Anti-caking agents are additive ingredients that serve to prevent lumps, commonly known as caking, from forming in food products and thereby protect or encourage features such as easy flow or desirable texture in products prone to caking, and to improve packaging and transportation of those products.1 Some products in which anti-caking agents may be found include non-dairy creamer and spices.
Since caking is generally caused by changes in crystalline structure that frequently are related to the presence of moisture; anti-caking agents typically work via moisture absorption or by coating particles to make them repel water.2 Silicon dioxide is one such anti-caking agent and works primarily by absorbing water. With this functional ingredient incorporated, foods can be stored for longer and meet expectations that they will remain dry and flow easily from containers during use.
Silicon dioxide is also known as silica, and has the chemical formula SiO2.3 This compound is naturally existing in nature, including in plants such as green leafy vegetables, beets, brown rice, and alfalfa, as well as geologically in quartz.3,4 Silicon dioxide is used in a dry, fluffy form to coat food item particles to prevent them from becoming moist and caking.5
There are many varieties of silicon dioxide, as its crystals can naturally occur in many formations. The particular variety used in food manufacturing is often fumed silica, also known as pyrogenic silica.3 It is formed by applying an oxygen-rich hydrogen flame to silicon tetrachloride; the resulting “smoke” is silicon dioxide. Another method of creating fumed silica is to vaporize quartz sand using an electric arc at 3000°C. Both of these preparations result in an amorphous silica in microscopic droplets that join into particles with low bulk density, giving fume silica a notably high surface area.3 This surface area allows the silicon dioxide to easily attract and absorb water, thus highly efficiently achieving its role as an anti-caking agent.
Silicon dioxide is deemed Generally Recognized as Safe (GRAS) by the United States Department of Agriculture (USDA), the Food and Drug Administration (FDA) requires that silicon dioxide make up no more than 2% of a food by weight.4 Mainly, this limitation is driven by a lack of research regarding the impact of consumption of higher quantities of silicon dioxide on the health of the human body. While the USDA and FDA allow this amount of silicon dioxide and consider it safe, the European Food Safety Authority (EFSA) has published concerns about whether it may actually be dangerous to health to include silicon dioxide in food items. The EFSA reports that there may be unsafe nanoparticles within silicon dioxide, and asserts that silicon dioxide has no established acceptable daily intake (ADI) that would lend guidance as to what amount would be safe to include in food items.6 Additionally, research from Purdue University has indicated that silicon dioxide may actually speed degradation of nutrients such as Vitamin C, rather than promote stabilization.7 Conversely, research has indicated that higher levels of silicon dioxide in drinking water may significantly decrease risk of dementia.3 Therefore, consider the market and potential consumer concerns when making decisions about whether to use silicon dioxide in food formulation, as it seems there is still ample room for significant research to be conducted around the topic of safety.
The market for fumed silica, the silicon dioxide variety used as an anti-caking agent, has grown and is expected to continue to grow, particularly considering that this ingredient has broad applications in industries such as cosmetics, pharmaceuticals, paints, inks, and adhesives, among many others. From 2021 to 2026, it is anticipated that the global fumed silica market will grow 5.1 percent.8
Recommended Reading
- Anticaking agent
- Humectants and Anticaking Agents
- Silicon dioxide
- Is Silicon Dioxide Safe?
- Sending Out an SAS: The Latest on Silicon Dioxide
- EFSA raises red flag for silicon dioxide safety over nanoparticles
- Anticaking ingredients may help to degrade, not stabilise, powdered nutrients, suggests research
- Fumed Silica Market
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