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Hydrolysis of starch

Starch (C6H10O5) n is a polysaccharide that consists of two fractions: 25% linear amylose and 75% branched amylopectin. It is formed in the light in plants in the process of photosynthesis.

This substance is a white powder that does not dissolve in cold water, forming a slurry. After settling the suspension, a white precipitate is deposited on the bottom of the tank, and the water can easily be drained. After drying, starch restores all its properties.

In hot water, this substance forms a colloidal solution - it is such a sticky liquid, which is also called starch paste and is often used in everyday life as a gluing agent. And on this property of it, the preparation of kissels and some desserts is based.

Starch is a chemically inert substance. In order for it to react, it is necessary to participate in this process of catalysts.

Its physical and chemical properties are based on the use of this substance. Thus, starch and its derivatives are often used in the food, textile and paper industries. And for living organisms, it plays an important role.

To use this organic substance for industrial purposes, it is subjected to chemical action. Hydrolysis of starch is a process of exchange between substance ions and water, which can be enzymatic or acidic.

Chemical hydrolysis of starch is a catalytic reaction, as it occurs when heated in the presence of inorganic acids. During this chemical reaction , glucose is formed, which can be expressed by the equation:
(C6H10O5) n + nH2O + (cat H2SO4 + t °) = nC6H12O6.

But recently, enzymatic hydrolysis of starch has become very popular. Using special technologies, it produces ethyl alcohol, molasses and glucose in the same way as in chemical hydrolysis.

The advantage of this process is that for it starch-containing plants, for example, rye, potatoes, corn, rice and some others are taken as the starting material. These source codes, moreover, contain in their composition amylolytic enzymes, which are used in the process of hydrolysis.

For example, such enzymes are isoamylases and pullulanases, glucolinases. Enzymes are natural catalysts that accelerate the course of chemical reactions. Schematically, the process of starch degradation under the action of enzymes looks like this: starch → soluble starch (amylose) → oligosaccharides (dextrins) → disaccharide (maltose = malt) → α-glucose. It can also be expressed by the equation:
(C6H10O5) n + nH2O + (cat-enzyme) = nC6H12O6

Clearly you can see that there was a chemical hydrolysis, having conducted an experiment. We boil a mixture of starch paste with sulfuric acid. We check whether hydrolysis occurred - dripping iodine. If the reaction is negative, that is, there is no blue or violet staining, then hydrolysis has occurred.

Now we prove that the product of hydrolysis is glucose. Add to the solution obtained alkali and copper (II) sulfate (CuSO4). The precipitate of copper hydroxide does not drop out, the solution acquires a bright blue color. Heat and see the formation of a sediment of terracotta (brick) color - this means that there is glucose in the solution, which was formed during hydrolysis.

In the human body, enzymatic hydrolysis of starch also occurs. This process is very important, as it generates carbohydrates, in particular, glucose. It oxidizes in every cell of the body, forming water and carbon dioxide, while releasing the energy that is necessary for the normal functioning of the body.

Hydrolysis of starch with the help of enzymes begins in the mouth when chewing food. Human saliva contains an enzyme - amylase, under the action of which the starch is split into simpler components - dextrins. This process a person can even feel. After all, if you chew bread for a long time, a sweetish taste appears in your mouth, which indicates that the process of hydrolysis of starch began. Excess glucose, which is formed during hydrolysis, is deposited in the liver as a reserve nutrient - glycogen.

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