A monomer of starch is what compound?

Chemistry distinguishes three types of carbohydrates. This is starch, fiber and glucose. Starch is the most important representative of the group of natural carbohydrates. Its synthesis occurs in all plants, it is the main source of energy for the human body. What is the monomer of starch? About this below.

Applications

Since very old times, starch is widely used in the field of medicine. In medical practice, it is used as an enveloping agent for ulcerative lesions and inflammatory processes of the mucosa of such organs as the intestine and stomach. Analytical and pharmaceutical chemistry uses starch as the main indicator for iodine. Pharmaceutical technology uses starch as a filler, binding agent. But what kind of compound is a monomer of starch, it is interesting to many. Let's look at this article.

The only scientific center of starch-and-flown industry in our country is represented by the All-Russian Research Institute of Starch Products. It is located in the Moscow region, and its main task is the process of developing new technologies for the production of starch from cereals and potatoes, modified starch, glucose and molasses, glucose-fructose syrups and dietary products without protein. In addition to research, VNIIK is engaged in the design of specialized equipment that is used in the starch industry. Thus, VNIIK's activities affect a large scientific area: from research to production development.

Below we will consider what is the monomer of starch.

Composition

If starch is considered from the point of view of science, then it is a huge amount of simple sugars that are collected in a chain. Such chains can be linear or branched. The main molecule of each such chain is glucose, it is the substance that is assigned the role of the main source of energy in the human body.

Any such long chain, consisting of glucose, has the property of bending, twisting and folding many times. As a result, the formation of microscopic granules, which outwardly resemble grains of flour. Incidentally, the flour is essentially a mixture consisting of starch and various concomitant substances. That is, glucose is the monomer of starch.

If you take starch in your hand and try to squeeze it in your fist and rub it between your fingers, you will hear a specific creak. A similar sound occurs in the process of friction of the starch particles against each other: they have a solid structure, and fractures do not occur with such an effect.

In plant organisms, starch is formed as a result of consecutive connection of a sufficiently large number of glucose molecules. Before this, glucose is synthesized from carbon dioxide and water. After all, it is a monomer of a starch molecule.

Properties of starch

In most plants, starch is the main accumulator of energy reserves. It is this property that can explain the fact that the most active store of starch takes place in roots, tubers and seeds. Wheat or corn grain is more than half starch in composition.

Let us consider in more detail the chemical composition and structure of starch. Starch, along with glycogen and cellulose, is one of the most important representatives of the group of polysaccharides.

Polysaccharides

Polysaccharides are substances that are carbohydrate polymers, which consist of a large number of monosaccharide units. Their number can vary from a few tens to several thousand. That is, it is a high-molecular compound (IUD), and the starch monomer is glucose.

The general formula

The general formula for macromolecular compounds can be written as follows:

(C ₆ H ₁₀ O ₅ ) _n, where n in this case can reach hundreds and thousands.

Externally, starch is known to everyone - it is a substance of white color, which consists of grains of small size. Starch does not dissolve in cold water, but is soluble in hot water. Has the property of swelling. The resulting viscous solution solutions after cooling are converted into a gelatinous mass called a paste.

In the composition of starch there are two fractions: amylopectin and amylose. These two fractions are formed by α-D-glucose. They differ among themselves not only by the structure of the chain itself, but also by the number of glucose residues. These monosaccharide residues are connected by bridges from oxygen. In the chain formation process, the glycoside hydroxyl of one molecule interacts with the alcohol hydroxyl of another molecule. When the starch reacts with the iodine solution, a characteristic coloration of blue appears. That is, the reaction is of a qualitative nature. Staining disappears if the solution is heated, and occurs if it is cooled.

Now it is clear which compound is the monomer of starch.

Amylose is a polysaccharide with a linear chemical chain, it is built from several thousand hexoses (glucose residues), which are connected together by an α-glycosidic bond. X-ray diffraction analysis suggests that the amylose molecule has a spiral arrangement. In each coil of the spiral there are exactly 6 links formed by monosaccharides. On average, there are about 50 turns in such a spiral.

Inside such a spiral structure there is a channel, the diameter of which is about 0.5 nanometers. Inside the channel, other molecules may be located that are appropriate in size. Such a design is a special complex, which is called inclusion connections. The amylose and iodine compound having a blue color is just one of these structures. What is the monomer of starch, we found out earlier.

Amylose and amylopectin

Amylose and amylopectin have absolutely the same chemical composition, the main difference between them is the spatial structure. The molecule of amylose is constructed threadlike, that is, linearly, and the molecule of amylopectin has a branched structure.

Between the branch points there are approximately 20-25 hexosomes. In total, the amylopectin macromolecule may contain about 6,000 or more units derived from monosaccharides.

As a rule, 10-20% of starch consists of bound water. If it is heated quickly, hydrolytic decomposition of the macromolecules will occur, and as a result, smaller chains of molecules will be formed.

Starch is the main source of carbohydrates in the human diet, which is why it has the greatest importance in the form of food products: bread, potatoes, cereals. In large quantities, starch is used in industry, for example, it is used for gluing tissues (during sizing), gluing paper and cardboard, producing dextrin glue. In the field of analytical chemistry, starch is used as an indicator for the iodometric method of titration.

We found out which substance is the monomer of starch.