Tannins, or tannic acid, are water-soluble polyphenols (complex natural organic compounds) found in many plant foods.
From French, the name is translated as "tanning of the skin", which determines one of the main abilities of the substance.
general characteristics
Tannins are a yellow-brown powder. This substance is often found in plants, mainly in roots, tree bark, leaves, and some fruits. High concentrations are found in oak bark.
Tannin solutions are acids with an astringent taste. In the food industry, it gives products a tart taste, a certain color and aroma. Tannic acid is used in winemaking and brewing. And thanks to its astringent properties, it has found application in medicine - for the treatment of tonsillitis, pharyngitis, skin rashes, hemorrhoids.
Water-soluble tanning agents with compounds form a dark blue or dark green solution. This property allows the use of tannins for the manufacture of ink. In light industry, it is used for the production of leather, dyeing fabrics.
Classification of tannins
Given the chemical properties, there are 2 groups of tannins: hydrolyzable (dissolve in water) and condensed.
Representatives of the first group after hydrolysis with acids or enzymes create gallic and ellagic acids. From a chemical point of view, they are esters of phenolic acid. Gallic - mainly found in rhubarb, cloves, and ellagic - in eucalyptus leaves and pomegranate bark.
Condensed tannins are resistant to hydrolysis and are produced from flavonoids. These substances are found in henna bark, male fern seeds, tea leaves, wild cherry bark.
Physiochemical properties
Creams based on tannins relieve swelling and itching, and tannin in powder form is used as a bath additive.
Properties of medical tannin:
- relieves itching;
- treats various kinds of inflammation;
- eliminates microbes that cause disease;
- prevents dehydration of the epidermis;
- fights viruses with eczema, herpes, chicken pox;
- heals postoperative wounds;
- used in urology, gynecology, proctology;
- effective for healing first-degree burns;
- an effective remedy for dermatoses in children.
Meanwhile, it is worth noting that not only a synthetic analogue of a substance is used as a medicine. Traditional medicine often resorts to the use of plants rich in tannic acid. For example, galangal (root) treats diarrhea, chestnut strengthens the walls of blood vessels, eucalyptus is an effective remedy for colds. In addition, acorns (used as a coffee substitute) and sumac (used as a spice in oriental cuisine) have a beneficial effect on the body. Most plants rich in tannins have similar positive effects on the body.
The "dark" side of tannins
Too active consumption of products containing tannins is fraught with not the most pleasant consequences. In particular, digestive disorders, liver or kidney dysfunction are possible. Under the influence of tannins, irritation of the intestinal walls is possible. An excess of tannic acid prevents the proper absorption of useful minerals, in particular iron, which is fraught with the development of anemia.
It is important to treat these substances with extreme caution to people whose body does not perceive tannins. Otherwise, allergies are possible with very serious consequences. It is also important for people with heart failure and unstable blood pressure to avoid tannin-containing foods. Excessive consumption of tannins can cause dyspepsia and impair appetite.
Products rich in tannins
Probably, if someone wanted to compile a complete list of products containing tannins, they would have to rewrite almost all representatives of the earth's flora, since almost all plants contain tannins in one or another concentration in their different parts. We will name only the most popular products in which the concentration of tannins is close to the maximum.
Drinks: tea, cocoa.
Berries: grapes (dark varieties), blackcurrant, dogwood, bird cherry, pomegranate.
Fruits: quince, persimmon.
Vegetables: rhubarb, red beans.
Nuts: walnuts, almonds.
Spices: cinnamon, cloves.
In addition, acorns, chestnuts, eucalyptus, galangal root and dark chocolate are powerful stores of tannins.
As a dietary supplement
In the food industry, tannins are known as additive E181 (stabilizer, emulsifier, dye) - a yellow-brown powder with an astringent aftertaste and a specific odor. The raw materials for E181 are extracts of plants of the genus sumac and galls.
The substance earned its popularity in the food industry due to its ability to impart an astringent aftertaste. In addition, it is actively used due to the ability to protect the peel of vegetables and fruits from rotting and drying out. If we talk about the effect on taste buds, then this substance is a bit like glutamic acid, and gives food a specific flavor of savory. Also, tannic acid in the form of E181 is used as a clarifier for beer, wine and other products.
If you are a wine lover, you have probably heard of the so-called tannin drinks. Although it is possible, for many it remains a mystery what it is - the concentration of tannin in wine, and what is the role of tannins in winemaking. Now let's try to clarify what is in wine and why some of these drinks cause severe headaches.
The effect of tannins is easy to recognize even after the first sip of wine - it is a characteristic dry mouth and astringent aftertaste. Depending on the intensity of manifestation of these effects, we can talk about the level of concentration of tannins in the drink.
Tannic acid enters the composition of wine in two ways: from certain grape varieties and from wood. Grape tannin is found mainly in the skin, seeds and stems of the berry. In red wines, its amount is much higher. In addition, the concentration of tannins depends on the grape variety.
Another route for tannins into a glass of wine is through wood. Or rather, the barrel in which the drink was stored. Oak vessels are the most popular in winemaking, as they give the drink a specific flavor. To better understand what the taste of tannin is, ordinary tea will help. It is enough to brew a strong drink (without sweeteners) and insist it a little longer than usual. The very first sip of such tea will immediately make it clear everything about the taste of tannin. Light bitterness on the middle part of the tongue and tart dryness on its tip - this is tannin in action. In fact, black tea is an aqueous solution of tannin.
The concentration of tannic acid in wine depends not only on which grape varieties the drink is made from, but also on how long the skin, seeds and stems have been in contact with the juice of the berry. In the production of red wines for a deeper color, the berry skins are aged in the juice for a longer time. This explains why significantly more tannins are found in this type of wine. But this does not mean that white varieties are devoid of tannins. Tannic acid gets into them, first of all, from oak barrels, and similarly gives white wines dryness, astringency, bitterness.
But tannins in winemaking are used not only to improve taste. In this area, tannins, among other things, play the role of natural ones, which contribute to the long storage of grape drinks. Meanwhile, over the years, the concentration of tannic acid in wines is lost, which affects the taste of the drink, and it becomes softer.
But wine tannins also have their downsides. Some people react to tannic acid with severe headaches. This explains the migraines that some wine lovers suffer from, even after a very small portion of the drink. Therefore, it is better for people who are sensitive to tannin to enjoy white varieties so as not to suffer the next day.
Tannin in tea
But wine is not the only drink that contains tannins. In tea, the concentration of this substance is also quite high. Tannic acid is present in all types of drink, but, as in the case of grapes, some varieties contain more of it.
First of all, this applies to green varieties. Some of them contain over 30% tannin. But it is worth noting that the concentration of tannic acid in tea plants depends on several factors. Firstly, it is important in what climatic and natural conditions the product was grown. It is believed that in Ceylon, Indian and Javanese teas, the concentration of tannins is higher, hence their amazing tart taste. In addition, in the leaves collected in July or August, the substance is much greater than in the drinks "born" in May or September. Secondly, the age of the plant also matters: the maximum amount of tannins is found not in young shoots, but in older leaves.
By the way, the tannic acid contained in tea is somewhat different in chemical composition from its counterpart from other products and the synthetic "brother". Tea tannins resemble vitamin P and have a strengthening effect on blood vessels.
Tanning agents and industry
If we recall that the French name for tannins is translated as "tanning of the skin", it becomes clear in which industry this substance is most often used. Sheepskin coats and furs, in which we all love to wrap ourselves up in cold winters, are the result of the use of tannins. In addition, the production of various types of inks, humanity is also obliged to tanning agents. And the mordant of textile fibers without tannins is also hard to imagine.
Interaction with other substances
Scientists continue to study the properties of tannin, since there is still a lot of unknown in the biography of this substance. In particular, scientists analyze how tannic acid affects the body, and especially how it “gets along” with other useful elements.
At present, for example, the combination of tannin and caffeine (which is present in tea) is perhaps the most studied. In this unusual "cocktail" of substances, scientists were primarily interested in why tea, which contains a rather high concentration of caffeine, has a relaxing effect on the body. It turned out that all this is the merit of tannin, which, in combination with caffeine, does not act on the body invigoratingly (like coffee), but rather as a relaxation agent and causes a restful sleep. But in addition to affecting the nervous system, tannins act as protectors for liver cells. In particular, the body needs the protective effect of tannic acid after alcohol abuse.
If we talk about the combination of tannin with other medicines, then it interacts well with antimicrobials and antibiotics.
Tannin does not belong to the substances, the beneficial properties of which are known to almost everyone. Moreover, many do not even know about the existence of tannic acid and its role for humans. Meanwhile, tannins do not just exist, but greatly facilitate our lives. And if you have read this text to the end, then now you know almost everything about the role of tanning agents.
Sources
- Kretovich V.L. Biochemistry of plants: Textbook for biol. faculties of universities. - M .: Higher. school - 1980 - S. 307 - 308.
- Kurkin V.A. Pharmacognosy: A textbook for students. pharmaceutical universities / V.A. Kurkin. - Samara: LLC "Ofort", GOUVPO "SamGMU". - 2004. - S. 867 - 876.
Tea. This drink has been known to mankind for more than five thousand years. It was drunk by the Chinese emperors. The Queen of England drinks it. We are also fans of this wonderful drink. Let's take a look at its composition.
The first place in it is occupied by natural aromatic compositions. The second place is occupied by tannin. The chemical composition of aromatic compositions depends on the place of growth of tea and the conditions of its collection and preparation.
As for tannin, to which this article is devoted, its content depends not so much on weather and climatic characteristics, but on the age of the tea leaf itself. The older the leaf, the more tannin it contains.
Foods rich in tannin:
General characteristics of tannins
What are tannins? Tannin, or gallodubic acid, is an astringent. The name comes from the French word "tanner", which in translation into Russian means skin tanning.
Tannins are found in tea and bird cherry, acorns and galangal rhizomes. It is thanks to tannins that wines made from dark grapes are very popular.
In addition, tannin is widely used as a tanning agent in the manufacture of leather goods. It is also used in the pharmaceutical industry in the manufacture of astringent anti-inflammatory drugs.
Daily requirement for tannin
Due to the fact that tannin performs a tanning function in our body, there is no data on its daily intake. It should be noted that the allowable amount of tannin consumed (as part of related compounds) depends on the individual characteristics of the organism.
The need for tannin increases:
With diseases of the gastrointestinal tract. Also, a solution of tannin in glycerin can be used to lubricate weeping wounds and ulcers for their fastest healing. In addition, tannin is used for mild diabetes and in case of detection of pathogenic bacteria and viruses.
The need for tannin is reduced:
- in case of individual intolerance to tannin;
- with increased blood clotting.
Useful properties of tannin and its effect on the body
- stimulates the speedy scarring of stomach ulcers;
- has a detoxifying component;
- capable of neutralizing pathogens;
- used for indigestion.
Useful properties of some products containing tannins
Acorns are used as a substitute for coffee, flour, used as a cure for some serious diseases. In addition, in animal husbandry, acorns are used to feed pigs.
The root of galangal (Potentilla erectus) has proven itself well for diarrhea. Eucalyptus is used in folk medicine and herbal medicine, as a deodorant, and as a remedy for colds.
Chestnut has a beneficial effect on the walls of blood vessels.
Interaction with other elements
Tannins interact well with proteins and all kinds of other biopolymers.
Signs of excess and lack of tannin in the body
Due to the fact that tannins do not belong to the group of coordinating compounds, no signs of excess, as well as deficiency, were found. The use of tannin is associated, rather, with the episodic needs of the body for this substance.
Tannins for beauty and health
Since tannin has the ability to deactivate a huge amount of poisons of biological origin, the use of products containing it leads to a good mood and health. And, therefore, everyone who wants to have good health, energy and beautiful skin should definitely use tannin-containing products. After all, health and beauty is so important!
And in conclusion, I would like to recall all the advantages of tannin-containing products. Tannin has the ability to deactivate poisons of biological origin, as a result of which harmful compounds lose their teratogenic power. Tannin gives a special astringent taste to products containing it. In addition to internal use, tannin can also be used in the treatment of open wounds and ulcers (in combination with glycerin). All tannin-containing products have healing power.
Gross formula
C 76 H 52 O 46Pharmacological group of the substance Tannin
Nosological classification (ICD-10)
CAS code
1401-55-4Characteristics of the substance Tannin
Obtained from ink nuts (Gallae turcicae), growths on young shoots of Asia Minor oak or domestic plants - sumac (Rhus coriaria L.) and skumpii (Cotinus coggygria Scop., Rhus cotinus L.), family sumac (Anacardiaceae).
Light yellow or brownish-yellow amorphous powder or flakes, or porous mass of astringent taste, with a slight peculiar smell. Partially darkens in air and under artificial lighting, at 210-215 °C it decomposes into pyrogallol and carbon dioxide. Forms insoluble compounds with albumin, starch, gelatin, most alkali and metal salts. Easily soluble in water (1 g in 0.35 ml), soluble in warm glycerin (1 g in 1 ml), freely soluble in alcohol and acetone. Practically insoluble in benzene, chloroform, ether, petroleum ether, carbon disulfide, carbon tetrachloride.
Pharmacology
pharmachologic effect- detoxifying, astringent, complexing, anti-inflammatory local.The astringent effect is due to the ability to cause precipitation of proteins with the formation of dense albuminates. When applied to the mucous membranes or wound surface, partial coagulation of the proteins contained in the mucus or wound exudate occurs, which leads to the formation of a dense protein film that protects the underlying tissues and the sensitive nerve endings located in them from irritation. It causes local vasoconstriction, reduces pain and helps to reduce the inflammatory response.
Application of Tannin
Inflammatory processes in the mouth, nose, pharynx, larynx; burns, ulcers, cracks, bedsores; intoxication with alkaloids and salts of heavy metals.
