Disaxaridы

Disaccharides (disaccharides, oligosaccharides) is a group of carbohydrates, the molecules of which consist of two simple sugars combined into one molecule by a glycosidic bond of a different configuration. The generalized formula of disaccharides can be represented as C₁₂Н₂₂О₁₁.

Depending on the structure of molecules and their chemical properties, reducing and non-reducing disaccharides are distinguished. Reducing disaccharides include lactose, maltose, and cellobiose; non-reducing disaccharides include sucrose and trehalose.

Chemical properties

Disugar are solid crystalline substances. Crystals of various substances are colored from white to brown. They dissolve well in water and alcohols, have a sweet taste.

During the hydrolysis reaction, glycosidic bonds are broken, as a result of which disaccharides break down into two simple sugars. In the reverse process of hydrolysis, condensation fuses several molecules of disaccharides into complex carbohydrates – polysaccharides.

Lactose – milk sugar

The term “lactose” is translated from Latin as “milk sugar”. This carbohydrate is named so because it is found in large quantities in dairy products. Lactose is a polymer consisting of molecules of two monosaccharides – glucose and galactose. Unlike other disaccharides, lactose is not hygroscopic. Get this carbohydrate from whey.

Range of application

Lactose is widely used in the pharmaceutical industry. Due to the lack of hygroscopicity, it is used for the manufacture of easily hydrolysable sugar-based drugs. Other carbohydrates, which are hygroscopic, quickly become damp and the active medicinal substance in them quickly decomposes.

Milk sugar in biological pharmaceutical laboratories is used in the manufacture of nutrient media for growing various cultures of bacteria and fungi, for example, in the production of penicillin.

Lactose isomerized in pharmaceuticals to produce lactulose. Lactulose is a biological probiotic that normalizes intestinal motility in case of constipation, dysbacteriosis and other digestive problems.

Useful Properties

Milk sugar is the most important nutritious and plastic substance, vital for the harmonious development of the growing organism of mammals, including the baby. Lactose is a nutrient medium for the development of lactic acid bacteria in the intestine, which prevent the development of putrefactive processes in it.

Of the beneficial properties of lactose, it can be distinguished that, with a high energy intensity, it is not used to form fat and does not increase the level of cholesterol in the blood.

Possible harm

Lactose does not harm the human body. The only contraindication to the use of products containing milk sugar is lactose intolerance, which occurs in people with a deficiency of the lactase enzyme, which breaks down milk sugar into simple carbohydrates. Lactose intolerance is the cause of impaired absorption of dairy products by people, more often adults. This pathology manifests itself in the form of symptoms such as:

• nausea and vomiting;
• diarrhea;
• bloating;
• colic;
• itching and rashes on the skin;
• allergic rhinitis;
• puffiness

Lactose intolerance is most often physiological, and it is associated with age-related lactase deficiency.

Maltose – malt sugar

Maltose, which consists of two glucose residues, is a disaccharide produced by cereals to build the tissues of their embryos. Less maltose is found in the pollen and nectar of flowering plants, and in tomatoes. Malt sugar is also produced by some bacterial cells.

In animals and humans, maltose is formed by the breakdown of polysaccharides – starch and glycogen – with the help of the enzyme maltase.

The main biological role of maltose is to provide the body with energy material.

Possible harm

Harmful properties are shown by maltose only in those people who have a genetic deficiency of maltase. As a result, in the human intestine, when eating foods containing maltose, starch or glycogen, underoxidized products accumulate, provoking severe diarrhea. Excluding these foods from the diet or taking enzyme preparations with maltase helps to level the manifestations of maltose intolerance.

Sucrose – cane sugar

Sugar, which is present in our daily diet, both in its pure form and as part of various dishes, is sucrose. It is made up of glucose and fructose residues.

In nature, sucrose is found in a variety of fruits: fruits, berries, vegetables, as well as in sugar cane, from where it was first mined. The breakdown of sucrose begins in the mouth and ends in the intestines. Under the influence of alpha-glucosidase, cane sugar is broken down into glucose and fructose, which are quickly absorbed into the blood.

Useful Properties

The benefits of sucrose are obvious. As a very common disaccharide in nature, sucrose serves as a source of energy for the body. Saturating the blood with glucose and fructose, cane sugar:

• ensures the normal functioning of the brain – the main consumer of energy;
• is a source of energy for muscle contraction;
• increases the efficiency of the body;
• stimulates the synthesis of serotonin, due to which it improves mood, being an antidepressant factor;
• participates in the formation of strategic (and not only) fat reserves;
• takes an active part in carbohydrate metabolism;
• supports the detoxification function of the liver.

The beneficial functions of sucrose appear only when it is consumed in limited quantities. It is considered optimal to consume 30-50 g of cane sugar in meals, drinks or in its pure form.

Harm when abused

Exceeding the daily intake is fraught with the manifestation of the harmful properties of sucrose:

• endocrine disorders (diabetes, obesity);
• destruction of tooth enamel and pathologies on the part of the musculoskeletal system as a result of a violation of mineral metabolism;
• sagging skin, brittle nails and hair;
• deterioration of the skin condition (rash, acne formation);
• suppression of immunity (effective immunosuppressant);
• suppression of enzyme activity;
• increased acidity of gastric juice;
• violation of the kidneys;
• hypercholesterolemia and triglyceridemia;
• acceleration of aging.

Since B vitamins are actively involved in the process of absorption of sucrose breakdown products (glucose, fructose), excessive consumption of sweet foods is fraught with a deficiency of these vitamins. A prolonged lack of B vitamins is dangerous with persistent disorders of the heart and blood vessels, pathologies of neuropsychic activity.

In children, the passion for sweets leads to an increase in their activity up to the development of hyperactivity syndrome, neurosis, irritability.

Cellobiose disaccharide

Cellobiose is a disaccharide consisting of two glucose molecules. It is produced by plants and some bacterial cells. Cellobiosis has no biological value for humans: in the human body, this substance does not break down, but is a ballast compound. In plants, cellobiose performs a structural function, as it is part of the cellulose molecule.

Trehalose – mushroom sugar

Trehalose is made up of two glucose molecules. Contained in higher fungi (hence its second name – mycosis), algae, lichens, some worms and insects. It is believed that the accumulation of trehalose is one of the conditions for increased cell resistance to desiccation. It is not absorbed in the human body, however, a large intake of it into the blood can cause intoxication.

Disaccharides are widely distributed in nature – in the tissues and cells of plants, fungi, animals, bacteria. They are included in the structure of complex molecular complexes, and are also found in the free state. Some of them (lactose, sucrose) are an energy substrate for living organisms, others (cellobiose) perform a structural function.