Silicon dioxide, also known as synthetic amorphous silica (SAS), is widely used in food products as a thickener, anticaking agent, and carrier for fragrances and flavors.
Derived from naturally occurring quartz, silicon is the most abundant mineral in the earth’s crust. It’s also naturally found in water and plant-based foods, especially cereals like oats, barley and rice.
Silicon should not be confused with silicone, a plastic material that contains silicon and other chemicals used to make breast implants, medical tubing and other medical devices.
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Applications
Silicas exist as white, fluffy powders that are produced through a wet process, yielding silica or silica gel, or a thermal route, yielding pyrogenic (fumed) silica.1
In powdered foods, the silica clings to the particles of the foods and prevents them from clumping. This allows powdery products to remain free-flowing, and other products easy to separate.
Silicon dioxide also functions as a defoaming agent, carrier, conditioning agent, chillproofing agent in malt beverages (like beer) and filter aid.
It’s also used to manufacture materials such as adhesives and paper for food-packaging materials.
As a direct additive, per U.S. FDA regulation, levels of SAS cannot exceed 2% by weight of the food, and as an indirect additive, it can only be used in the amount required to produce the intended functional effect.
Table 1 FDA clearances for silica substances as direct food additives2
21 CFR Reference | Direct Food Additive Clearance |
73.1 | Inks for marking fresh fruits and vegetables |
73.575 | Titanium dioxide mixtures for food |
133.146 | Anti-caking in grated cheese |
160. 105 | Anti-caking in dried eggs |
160.185 | Anti-caking in dried egg yolks |
172.230 | Microencapsulation of flavoring substances |
172.480 | Principal section, free-flowing and anticaking agent in foods |
172.510 | Natural flavoring substances used in conjunction with flavors |
173.340 | Defoaming agent |
182.90 | Substances migrating to food from paper and paperboard products |
EFSA suggests re-evaluation of silicon dioxide
Silicon dioxide has a long history of use as a food additive without any detrimental health effects.3
As a food additive, there is no indication of toxicity of silicon dioxide at its reported uses and use level.
Despite this, the European Food Safety Authority (EFSA) recently urged the European Union (EU) to reevaluate the safety of silicon dioxide (E551) when used as a food additive.3
This is because animal studies have suggested that nano-sized particles can cause inflammatory reactions of the intestinal wall. But it’s unclear if these findings are transferable to humans.3
In their request, EFSA scientists warned that some of the silicon dioxide particles may be smaller than the nano threshold of 100 nm.
Because there have been no long-term studies looking at the safety of nano silicon dioxide, the EFSA could not confirm its safety and, therefore, characterize it as a food additive.
The EFSA urged the EU to change current specifications to include particle size distribution. They suggested that the EU use appropriate statistical descriptors such as range, median, and quartiles, as well as the percentage of particles in nanoscale.
Moreover, while silicon is thought to play a role in bone and collagen formation, a clear function of silicon in humans has not been established and there is no specified acceptable daily intake (ADI) for it.
In their report, however, the EFSA scientists stated that a chronic toxicity study using “an adequately characterized material representative of SAS used as a food additive E 551” would provide appropriate data needed to derive an ADI and the guidelines need for preventing its excess intake over the estimated ADI.
The bottom line
Silicon dioxide has many important applications in the food industry as a food additive. Its functional properties allow for its use as an anticaking agent and carrier.
Silicon dioxide has a safe track record as a food additive and is considered non-toxic, even at high doses.
Concerns, however, have been raised over the SAS materials used in toxicology studies, which may not have covered the full-size range of the nanoparticles that could be present in silicon dioxide as a food additive.
This tasks researchers with evaluating the potential hazards of nano silicon dioxide in human health in order to generate confidence in industry and consumers.
References
- Food and Agriculture Organizations of the United Nations and World Health Organization. Silicon Dioxide, Amorphous [PDF]. 2017.
- U.S Food and Drug Administration. CFR – Code of Federal Regulations Title 21, 2018.
- EFSA ANS Panel. Scientific Opinion on the re-evaluation of silicon dioxide (E551) as a food additive. EFSA Journal 2018; 16(1):5088, 70 pp.
You may also want to read…
- Silicon Dioxide: Applications & Potential Health Benefits
- The Basics of Anti-Caking Agents
- Get Gel-ous with Food Additives
- Maltodextrin: The Multifunctional Ingredient
- Tricalcium Phosphate: A Formulating Superhero [Infographic]
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I want to know more about sio2
Hi Ravinder, thank you for your comment. If there is something specific you would like more information on, feel free to let us know and we may consider expanding on silicon dioxide in future articles.
Thank you, Gavin.
What percentage of sio2 is allowed for human intake as by weight
Thanks
The requirement for silicon remains largely unknown, however, estimates range from 10 to 25 mg/day. And while no tolerable upper intake level has been established for silicon, a safe upper level of 700 mg/day has been suggested (12 mg silicon/kg of bodyweight/day for a 60 kg person).
Thanks!
Gavin
May i know how to produce Silica Gel after pbtained SiO2 from sand .. I nid the preparation of making silica gel for my coursework study . I would really appreciate if you help me to solve my difficulty. Thanks.
Hi Guan, thank you for reading. Here is an article that provides a thorough overview of silica — https://pubchem.ncbi.nlm.nih.gov/compound/Silicon-dioxide#section=DSSTox-Substance-ID
I want manufacturing sinthetic Vanilla Powder
Please suggest me ingredients
Hi Harish,
Thanks for reading. You can use UL’s ingredient search to find ingredients for your product. Here’s the link: https://www.ulprospector.com/
Thank you.