Activated carbon is also used to refine food. The origin of the industrial application of activated carbon even lies in this area. In 1794, charcoal was used for the first time in an English sugar refinery. Today, activated carbon serves a wide range of applications in the treatment of liquids in the food industry. Activated carbon usually has the task of removing color, other dissolved organic impurities as well as odors and flavors by adsorption. Powdered or granular activated carbon is usually used. But which carbon is suitable for which process? Gabriele Neuroth, who is responsible for application technology at Donau Carbon, often hears this question.
Powdered activated carbon – the flexible choice
"Our customers always like to use powdered carbon where they want to be flexible," says Neuroth. “You often have to treat raw materials with very different compositions. Let's take apple juice concentrate: depending on the texture, you want to correct the color or adjust the taste. Powdered activated carbon can be dosed accordingly precisely.” It is either stirred directly into the solution to be treated or dosed in the form of a 15% suspension. The activated carbon dosage is usually in the order of 0.1 to 1%, based on the amount of liquid to be treated. The exposure time of the activated carbon must be adjusted to the physical properties of the liquid to be treated, such as viscosity, temperature and pH value, as well as to the substances to be removed. A contact time of 15 to 30 minutes is usually completely sufficient. According to Neuroth, further reasons for opting for activated carbon in powder form are that you do not need your own filter system and the investment costs are comparatively low.
Granular activated carbon – the uncomplicated choice
Granular activated carbon, on the other hand, is suitable for companies with continuous production processes: “It is easy and safe to use: You fill in the granular activated carbon and then the system runs as a closed system and requires little maintenance. And because granulated activated carbon can in many cases be reactivated when it is exhausted, it is ultimately very cost-effective and environmentally friendly, even if the investment costs for a filter system are higher at the beginning.” This investment therefore pays off above all for regular processes of a certain type order of magnitude. The matching stainless steel filters can be ordered from Donau Carbon at the same time. "This eliminates the need for filtering, which is necessary with powdered carbon”.
Re-use or dispose?
Regenerating granular activated carbon sounds complicated, but in plain language it means nothing more than: "After a long period of use, it is washed out with hot water and then works perfectly again." If such regeneration is not sufficient, the activated carbon can be "reactivated” at higher temperature of 900 °C.
Powdered activated carbon, on the other hand, can be used several times within the production process: If it is already heavily "loaded", it can be used for coarse cleaning at an earlier stage of the same process. So their filtering effect is used to the last. And even after the end of its useful life, powdered activated carbon is still good for something, because, according to Neuroth: "You dry it, burn it and convert it into energy".
Possible areas of application for activated carbon in the food industry:
Removal of color
Starch, soup seasoning, beer, gelatin, coffee
Adjustment of taste
Vodka, wine
Adjustment of odour
Sugar, beverages, oil
Removal of unwanted substances
Edible oil, vitamins, fruit juices
Use as food coloring E 153
Sweets, liquorice, pasta, cosmetics
Further information and solutions for your application can be found at
www.donau-carbon.com