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 acids, tartaric acid is one of the most important alpha-hydroxy acids, the so-called fruit acids . The virtues of tartaric acid are exploited in various fields, ranging from cosmetics to cooking. While in cosmetics tartaric acid is often the undisputed protagonist of exfoliating peels and depigmenting creams, in the kitchen it is indicated both as an acidity regulator and as a leavening agent (added to sodium bicarbonate ). But that’s not all: phytotherapy and medicine have also been able to grasp the surprising properties of tartaric acid. In the phytotherapeutic field, the molecule is added to other active ingredients or natural extracts as a precious antioxidant, while in the medicinal field tartaric acid can be added (once again) to sodium bicarbonate to prepare effervescent digestives .
Therefore, the uses of tartaric acid are innumerable: now let’s try to get to know this exceptional molecule more closely, studying it from both a chemical and an applicative point of view.
Tartaric acid was isolated for the first time in the 19th century by the alchemist Gabir ibn Hayyan. The name “tartaric” is derived from the compound from which it was isolated, the calculus of potassium , simply known as tartar .
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 a white powder, unalterable in the 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.
Taken to high temperatures, tartaric acid decomposes, giving rise to an odor comparable to that of burnt sugar .
Tartaric acid pure and in high doses is highly toxic: the intake of 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 ranging from 12 hours to 9 days after its administration . In any case, the chances of intoxication – at least for the involuntary one – are quite low: in fact, about 600 grams of tartaric acid are needed to kill an 80-kilo man.
Taken within the recommended dose, tartaric acid turns out to be a completely harmless compound, as it is physiologically eliminated in the urine .
Tartaric acid in wine
In addition to being one of the main components of grapes, tartaric acid is the most important acidity regulator of wine . Not surprisingly, the total acidity of a wine is measured precisely 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 wine to increase its acidity (i.e. 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 tartaric acid in wine to crystallize, forming potassium bitartrate crystals, clearly visible in the cork (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 abilities ; 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, dry and not very elastic skins → formulated together with moisturizing substances (eg hyaluronic acid cream), tartaric acid effectively counteracts the dry skin of skin that is no longer very young, restoring as much as possible their natural softness lost over the years
- Blackheadsand acne → tartaric acid exerts an excellent comedolytic activity, encouraging the emptying of cysts
- Dark spotson the skin → tartaric acid exfoliates the skin by removing the surface 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 a period of at least 4-6 weeks.
Tartaric acid also finds space in the culinary and medical fields and in the cleaning of some metals.
In the kitchen, this substance is used as an acidity regulator (E334), for the preparation of non-alcoholic and sparkling drinks, bakery products, jams, sweets, dairy products and baking powder .
In medicine, tartaric acid can also be used as a mild saline purgative (Rochelle salt); moreover, it is suitable for the production of thirst-quenching-digestive drinks. Some derivatives of tartaric acid (eg cream of tartar
) can be added to water to form a rather unusual but extremely effective solution 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.