Processed foods often contain ingredients that are mixed as powders. Anti-caking agents are added to allow them to flow and mix evenly during the food production process. They rarely have nutritional value and only a small proportion of the additives find their way into the food.
Some anti-caking agents may be found in foods. For example, magnesium carbonate is used in table salt to improve its flow during manufacture. It is left in the salt so that it flows well when being sprinkled onto food.
Examples of foods that contain anti-caking agents include:
What would happen without anti-caking agents?
Powders can form clumps because the particles become sticky when they absorb water. Lumpy powders do not flow evenly. Some powders, such as grated cheese for pizza toppings, can stick together and this again prevents them from being spread evenly. Anti-caking agents modify the contact between the powder's particles and are added to prevent these problems.
Without anti-caking agents, vending machine powders such as coffee or chocolate would not flow regularly. They could block the various tubes in the vending machine and the taste of the drinks would not be consistent enough. Powdered milk can clump together during processing, packing and storage. Sugar absorbs water and incorporating a free-flow aid before grinding prevents it sticking to the processing equipment.
The range of anti-caking agents
One of the most important anti-caking agents is silicon dioxide (E551). It is manufactured to have physical properties that are tailored to meet the food producer's specific requirements. Other manufactured anti-caking agents include: calcium silicate (E552), sodium aluminosilicate (E554) and dicalcium phosphate (E341). Natural products such as talc, kaolin, potato starch and microcrystalline cellulose (E460) are also used.