Tartaric Acid

Tartaric Acid is an alpha-hydroxy carboxylic acid. Its chemical formula is C₄H₆O₆. It is an organic acid and is naturally found in various vegetables and fruits such as grapes, bananas, tamarinds, etc. It is also a by-product of winemaking.

It also goes by the names 2, 3-dihydroxysuccinic acid, 2, 3-dihydroxybutanedioic acid, and racemic acid. It is a diprotic acid with a characteristic sharp tart taste. Its molecular weight or molar mass is 150.087 g/mol. Further, it is a dihydroxy derivative of dicarboxylic acid and its salts are called tartrates.

Origin of Tartaric Acid

It is a natural acid, which is commonly found in nature as 2 stereoisomers. For the first time, it was isolated from potassium tartrate by Jabir lbn Hayyan in Iraq in the 7^th century. Its chirality was discovered by Jean Baptiste Biot who found that it could rotate polarized light. Later, Louis Pasteur studied the shapes of tartaric acid crystals, which he found asymmetric.

Commercial Production of Tartaric Acid

It can be produced by both natural and synthetic methods. In the natural method, the reddish precipitated salt from argol (sediment in wine vats) is used. So, it is produced commercially from the waste products left behind during making of wine. In synthetic way, it is prepared from maleic anhydride.

Characteristics of Tartaric Acid

It is available in the form of colorless to white translucent fine crystals or granular crystalline powder. It is a solid material at room temperature owing to its high melting point: 170 degrees Celsius. And, its boiling point is 275 degrees Celsius.

It is expensive than many acidulants such as citric acid and malic acid. All types of tartaric acid are soluble in water. When it reacts with bases, it forms salts. For example, cream of tartar (potassium hydrogen tartrate) and Rochelle salt (potassium sodium tartrate). When dissolved in water, it forms insoluble calcium tartrate precipitates.

Tartaric Acid Structure

Its molecule has 4 carbon atoms, 6 hydrogen atoms, and 6 oxygen atoms. It contains two hydroxy (OH) groups along with two carboxylic acid (COOH) groups. Further, it is a chiral molecule, which shows stereoisomerism: D-tartaric acid, L-tartaric acid, and meso-tartaric acid.

Properties of Tartaric Acid

• Its density at 20 degrees Celsius is 1.76 Kg/m³
• Its solubility in water at 25 degrees Celsius is 156%.
• It has a bitter tart taste.
• It is soluble in water.
• In solid-state, it appears as small white crystals.

Uses of Tartaric Acid

• It is added in oral medications to improve their taste.
• It is used to chelate metal ions.
• It acts as a leavening agent in baking soda.
• It is also used in the preparation of wines.
• It is used to give a sour taste to food items.
• It is used to induce vomiting.
• It is used to make silver mirrors and in the dyeing of textiles.
• It is used as a stabilizer in food and candies.
• It is required in the tanning of leather.
• It is also applied on gloves as a dusting powder.
• It aids digestion by improving absorption of food in the intestines.

Health Hazards

If it is inhaled, it is absorbed into the body and causes burning sensation and difficulty in breathing. Further, it can cause redness and irritation when comes in contact with skin and can also cause pain in the eyes.

It is a muscle toxin, which prevents the production of malic acid and may cause death or paralysis in high doses. However, in low doses in food products, it is safe for human consumption.