The acid oxalic it's a antinutrient and it is found in many foods, it is better to take note of which ones contain more and, in doing so, we will realize that in most cases they are foods of plant origin. Why are we talking about anti - nutrients? Because when we eat something that contains this acid it it combines with some minerals preventing them from doing us any good. It combines with the iron and also with the magnesium but above all with calcium and form of oxalates. The name oxalic, for the curious, comes from the French "oxalique", which in turn is ancient Greek "oxos", vinegar. We find the same origin for the oxalide plants, dicotyledonous angiosperms both herbaceous and as shrubs which usually live in areas that enjoy a temperate climate.
Oxalic acid: where it is found
In foods such as kiwi, spinach, rhubarb, whole grains there are considerable quantities of oxalic acid, even in cabbage and in many other foods of vegetable origin, while there are few those of animal origin that contain values for which to ask the problem.
It doesn't mean that these foods should be banned from the diet because they have many others useful and interesting properties, the best thing to do is to alternate them with others that do not contain oxalic acid in order to rebalance the diet.
In plants this acid also acts as a defense system from burning but there are cases in itself such as that of fenestraria in which the molecule has been co-opted towards a very different use from defense.
The acid in crystalline form within its own tissues, it serves to build a sort of optical fibers that are used to transport light to underground photosynthetic sites. From this mechanism derives the lightening at the top of the leaves which gives the name to the plant itself.
Oxalic acid: what it is
This acid is a antinutrient which has a strong effect on our body when taken. It irritates the intestinal walls and can be fatal if ingested in high doses, the limit value is 375 mg per kilogram of body weight, meaning that a person weighing 65-70 kg can take about 25-28 grams per day. When we ingest oxalic acid it binds with iron, magnesium and calcium and prevents these salts from being absorbed by the intestine. They do not help much, therefore, in this sense, and if we exaggerate there may be health problems such as for example osteoporosis or anemia, or kidney stones, linked to the presence of calcium.
Oxalic acid: how to reduce it
Precisely so as not to eliminate these foods from our diet, let's find out some easy tricks to ensure that their content of oxalic acid be reduced, reducing the risk for us of incurring health problems.
Faced with a antinutrient we can act by opting for boiling or steaming, to limit the calcium oxalates contained in green leafy vegetables. In general, especially for those who follow one vegetarian or vegan diet, it is important not to overdo the intake of spinach and chard alternating these vegetables with other types of vegetables that do not contain as much oxalic acid but which have a lot of calcium such as turnips and broccoli, lettuce, rocket and radicchio.
To reduce the risk associated withoxalic acid we must also check that mineral water we drink because even in it there can be an exaggerated quantity of acid which leads in the long run to a negative accumulation.
Oxalic acid: how to get it
In other fields that are not food, we want this acid and we ask ourselves how to obtain it in a convenient and inexpensive way. At room temperature it is found in the form of white and odorless solid granules, or as transparent and colorless crystals with a monoclinic structure.
Oxalic acid: applications
What do we do withoxalic acid if we can't eat it? We exploit its acidity and oxidation by using it in formulations of whitening and anti-rust products, for the surface treatment of wooden products, for example.
Also online, on Amazon, you can buy this substance, in powder form. A 750 gram pack can cost around 13 euros. It is also found under the name of "Sorrel salt”And is recommended for lightening old, often blackened or dirty woods, or for treating exotic woods. This product also allows to deoxidize copper and metals and to clean the polyester hulls of boats.
In the tanning and textile industry, it is used as stabilizer of hydrogen cyanide, for the manufacture of inks and detergents, as a medium for the precipitation of rare earths and for the manufacture of rubber.
Oxalic acid: formula
The oxalic acid formula is H2C2O4, sometimes also referred to as (COOH) 2, to prepare it industrially, the sodium formate is heated to 400 ° C and sodium hydroxide and borax are added.
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