Dimethyl dicarbonate is a food additive that is used in fruit juices, iced teas, sports drinks and carbonated drinks as a preservative and sterilizer. In wine, it breaks down to methanol and carbon dioxide, which also occur naturally in wine.
It is used as a preservative to inactivate residual spoilage by microorganisms during the processing of beverages, i.e. it is added to products after they have been processed by other physical or chemical cleaning methods, already to fix the result and their residual sterilization from microorganisms.
Chemical structure
The food supplement has a broad antimicrobial activity. The food supplement is approved for use in the EU and Russia and is recognized as safe. In some other countries it is also allowed, but in more limited quantities.
Dimethyl dicarbonate is a colorless liquid with a distinct fruity odor. It has a melting point of 17°C and a boiling point of 172°C. It is soluble in water with decomposition, and miscible with toluene, it is also quite soluble in alcohols. Dimethyl dicarbonate has the molecular formula C4H6O5, molecular weight 134,09 g/mol.
Use in the food industry
Dimethyl dicarbonate is used in the food industry for additional microbial control in beverages during the final filling steps. It is added to beverages whose viable microbial load has been previously reduced by other technologies immediately prior to bottling, canning or other form of final packaging.
To ensure its safe use, the maximum amount of dimethyl carbonate that can be added to food is 250 ppm. Dimethyl dicarbonate exhibits its antimicrobial activity against such microorganisms: Saccharomyces, Zygosaccharomyces, Rhodotorula, Candida, Pichia, Endomyces and others.
Dimethyl dicarbonate is currently approved as a yeast inhibitor in a variety of beverages under normal bottling or canning conditions where the amount of viable yeast is up to 500 per milliliter (mL) or less.
After degradation to methanol and carbon dioxide, the antimicrobial effect is not maintained. The additive is intended for use as a microbiological agent control in the following beverages:
- in wine, alcoholized wine and low-alcohol wine;
- in ready-to-drink teas;
- in carbonated or non-carbonated water;
- in carbonated, diluted beverages containing juice, fruit aroma, or both together with a juice content not exceeding 50 percent.
In beverages, E242 is approved for use under normal conditions of bottling, canning, or other forms of final packaging where the viable microbial load is reduced to 500 microorganisms per milliliter or less first by other manufacturing methods such as heat treatment, filtration, or other techniques prior to the use of dimethyl dicarbonate.
In solution, the dimethyl dicarbonate rapidly and completely hydrolyzes and/or reacts with the various constituents of the processed beverages, and as a result of this reaction, the dimethyl dicarbonate does not remain in the processed beverage ready to drink.
Safety E242
Actually, dimethyl dicarbonate itself does not enter the human body, since it immediately breaks down in the food product, but some researchers suggest that its decay products may have a negative effect.
The risk associated with the use of dimethyl dicarbonate as a food additive is exposure to methanol (a product of its hydrolysis) and the main reaction products (DMC, MEC and MC), but their content in the final product is the same as in any juices and carbonated drinks, without addition of this substance, since they are natural components of fruit juices.
Also, exposure of dimethyl carbonate directly to human skin and mucous membranes can be very dangerous and cause severe irritation.
Irritating to eyes and respiratory system, if vapors are inhaled. Therefore, when working with this food additive in production, it is recommended to use protective equipment, such as masks and goggles.
There is information about the possible carcinogenic effect of one of the substances that is formed during the decomposition of dimethyl dicarbonate – ethyl carbamate.
Dimethyl dicarbonate has been evaluated by various international regulatory bodies and has concluded that this dietary supplement does not cause health and safety concerns when used in permitted food categories and at certain doses.
The safety of dimethyl dicarbonate was assessed by the USFDA in 1988 and approved for use in wines as a yeast inhibitor up to a concentration of 200 mg/l. The European Scientific Committee on Food (SCF, 1992) evaluated E242 in 1990 and concluded that it is suitable for cold sterilization of soft drinks and fruit juices at levels up to 250 mg/l.
In 2001, this Committee set an upper limit of 200 mg/l for the use of dimethyl dicarbonate in alcoholic beverages that already contain methanol (SCF, 2001). It was also evaluated in 1990 by the Joint FAO/WHO Expert Committee on Food (JECFA, 1991).
It is considered acceptable as a cold sterilizing agent for beverages when used in accordance with good manufacturing practice up to a maximum concentration of 250 mg/l.