Contenido

Se emplea sobre todo en el curtido del cuero, en grandes cantidades convierte las células de la piel en un material muy parecido al corcho. Otro empleo en la industria textil es como mordiente para fijar los colores en las fibras.

Uses as medicine

Along with magnesium and sometimes activated charcoal, tannic acid was once used as a treatment for many toxic substances, such as strychnine, mushroom, and ptomaine poisonings in the late 19th and early 19th centuries.[14]

The introduction of tannic acid treatment of severe burns in the 1920s significantly reduced mortality rates. During the First World War, tannic acid dressings were prescribed to treat "burns, whether caused by incendiary bombs, mustard gas or lewisite." After the war this use was abandoned due to the development of more modern treatment regimens.

Also, internally it is used as an active astringent in diarrhea. As intestinal astringents, tannic drugs or tannin derivatives are preferable, as they are slowly decomposed and can exert their action throughout the digestive tract. It is also used in cholera, night sweats of tuberculosis patients, in acute articular rheumatism, in general septic infections as a result of tonsillitis, in chronic bladder catarrh, and in renal and uterine hemorrhages. In dermatology it is used as an astringent and anti-inflammatory; in skin processes such as oozing ulcerations, bedsores, skin cracks, etc., and for the treatment of burns. In the form of suppositories it has been used in the treatment of hemorrhoids.

It is a magnificent antidote to alkaloids and some metallic salts.

During pregnancy, tannic acid should not be used to combat hemorrhoids, as its absorption in the anorectal area can cause fetal toxicity.

Uses in the treatment of wood and fabrics

It is also used in the treatment of wood for exteriors to preserve it from cold, heat and rain.

Wood containing tannic acid, after some time, can detach and discolor the underlying floor. Laminate flooring with tannic acid should never be installed on a surface susceptible to staining.

In laboratory staining techniques, it is used during staining of prokaryotic flagella before performing the actual staining with rosaniline and after fixing with formaldehyde due to the fragility of the flagellum.

Tannins are a basic ingredient in chemical wood staining, and are already present in woods such as oak, walnut and mahogany. Tannic acid can be applied to low-tannin woods to react with chemical dyes that require a tannin content. The presence of tannins in the bark of the redwood (Sequoia) is a strong natural defense against forest fires, decay and infestation by certain insects such as termites. It is found in the seeds, bark, cones and heartwood.

Tannic acid is a common mordant used in the dyeing process of cellulose fibers such as cotton, often combined with alum and/or iron. The tannic mordant should be done first, since metallic mordants combine well with the fiber-tannin complex. However, this use has lost much interest.

Similarly, tannic acid can also be used as a post-treatment to improve the wash fastness properties of acid-dyed polyamide. It is also an alternative to fluorocarbon post-treatments to impart stain-resistant properties to polyamide yarns or carpets. However, due to economic considerations, currently the only widespread use as a textile auxiliary is the use as an agent to improve chlorine fastness, that is, the resistance against bleaching of the dye due to cleaning with hypochlorite solutions in high-end carpets and swimsuits based on polyamide 6,6. However, it is used in relatively small quantities for the activation of upholstery flocking; This serves as an antistatic treatment.

Use in the treatment of ferrous metal objects

Tannic acid is used in the preservation of ferrous (iron-based) metal objects to passivate and inhibit corrosion. Tannic acid reacts with corrosion products to form a more stable compound, thus preventing further corrosion from occurring. After treatment, the tannic acid residue is usually left on the object so that if moisture reaches the surface, the tannic acid will rehydrate and prevent or slow down any corrosion. Tannic acid treatment for conservation is very effective and widely used, but it has a significant visual effect on the object, blackening corrosion products and staining the exposed metal dark blue. It should also be used with care on objects with copper alloy components, as tannic acid can have a slight etching effect on these metals.

Tannic acid is also found in commercial corrosion treatments for iron and steel.

Tannic acid could cause potential health hazards such as damage to the eyes, skin, respiratory tract, and gastrointestinal tract. May cause irritation, redness, pain, blurred vision, and possible eye damage. When tannic acid is absorbed through the skin in harmful amounts, it can cause irritation, redness, and pain. Nausea, vomiting, and diarrhea are symptoms of tannic acid ingestion, and prolonged exposure can cause liver damage. By inhalation, tannic acid can cause respiratory tract irritation.[17]​.

In many parts of the world its use in food is allowed. In the United States, the Food and Drug Administration (FDA) recognizes that tannic acid is "generally recognized as safe" for use in baked goods and confectionery products, alcoholic and non-alcoholic beverages, frozen dairy products, soft and hard candies, meat products and rendered animal fats with maximum limits established in legislation.[18]​.

According to Regulation (EC) No 1333/2008 on food additives of the European Union,[19]​ tannic acid cannot be considered a food additive and is therefore not on the positive list of authorized additives and does not have an E number. The number E181 is sometimes incorrectly used to refer to tannic acid; In fact, it is the International Food Additive Numbering System number assigned to tannins according to the FAO-WHO Codex Alimentarius system.

Tannic acid is a specific form of tannin, a type of polyphenol. Its weak acidity (pKa around 6) is due to the numerous phenolic groups in its structure. The chemical formula of commercial tannic acid is often given as CHO, which corresponds to decagalloylglucose, but it is actually a mixture of polygalloylglucoses or polygalloylquinic acid esters, with a number of molecules from 2 to 12, depending on the plant source used to extract the tannic acid. Commercial tannic acid is usually extracted from any of the following parts of the plant: Tara pods (Caesalpinia spinosa), gallnuts of Rhus semialata") or Quercus infectoria or leaves of Sicilian sumac (Rhus coriaria).

According to the definitions given in external references such as the International Pharmacopoeia, the Codex Alimantarius and the FAO-WHO monograph on tannic acid, only tannins obtained from the mentioned plants can be considered tannic acid. Chestnut or oak wood extracts are also sometimes described as tannic acid, but this is an incorrect use of the term. It is a yellow to light brown amorphous powder.

Although tannic acid is a specific type of tannin (plant polyphenol), the two terms are sometimes used interchangeably (incorrectly). Long-standing misuse of the terms and their inclusion in academic articles has compounded the confusion. This is especially widespread in relation to green tea and black tea, as both contain many different types of tannins and not exclusively tannic acid.[20]​.

Tannic acid is not an appropriate standard for any type of tannin analysis due to its poorly defined composition.

The skin color of Crocodilia (crocodiles and alligators) depends greatly on the quality of the water. Algae-laden waters produce greener skin, while the tannic acid present in the water from the decomposition of the leaves of hanging trees (which produces some types of blackwater rivers) usually produces darker skin in these animals.[21]​.

Contenido

Se emplea sobre todo en el curtido del cuero, en grandes cantidades convierte las células de la piel en un material muy parecido al corcho. Otro empleo en la industria textil es como mordiente para fijar los colores en las fibras.

Uses as medicine

Along with magnesium and sometimes activated charcoal, tannic acid was once used as a treatment for many toxic substances, such as strychnine, mushroom, and ptomaine poisonings in the late 19th and early 19th centuries.[14]

The introduction of tannic acid treatment of severe burns in the 1920s significantly reduced mortality rates. During the First World War, tannic acid dressings were prescribed to treat "burns, whether caused by incendiary bombs, mustard gas or lewisite." After the war this use was abandoned due to the development of more modern treatment regimens.

Also, internally it is used as an active astringent in diarrhea. As intestinal astringents, tannic drugs or tannin derivatives are preferable, as they are slowly decomposed and can exert their action throughout the digestive tract. It is also used in cholera, night sweats of tuberculosis patients, in acute articular rheumatism, in general septic infections as a result of tonsillitis, in chronic bladder catarrh, and in renal and uterine hemorrhages. In dermatology it is used as an astringent and anti-inflammatory; in skin processes such as oozing ulcerations, bedsores, skin cracks, etc., and for the treatment of burns. In the form of suppositories it has been used in the treatment of hemorrhoids.

It is a magnificent antidote to alkaloids and some metallic salts.

During pregnancy, tannic acid should not be used to combat hemorrhoids, as its absorption in the anorectal area can cause fetal toxicity.

Uses in the treatment of wood and fabrics

It is also used in the treatment of wood for exteriors to preserve it from cold, heat and rain.

Wood containing tannic acid, after some time, can detach and discolor the underlying floor. Laminate flooring with tannic acid should never be installed on a surface susceptible to staining.

In laboratory staining techniques, it is used during staining of prokaryotic flagella before performing the actual staining with rosaniline and after fixing with formaldehyde due to the fragility of the flagellum.

Tannins are a basic ingredient in chemical wood staining, and are already present in woods such as oak, walnut and mahogany. Tannic acid can be applied to low-tannin woods to react with chemical dyes that require a tannin content. The presence of tannins in the bark of the redwood (Sequoia) is a strong natural defense against forest fires, decay and infestation by certain insects such as termites. It is found in the seeds, bark, cones and heartwood.

Tannic acid is a common mordant used in the dyeing process of cellulose fibers such as cotton, often combined with alum and/or iron. The tannic mordant should be done first, since metallic mordants combine well with the fiber-tannin complex. However, this use has lost much interest.

Similarly, tannic acid can also be used as a post-treatment to improve the wash fastness properties of acid-dyed polyamide. It is also an alternative to fluorocarbon post-treatments to impart stain-resistant properties to polyamide yarns or carpets. However, due to economic considerations, currently the only widespread use as a textile auxiliary is the use as an agent to improve chlorine fastness, that is, the resistance against bleaching of the dye due to cleaning with hypochlorite solutions in high-end carpets and swimsuits based on polyamide 6,6. However, it is used in relatively small quantities for the activation of upholstery flocking; This serves as an antistatic treatment.

Use in the treatment of ferrous metal objects

Tannic acid is used in the preservation of ferrous (iron-based) metal objects to passivate and inhibit corrosion. Tannic acid reacts with corrosion products to form a more stable compound, thus preventing further corrosion from occurring. After treatment, the tannic acid residue is usually left on the object so that if moisture reaches the surface, the tannic acid will rehydrate and prevent or slow down any corrosion. Tannic acid treatment for conservation is very effective and widely used, but it has a significant visual effect on the object, blackening corrosion products and staining the exposed metal dark blue. It should also be used with care on objects with copper alloy components, as tannic acid can have a slight etching effect on these metals.

Tannic acid is also found in commercial corrosion treatments for iron and steel.

Tannic acid could cause potential health hazards such as damage to the eyes, skin, respiratory tract, and gastrointestinal tract. May cause irritation, redness, pain, blurred vision, and possible eye damage. When tannic acid is absorbed through the skin in harmful amounts, it can cause irritation, redness, and pain. Nausea, vomiting, and diarrhea are symptoms of tannic acid ingestion, and prolonged exposure can cause liver damage. By inhalation, tannic acid can cause respiratory tract irritation.[17]​.

In many parts of the world its use in food is allowed. In the United States, the Food and Drug Administration (FDA) recognizes that tannic acid is "generally recognized as safe" for use in baked goods and confectionery products, alcoholic and non-alcoholic beverages, frozen dairy products, soft and hard candies, meat products and rendered animal fats with maximum limits established in legislation.[18]​.

According to Regulation (EC) No 1333/2008 on food additives of the European Union,[19]​ tannic acid cannot be considered a food additive and is therefore not on the positive list of authorized additives and does not have an E number. The number E181 is sometimes incorrectly used to refer to tannic acid; In fact, it is the International Food Additive Numbering System number assigned to tannins according to the FAO-WHO Codex Alimentarius system.

Tannic acid is a specific form of tannin, a type of polyphenol. Its weak acidity (pKa around 6) is due to the numerous phenolic groups in its structure. The chemical formula of commercial tannic acid is often given as CHO, which corresponds to decagalloylglucose, but it is actually a mixture of polygalloylglucoses or polygalloylquinic acid esters, with a number of molecules from 2 to 12, depending on the plant source used to extract the tannic acid. Commercial tannic acid is usually extracted from any of the following parts of the plant: Tara pods (Caesalpinia spinosa), gallnuts of Rhus semialata") or Quercus infectoria or leaves of Sicilian sumac (Rhus coriaria).

According to the definitions given in external references such as the International Pharmacopoeia, the Codex Alimantarius and the FAO-WHO monograph on tannic acid, only tannins obtained from the mentioned plants can be considered tannic acid. Chestnut or oak wood extracts are also sometimes described as tannic acid, but this is an incorrect use of the term. It is a yellow to light brown amorphous powder.

Although tannic acid is a specific type of tannin (plant polyphenol), the two terms are sometimes used interchangeably (incorrectly). Long-standing misuse of the terms and their inclusion in academic articles has compounded the confusion. This is especially widespread in relation to green tea and black tea, as both contain many different types of tannins and not exclusively tannic acid.[20]​.

Tannic acid is not an appropriate standard for any type of tannin analysis due to its poorly defined composition.

The skin color of Crocodilia (crocodiles and alligators) depends greatly on the quality of the water. Algae-laden waters produce greener skin, while the tannic acid present in the water from the decomposition of the leaves of hanging trees (which produces some types of blackwater rivers) usually produces darker skin in these animals.[21]​.