Sulfur dioxide or sulfur dioxide is a colorless gas with an irritating odor (reminiscent of "rotten eggs") and extremely soluble in water, which is produced by burning sulfur when it comes into contact with air.
It can be used as such or in liquid form, while sulphites appear as powders.
In ancient times sulfur dioxide was used to disinfect fermentation vats, but it is only since 1920 that sulphites are used with some frequency during the preparation of food and drinks. Sulfur dioxide was and is used as an antimicrobial, antifungal, inhibitor of the enzymatic and non-browning process, antioxidant and as a whitener of sugar and starch.
Due to its antimicrobial properties, sulfur dioxide is used as an additive in sugar decolorizing processes, and in the preservation of wine must, beer, fruit juices and sausages; on the label, it is identified by the abbreviation E 220. Sulfur dioxide can have different functions and applications:
- Most of the sulfur dioxide is transformed, through an oxidative process, into trioxide (SO 3 ); later, the latter is used to form sulfuric acid.
- A small amount of sulfur dioxide is used to produce sulphites used to preserve food and wine (in wine they have an antioxidant role, reduce the growth of bacteria and yeasts, stop possible fermentations, and facilitate the extraction of color and taste from the marc to the wine itself, by law the limit of sulphites is 200 mg / l);
- It is used for maintaining the color of dried fruit and grapes;
- It is also used for the production of organic sulphonates and carbon disulphide;
- It is used as a bleaching agent in the paper, textile and sugar industries (refined sugar can only contain up to 15 mg of sulfur dioxide per kg);
- It is used as a reducing agent in the production of tannins (they are common polyphenolic compounds in plants);
- It is used in the food industry and in the cold industry as a pesticide and antibacterial.
Sulfur dioxide can be used in: fish preserves, pickles, in oil or in brine, jams, frozen crustaceans, dried or candied fruit, non-alcoholic drinks based on fruit juices, wines, vinegar and dried mushrooms. It is therefore a very frequent additive in various products.
It is essential to stress that the quantity present in a single food is not harmful, but the sum of the various quantities contained in the different products taken during the whole day. They must pay close attention to the consumption of foods containing this preservative, especially asthmatic people, especially if they are treated with cortisone, because they are very sensitive to sulphates and can present more or less serious respiratory difficulties.
In humans and animals, sulfur dioxide is very irritating to the eyes, mucous membranes and above all to the respiratory tract: even minimal exposure can lead to acute pharyngitis, loss of smell, loss of taste and pulmonary edema (if inhaled).
It can also cause strong acidity in the urine, fatigue, headache, nervous disorders, allergic reactions, dysentery, etc.
Besides the rest, from a nutritional point of view it seems that sulfur dioxide also hinders the assimilation of vitamin B1 and B12, reducing the nutritional value of the foods that contain them.
The problems associated with its use are often overcome by using its salts (sulphites), because they are easier to use although they have the same side effects (since they release sulfur dioxide).
- E221 SODIUM SULPHITE
- E222 SODIUM SULPHITE ACID or SODIUM BISOLFITE
- E223 SODIUM METABISOLFITO
- E224 POTASSIUM METABISOLFITO
- E225 CALCIUM DISOLFITO
- E226 CALCIO SULPHITE
- E227 SOCCER BISOLFITO OR CALCIUM SULPHITE ACID