Tartaric acid: definition
The main component of grapes and tamarind, tartaric acid is a powerful antioxidant molecule with known lightening and exfoliating properties.
Together with glycolic, citric, and malic acid, tartaric acid is one of the most important alpha-hydroxy acids, the so-called fruit acids. The virtues of tartaric acid are exploited in different areas, ranging from cosmetics to cooking.
Therefore, the uses of tartaric acid are countless: let us now try to get to know this exceptional molecule more closely, studying it both from a chemical and an application point of view.
Curiosity
Tartaric acid was first isolated in the nineteenth century by the alchemist Gabir ibn Hayyan. The name "tartaric" derives from the compound from which it was isolated, the potassium tartar, known simply as tartar .
Chemical description
Chemically, tartaric acid is a crystalline dicarboxylic acid derived from succinic acid (molecular formula: C 4 H 6 O 6 ). It comes in the form of white powder, unalterable to air; it is very soluble in water and quite soluble also in glycerin, propyl alcohol and methyl alcohol. Tartaric acid is a chiral molecule: the two enantiomers are Levo-tartaric acid and dextro-tartaric acid.
Carried to high temperatures, tartaric acid decomposes, giving rise to an odor comparable to that of burnt sugar.
Toxicity
Pure and high dose tartaric acid is highly toxic: taking 7.5 g / kg of this molecule causes death from cardiovascular collapse and / or acute renal failure. If no action is taken promptly, the fatal outcome occurs in a period of time varying from 12 hours to 9 days after its administration. However, the chances of intoxication - at least for the involuntary one - are rather scarce: in fact, to kill a 80-pound man about 600 grams of tartaric acid are needed.
Taken within the recommended doses, tartaric acid turns out to be a completely harmless compound, since it is physiologically eliminated through the urine.
Tartaric acid in wine
Besides being one of the main components of grapes, tartaric acid is the most important acidity regulator in wine. Not surprisingly, the total acidity of a wine is measured starting from the quantity of tartaric acid dissolved in it (total acidity of the wine expressed in g / L of tartaric acid).
In wine, this fruit acid is very important and has many functions:
- Regulates the acidity of the wine: the acid pH of the wine acts as a protection against the attack of bacteria. It is possible to add tartaric acid to the wine to increase its acidity (ie reduce the pH)
- It gives a particular aroma to the wine
- It plays an important role in the coloring of wine
It is not uncommon for the wine's tartaric acid to crystallize, forming potassium bitartrate crystals, which are clearly visible in the cork stopper (the so-called wine diamonds ). Although harmless, these crystalline compounds - called "tartrates" - are often considered a sign of poor or bad wine.
Tartaric acid in cosmetics
In cosmetics, tartaric acid is used above all for its keratolytic, lightening and antioxidant capacities; not surprisingly, it is often the dominant ingredient in moisturizing, exfoliating, anti-stain and anti-aging creams.
Tartaric acid, in cosmetics, is indicated in the treatment of:
- Mature, arid and less elastic skin → formulated together with moisturizing substances (eg hyaluronic acid cream), tartaric acid effectively counteracts the dryness of skin that is no longer very young, restoring as much as possible their natural softness lost over the years
- Blackheads and acne → tartaric acid exerts excellent comedolytic activity, encouraging the emptying of cysts
- Dark spots on the skin → tartaric acid exfoliates the skin by removing superficial cells from the epidermis, while encouraging cell renewal. In this way, tartaric acid creams increase the brightness of the skin
Creams or other cosmetic products formulated with tartaric acid require constant application. For an optimal result, it is recommended to spread the product in the morning and in the evening, on clean and carefully dried skin. The massage is an integral part of the treatment: for this reason, it is important to massage gently, until the cream is completely absorbed. Continue the treatment for at least 4-6 weeks.
Other applications
Tartaric acid is also found in the culinary, medical and in the cleaning of some metals.
In the kitchen, this substance is used as an acidity corrector (E334), for the preparation of non-alcoholic and effervescent drinks, bakery products, jams, sweets, dairy products and powdered yeasts.
In medicine, tartaric acid can also be used as a mild saline purgative (Rochelle salt); moreover, it is indicated for the production of thirst-quenching digestive drinks.
Some derivatives of tartaric acid (eg cremortartaro) can be added to water to form a rather unusual solution, but extremely effective for cleaning coins and other materials composed of copper. Furthermore, tartaric acid can also be used in the photographic industry, in printing and development processes.
