main reserve polysaccharide in plants is starch. It serves as the main source of carbohydrates in the human diet and, therefore, is of great economic importance; it is produced on an industrial scale. Starch is found in some protozoa, bacteria and algae, but so far the main sources are seeds, fruits, leaves and bulbs of plants, where the starch content ranges from a few percent to >75% (cereal grains). Starch has a granular structure, and the shape of the grains (granules) depends on the source of release. Starch granules can be isolated from plant tissue without destroying them, since they are insoluble in cold water, in which many impurities dissolve. Such granules swell reversibly in cold water, which is used in industrial starch extraction. As the temperature increases, this process becomes irreversible, and eventually the granules are destroyed to form a starch paste. Not all starch granules in the sample are destroyed at the same time. 

Dry substances, including insoluble Carbohydrates in terms of glucose (after hydrolysis) Nitrogen-containing substances, including soluble Fiber Ash substances Other extractive substances (including fat) Solvents (butanol), g/l 2.51 1.15-1.50 0 .72-0.96 0.89-1.0 0.70-0.96 0.08-0.28 0.11-0.14 0.12-0.47 0.07-0.3 100.0 32.6-38.2 35.6-47.7 35-39 3.1-7.6 4.3-6.3 5.4-18.75 

Sullivan determined the lignin content of 36 types of grasses in connection with studying their digestibility and establishing absorption coefficients. He found that the lignin content was in certain correspondence with the digestibility of insoluble carbohydrates and total dry matter. Lignin itself has been found to have significant digestibility, with a digestibility factor in many cases exceeding 10. 

When processing the mother liquor, it was found that there were other substances containing both lignin and carbohydrates. The lignin-carbohydrate complexes found were almost insoluble in wet dioxane. However, if the extraction was prolonged, they were extracted with this solvent in sufficient quantities, contaminating the product. 

Carbohydrates are divided into monosaccharides and polysaccharides. The first group includes glucose and fructose, the second includes cane (beet) sugar (disaccharide), as well as more complex water-insoluble polymers, such as starch and fiber. 

Fermentation of oak moss before extraction with ethyl alcohol improves the odor of the resinoid, but does not increase its yield. In this case, there is a need to dry the raw materials. Extraction of wet moss hydrates the miscella and reduces the strength of the alcohol in circulation, increases the content of insoluble residue in the resinoid due to carbohydrates, and enhances the intensity of its color. 

Polysaccharides. These carbohydrates differ in many ways from MOHO- and disaccharides - they do not have a sweet taste, they are mostly insoluble in water; they are complex high-molecular compounds that, under the catalytic influence of acids or enzymes, undergo hydrolysis to form simpler polysaccharides, then disaccharides and , ultimately, many (hundreds and thousands) of monosaccharide molecules. The most important representatives of polysaccharides are starch and cellulose (fiber). Their molecules are built from units - eHioOj-, which are the remnants of six-membered cyclic forms of glucose molecules that have lost a water molecule and therefore the composition of starch, 

The organic matter of dead phyto- and zooplankton organisms, as well as more organized forms, in the water column and in bottom silts undergoes intensive transformations. Intense microbiological activity is accompanied by the decomposition of the primary substrate and the formation of bacterial biomass. As a result, the content of protein-like compounds decreases by 100-200 times, free amino acids by 10-20 times, carbohydrates by 12-20 times, lipids by 4-8 times. At the same time, the processes of polycondeisation, polymerization of unsaturated compounds, etc. will occur. Arose from unusual biological systems substances that form the basis of the organic part of oil-kerogen. Polymerization of fatty acids, hydroxy acids and unsaturated compounds occurs with the transition of the resulting compaction products into insoluble cyclic and 

In appearance, many carbohydrates differ greatly from each other, for example, there are large differences between grape sugar, which is soluble in water and tastes sweet, starch, which produces colloidal solutions and forms a paste, and, finally, completely insoluble cellulose. However, the study of their chemical structure shows that these substances also have a common basis, since both starch and cellulose can be in various ways broken down to grape sugar. 

The fraction soluble in alcohol is known as native lignin. This beech-derived fraction was found to be free of carbohydrates (see Kawamura and Higuchi). It exhibits all the properties of natural lignin and the reason for the insolubility of the residue is unknown. 

The characteristic property of X. is the ability to form mol. complexes with many salts, compounds, amines, carbohydrates (for example, with glucose - glucocholesterols), proteins, vitamin B3, saponins in the latter case, the compound X. with saponin digitonin precipitates in the form of an insoluble precipitate (this is the basis for the use of X. as an antidote for poisoning saponins). 

Currently, a number of methods are known for the quantitative isolation of holocellulose, consisting of cellulose and hemicelluloses, from wood by transferring lignin and its destruction products into solution. Among these methods, the most widespread are treatment with sodium chlorite in acetic acid, treatment with an aqueous solution of peracetic acid, and chlorination of wood followed by removal of chlorinated lignin with a solution of pyridine or ethanolamine in ethyl alcohol. During these treatments, wood is quantitatively separated into polysaccharides, forming an insoluble fraction and lignin decomposition products that pass into solution. With this treatment, acetic acid residues bound by an ester bond to xylouronides and glucomannan are not cleaved off. The residues of methyl alcohol associated with the carboxyls of uronic acids also by ester bonds are not cleaved. Neither is cleavage observed in significant quantities various types glycosidic bonds that connect monosaccharide and uronic acid residues in hemicellulose macromolecules. The ether bond in 4-0-methylglucuronic acid residues is not destroyed either. This indicates that if a chemical bond exists between lignin and carbohydrates, it should be quite labile and different from those listed above. 

Typically, starch contains about 20% water-soluble fraction called amylose and 80% water-insoluble fraction called amylopectum. These two fractions appear to correspond to different high molecular weight carbohydrates with the formula CnHuOb). When treated with acid or under the influence of enzymes, starch components gradually 

During hydrolysis from the action of dilute mineral acids, upon heating, as well as under the influence of certain enzymes and bacteria, saponins are broken down into carbohydrates (sugar) and water-insoluble aromatic compounds containing one or more hydroxyl groups, called saponins. And. 

As a final example of small molecule binding proteins, it is appropriate to consider lectins. These proteins, most commonly found in (but not limited to) plants, bind carbohydrate derivatives with a significant degree of stereospecificity. Lectins first attracted the attention of researchers for their ability to agglutinate red blood cells by binding membrane glycoproteins. Some lectins are specific to individual blood group substances. Interest in them increased after it was discovered that some of the lectins agglutinate predominantly malignant cells. By immobilization on an insoluble support such as agarose, lectins can be used to purify glycoproteins by affinity chromatography. The most studied lectin is concavalin A; the amino acid sequence of 238 residues and a three-dimensional structure have been determined for this protein. The conformation of concavalin A is quite remarkable. Seven sections of its single polypeptide chain form an antiparallel folded structure, and six subsequent sections form another antiparallel structure perpendicular to the first. The Mn+ ion is coordinated with two water molecules and the side radicals H18-24, 01i-8, Azr-III and Azr-14, forming an octahedron. The Ca + ion, located at a distance of 0.5 nm from Mn +, shares the last two ligands with it, and is also associated with the carbonyl oxygen of Tyr-12, the side radical of Ar-14 and two water molecules and also forms an octahedral configuration. Glucose and mannose residues bind in a deep pocket of 0.6 X 0.75 X 1.8 nm, formed, surprisingly, by hydrophobic residues. 

By adding water, starch is gradually broken down into other, simpler carbohydrates. First, it turns into soluble starch, which then breaks down into smaller fragments called dextrins. Dextrins are solid substances, soluble in water, which are obtained in a technical machine by heating starch to 150 ° C, after wetting it with hydrochloric acid. The shiny crust of the bread consists of dextrins, which are also contained in the entire mass of the bread. The essence of baking lies precisely in the transformation of water-insoluble starch into soluble and easily digestible dextrins. 

Lignin from cooking at 170°C was completely soluble in dioxane. However, lignin from cooking at 100°C was separated into 93.67o dioxane-soluble lignin with 13.48% methoxyls, and 6.4% insoluble lignin-carbohydrate complex with 28.5% carbohydrates. 

Excess peracetic acid in the filtrate was destroyed with colloidal platinum, the solution was stirred in vacuo, and the brown residue was extracted with acetone. In this case, about 14% (calculated on wood) of insoluble material was obtained, consisting mainly of carbohydrates, which, when hydrolyzed with 2.5% sulfuric acid, gave about 60% of reducing sugars. 

The main source of carbon for mold growth seemed to be the carbohydrates still remaining in the fermented liquor. Molds probably also consumed low molecular weight fractions of lignosulfonate, since one mold produced an insoluble lignin residue (lignin was determined by the Klason method with 727 sulfuric acid) containing 8.3% methoxyls. Molds grown in a normal nutrient medium produced residues devoid of methoxyls. 

serve as the main source of energy. The body receives approximately 60% of its energy from carbohydrates, the rest from proteins and fats. Carbohydrates are found mainly in foods of plant origin.

Depending on the complexity of their structure, solubility, and speed of absorption, carbohydrates in food products are divided into:

simple carbohydrates- monosaccharides (glucose, fructose, galactose), disaccharides (sucrose, lactose);

complex carbohydrates- polysaccharides (starch, glycogen, pectin, fiber).

Simple carbohydrates easily dissolve in water and are quickly absorbed. They have a pronounced sweet taste and are classified as sugars.

Simple carbohydrates. Monosaccharides.
Monosaccharides are the fastest and highest quality source of energy for processes occurring in the cell.

Glucose- the most common monosaccharide. It is found in many fruits and berries, and is also formed in the body as a result of the breakdown of disaccharides and starch in food. Glucose is most quickly and easily used in the body to form glycogen, to nourish brain tissue, working muscles (including the heart muscle), to maintain required level blood sugar and creation of liver glycogen reserves. In all cases, with large physical stress glucose can be used as an energy source.

Fructose has the same properties as glucose and can be considered as a valuable, easily digestible sugar. However, it is absorbed more slowly in the intestines and, entering the blood, quickly leaves the bloodstream. Fructose in a significant amount (up to 70 - 80%) is retained in the liver and does not cause oversaturation of the blood with sugar. In the liver, fructose is more easily converted into glycogen compared to glucose. Fructose is absorbed better than sucrose and is more sweet. The high sweetness of fructose allows you to use smaller quantities to achieve the required level of sweetness in products and thus reduce the overall consumption of sugars, which is important when building food rations limited calorie intake. The main sources of fructose are fruits, berries, and sweet vegetables.

The main food sources of glucose and fructose are honey: the glucose content reaches 36.2%, fructose - 37.1%. In watermelons, all sugar is represented by fructose, the amount of which is 8%. Fructose predominates in pome fruits, and glucose predominates in stone fruits (apricots, peaches, plums).

Galactose It is a product of the breakdown of the main carbohydrate in milk - lactose. Galactose in free form food products does not occur.

Simple carbohydrates. Disaccharides.
Of the disaccharides in human nutrition, sucrose is of primary importance, which, upon hydrolysis, breaks down into glucose and fructose.

Sucrose. The most important food source is cane and beet sugar. The sucrose content in granulated sugar is 99.75%. Natural sources sucroses are melons, some vegetables and fruits. Once in the body, it easily decomposes into monosaccharides. But this is possible if we consume raw beet or cane juice. Regular sugar has much more complex process assimilation.

This is important! Excess sucrose affects fat metabolism, increasing fat formation. It has been established that with an excess intake of sugar, the conversion of all nutrients (starch, fat, food, and partly protein) into fat increases. Thus, the amount of incoming sugar can serve to a certain extent as a factor regulating fat metabolism. Excessive sugar consumption leads to disruption of cholesterol metabolism and an increase in its level in the blood serum. Excess sugar negatively affects function intestinal microflora. This increases the specific gravity putrefactive microorganisms, the intensity of putrefactive processes in the intestines increases, and flatulence develops. It has been established that these deficiencies manifest themselves to the least extent when consuming fructose.

Lactose (milk sugar)- the main carbohydrate of milk and dairy products. Its role was very significant in the early childhood when milk serves as a staple food. In the absence or reduction of the lactose enzyme, which breaks down lactose into glucose and galactose, milk intolerance occurs in the gastrointestinal tract.

Complex carbohydrates. Polysaccharides.
Complex carbohydrates, or polysaccharides, are characterized by a complex molecular structure and poor solubility in water. Complex carbohydrates include starch, glycogen, pectin and fiber.

Maltose (malt sugar)- an intermediate product of the breakdown of starch and glycogen in the gastrointestinal tract. In free form in food products, it is found in honey, malt, beer, molasses and sprouted grains.

Starch- the most important supplier of carbohydrates. It is formed and accumulates in the chloroplasts of the green parts of the plant in the form of small grains, from where, through hydrolysis processes, it turns into water-soluble sugars, which are easily transported through cell membranes and thus enter other parts of the plant, seeds, roots, tubers and others. In the human body, starch from raw plants gradually breaks down in the digestive tract, and the breakdown begins in the mouth. Saliva in the mouth partially converts it into maltose. This is why chewing food well and moistening it with saliva is extremely important. Try to use foods containing natural glucose, fructose and sucrose more often in your diet. The largest amount of sugar is found in vegetables, fruits and dried fruits, as well as sprouted grains.

Starch has basic nutritional value. Its high content is largely determined by nutritional value grain products. Starch accounts for about 80% of human diets total number carbohydrates consumed. The conversion of starch in the body is mainly aimed at satisfying the need for sugar.

Glycogen in the body it is used as an energy material to power working muscles, organs and systems. Glycogen restoration occurs through its resynthesis at the expense of glucose.

Pectins refer to soluble substances that are absorbed in the body. Modern research has shown the undoubted importance of pectin substances in the diet of a healthy person, as well as the possibility of using them with therapeutic purpose for some diseases mainly of the gastrointestinal tract.

Fiber Its chemical structure is very close to polysaccharides. Cereal products are characterized by a high fiber content. However, in addition to the total amount of fiber, its quality is important. Less coarse, delicate fiber is easily broken down in the intestines and is better absorbed. Fiber from potatoes and vegetables has these properties. Fiber helps remove cholesterol from the body.

The need for carbohydrates is determined by the amount of energy expenditure. The average need for carbohydrates for those who are not engaged in heavy physical labor is 400 - 500 g per day. In athletes, as the intensity and severity of physical activity increases, the need for carbohydrates increases and can increase up to 800 g per day.

This is important! The ability of carbohydrates to be a highly efficient source of energy underlies their protein-sparing action. When a sufficient amount of carbohydrates is supplied with food, amino acids are used only to a small extent in the body as energy material. Although carbohydrates are not essential nutritional factors and can be formed in the body from amino acids and glycerol, the minimum amount of carbohydrates daily ration should not be lower than 50 - 60g to avoid ketosis, an acidic state of the blood that can develop if primarily fat reserves are used for energy production. A further reduction in the amount of carbohydrates leads to severe disturbances in metabolic processes.

Eating too many carbohydrates, more than the body can convert into glucose or glycogen, results in obesity. When the body needs more energy, fat is converted back to glucose and body weight decreases. When creating food rations, it is extremely important not only to satisfy human needs for required quantity carbohydrates, but also to select optimal ratios of qualitatively different types of carbohydrates. The most important thing to consider is the ratio in the diet easily digestible carbohydrates(sugars) and slowly absorbed (starch, glycogen).

When significant amounts of sugars are taken from food, they cannot be completely stored as glycogen, and their excess is converted into triglycerides, promoting increased development of adipose tissue. Increased levels of insulin in the blood help speed up this process, since insulin has a powerful stimulating effect on fat deposition.

Unlike sugars, starch and glycogen are broken down slowly in the intestines. The blood sugar level increases gradually. In this regard, it is advisable to satisfy carbohydrate needs mainly through slowly absorbed carbohydrates. They should account for 80 - 90% of the total amount of carbohydrates consumed. Limiting easily digestible carbohydrates is of particular importance for those who suffer from atherosclerosis, cardiovascular diseases, diabetes, and obesity.

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Carbohydrates include cellulose, hemicellulose, palisaccharides (starch, inulin), disaccharides (cane sugar), and monsaccharides (glucose, fructose, lactose). Other compounds included in the feed, containing, as well as carbohydrates, carbon, hydrogen and oxygen, include pentoses, encrusting substances (lignin, cutin), organic acids, pigments, pectin substances, glucosides and a number of others that are found in plant and animal products in small quantities.

Typically, among these substances, diverse in composition and physiological significance, the following groups are distinguished: crude fiber - it includes cellulose, hemcellulose, lignin and other encrusting substances; soluble carbohydrates - starch, inulin, sugars; nitrogen-free extractive substances, which includes everything else; Usually soluble carbohydrates are not defined, but they are combined with a group of nitrogen-free extractives, abbreviated by the initial letters BEV.

Crude fiber is a compound that largely determines the energy nutritional value of feed and the content of organic substances that are useful for animals and capable of oxidation.

The nutritional value of crude fiber is affected by the degree of lignification, coarseness, which is caused by the content of lignin in it, especially its insoluble forms, and the degree of cellulose fibrousness. Crude fiber, depending on its presence in plants and the phase of plant development, is digested and absorbed completely differently. In the initial periods of plant development, in the phase of basal leaves, crude fiber is digested by 70-85% and is absorbed no worse than soluble carbohydrates. At this time, it consists mainly of hemicellulose, an amorphous cellulose; Lignin is present mainly in its soluble forms. As plants age, following changes: more cellulose accumulates, it becomes fibrous, joins into dense bundles (inaccessible to digestive juices), and complexes with insoluble forms of lignin. As a result, the digestibility of feed is sharply reduced and the use of digested organic matter in the feed by animals is significantly impaired. So, for example, in one of foreign experiences The digestibility of timothy organic matter in May was 85%, and at the end of June it was 45%. On average, for each day of plant development, digestibility decreased by 0.5%.

The process of decreasing the digestibility of fiber is accompanied by a simultaneous increase in its content in dry matter. If in initial phases development in plants contains crude fiber 8-14%, then in the final (shedding of seeds, drying of plants) up to 45%. During plant development, the specific gravity of lignin in dry matter increases. However, of greater importance in reducing the energy nutritional value of a plant is the fact that lignin is converted into insoluble forms and combines with cellulose, thereby sharply reducing the digestibility of crude fiber and other organic substances that make up the plant.

When the dry matter of feed contains 45% fiber, its digestibility turns out to be low, equal to 40%, and the nutritional value of the dry matter sharply decreases. Feeds such as winter straw are unproductive, as they sharply reduce animal productivity. When the crude fiber content increases to 45-55% and higher (as in branches, sawdust and other wood waste, in peat) products and materials are no longer suitable for feeding animals.

Fiber acts as a ballast substance that creates bulk in the food mass. The fact is that when animals eat less than 2 kg of dry matter per hundredweight of live weight, digestive processes are disrupted, which negatively affects the absorption of nutrients and the health of animals. Therefore, giving low-nutrient or even almost non-nutritious foods has a positive effect on the condition of animals. The insufficient volume of the diet also affects the formation of cultivated habits in animals - pigs gnaw farm floors, wooden parts of feeders, horses swallow air (biting).

Another positive property of raw fiber is the ability to warm animals well in winter and to generate additional amounts of thermal energy in the body. This happens due to the fact that microorganisms of the digestive tract, primarily in ruminants, when decomposing and using fiber, emit a lot of heat - about 2500 kcal per 1 kg of digested fiber. This circumstance leads to the fact that in winter, at low temperatures, livestock more willing eats barn and other roughage, and in spring and summer refuses straw.

Is it possible to artificially, through processing, change the nutritional value of feed, as well as non-feed products? It turns out it's possible. The fact is that in terms of gross caloric content, roughage is the same as concentrates, containing 4400 kcal per 1 kg. Their low nutritional value is due to poor digestibility, as well as unsatisfactory assimilation of digested substances. If you treat roughage with an alkaline solution of sufficiently active alkalis - caustic soda, lime (boiling liquid) with the presence of a sufficient quantity of hydroxyl groups (OH) and a pH number of at least 11-12, then the separation of cellulose from lignin occurs, the fibrous structure of cellulose becomes amorphous, in To a certain extent, lignin dissolves, as well as silicon salts along the way. At the same time, the nutritional value of the dry matter of roughage increases sharply.

It turns out that a similar treatment with an alkaline solution can turn non-feed products into feed. Thus, treatment of wood flakes, aspen and birch sawdust with an alkaline solution made it possible to turn them into a product that is eaten not only by cattle, but also by pigs.

Soluble carbohydrates - starch, inulin (in tubers earthen pear), cane sugar, glucose, fructose, lactose are easily digested and well absorbed. They serve in the animal’s body as material for the formation of mechanical and thermal energy and for the synthesis of fat. Animal body cells contain monosaccharides, blood contains glucose, and milk contains milk sugar (lactose). Animal starch (glycogen) is available in very limited quantities in the liver, where it plays the role of an intermediate compound. Soluble carbohydrates are present mainly in grains, seeds, roots and tubers, making up up to 80% of their dry matter. Soluble carbohydrates are the best sources of fat formation in the body of animals, since the process of fat synthesis from them occurs more efficiently than from proteins and fats in feed, and the quality of fat is characteristic of a given animal species.

In ruminants, an excess of soluble carbohydrates with a lack of protein in the feed leads to digestive dystrophy and poorer utilization of nutrients due to reduced activity of microorganisms in the gastrointestinal tract.

Feeds rich in easily soluble carbohydrates are used in significant quantities during the final period of fattening animals, in particular pigs, when increased fat deposition occurs. Soluble carbohydrates are more readily used by monogastric animals than by ruminants, where they partially provide nutrition for rumen microorganisms.

Pentoses and pectin substances are similar in quality to soluble carbohydrates; they are well digested and used by animals. Found in plant foods.

Organic acids in feed are found in the form of lactic, acetic, propionic, and mayolic. The content of organic acids in dry matter for its successful use should not exceed 6%. With a higher content and a pH value below 3.6 - 3.8, the palatability of such feed, for example silage, decreases. The fact is that animals, as a rule, refuse to eat silage if the amount of free organic silage exceeds 100 g per hundredweight of live weight of ruminants and 50-80 g per hundredweight of pigs.

Typically organic acids in feed are more are formed due to fermentation. Therefore, there are a lot of them in silage, stillage, and beer grains.

The most desirable in feed is lactic acid. It encourages a more energetic secretion of digestive juices and promotes a good appetite. Silage with sufficient lactic acid does not have a pronounced sour odor, since lactic acid is not volatile. Acetic acid, as a volatile acid, gives feed a corresponding sour odor. Propionic acid is found in feed in smaller quantities than acetic and lactic acid. It is good for animals. Butyric acid is undesirable in silage. Its presence is a sign of butyric acid fermentation, leading to the decomposition of silage. Good silage contains no butyric acid. In the total amount of organic acids in the silage, the share of butyric acid should not exceed 20%.

In the rumen of ruminants, as a result of the vital activity of microorganisms (bacteria, ciliates), organic acids are formed - acetic, propionic, butyric, valeric and in small quantities others. These acids are absorbed into the blood and serve as a source of synthesis of various organic substances of the body. In particular, acetic acid goes into the formation of uterine fat. Typically, among the volatile fatty acids formed in the rumen, 62-73% are acetic, 18-28% propionic, 7-16% butyric.

Carbohydrates provide the body with energy and play an important role in regulating the gastrointestinal tract. Carbohydrates are divided into two groups depending on their solubility: soluble And insoluble carbohydrates.

Monosaccharides may have alpha or beta configuration. Carbohydrates consisting of α-monosaccharides, are easily digested by enzymes in the digestive tract of animals and are classified as soluble carbohydrates.

Carbohydrates consisting of β-monosaccharides, are resistant to the action of endogenous digestive enzymes and are classified as insoluble carbohydrates. However, in some animal species, microorganisms in the digestive tract produce the enzyme cellulase, which breaks down insoluble carbohydrates into CO 2, flammable gases and volatile fatty acids.

Volatile fatty acids(VFA) are the most important energy source for herbivores. Non-herbivores, such as dogs, have limited microbial digestive processes, so insoluble carbohydrates have no energy value. They reduce the energy nutritional value of the diet.

Therefore, foods containing high levels of insoluble carbohydrates should not be used for dogs with high energy needs (growth, late stages of pregnancy, lactation, stress, work). At the same time, such feeds are successfully used to reduce and control excess body weight in animals prone to obesity.

Alpha bonds in all carbohydrates, with the exception of disaccharides, are broken down by the digestive enzyme - amylase. This enzyme is secreted by the pancreas and in some animal species it is also secreted in small quantities by the salivary glands.

Disaccharides (maltose, sucrose, lactose) are broken down into monosaccharides using special enzymes - disaccharidases, such as: maltase, isomaltase, sucrase And lactase. These enzymes are contained in the villi of the brush border of intestinal epithelial cells. If the brush border structure is damaged or these cells lack these enzymes, then animals are unable to metabolize disaccharides.

With this pathology, disaccharides remain in the intestine and are used by bacteria, stimulating their reproduction and increasing the osmolarity of the intestinal contents, which leads to the release of water into the intestinal lumen and diarrhea (diarrhea). Feeds containing disaccharides, such as milk containing lactose, lead to increased diarrhea if used to feed sick animals.

Soluble carbohydrates are a readily available source of energy and are found in fairly high proportions in many diets, except those that consist almost entirely of meat, fish or animal tissue. When there is an excess content of soluble carbohydrates in the diet, some of the carbohydrates are stored in the body in the form of glycogen or adipose tissue for later use. Therefore, excess carbohydrates in the diet predisposes animals to obesity.

In the absence of carbohydrates in the diet of animals, the concentration of glucose in their blood does not decrease and there is no energy deficiency, since body proteins and glycerol can be used to form glucose, and fat and proteins are used as energy substances.

The digestibility of glucose, sucrose, lactose, dextrin and starch mixed with animal tissues with a properly formulated diet can reach 94%. However, the digestibility of soluble carbohydrates in industrial feed of average quality does not exceed 85%.

Although dogs are able to partially digest the raw starch contained in cereals, its digestibility increases significantly with heat treatment carried out during the preparation of food using a certain technology.

Insoluble carbohydrates, collectively known as “dietary fiber” or “fiber”, include cellulose, hemicellulose, pectin, gums, mucilage And lignin(being a structural element of plants).

Different fractions of dietary fiber differ significantly in their physical and chemical properties. Adding them to food is useful for many diseases, as well as for diarrhea and constipation. Their positive effect is associated with the ability of fibers to retain water and influence the composition of the microflora of the large intestine. Dietary fiber helps to irritate the receptors of the large intestine and stimulate the act of defecation, and also contribute to the formation of more voluminous and soft stool.

Dietary fiber can also affect lipid and carbohydrate metabolism. Pectin and gums can inhibit lipid absorption, thereby increasing the secretion of cholesterol and bile acids and reducing blood lipid concentrations, while cellulose has a very weak effect on serum cholesterol concentrations.

Dietary fiber can have a major effect on blood glucose and insulin levels, which is important in diabetic animals.

A decrease in the concentration of insulin and glucose in the blood occurs as a result of decreased absorption of glucose in the intestine, slower gastric emptying and changes in the level of secretion of gastrointestinal peptides.

Dietary fiber also affects the absorption of other nutrients. Thus, the higher the fiber content in the diet, the lower the absorption of proteins and energy. The effect of different dietary fibers on mineral absorption is not the same. For example, pectin reduces the absorption of certain minerals, but cellulose does not affect this process. Consequently, a diet high in pectins without appropriate mineral supplements can lead to a lack of microelements in the body of animals.

If there is too much fiber in the diet, dogs may experience energy deficiency.

Sources

1. "SMALL ANIMAL CLINICAL NUTRITION" L.D. Lewis, M. L. Morris (JR), M. S. Hand, MARK MORRIS ASSOCIATES TOPEKA, KANSAS 1987 (Translation from English and editing by Doctor of Biological Sciences A. S. Erokhin)
2. Feeding dogs. Directory. S.N. Khokhrin, “VSV-Sphinx”, 1996
3. Absolutely everything about your dog, composition. V.N.Zubko M.: Arnadia, 1996