Characterization of silicium dioxide (SiO2) nanoparticles in the food additive E 551 by Scanning Electron Microscopy (SEM) combined with energy-dispersive x-ray spectroscopy (EDX)

Silicon dioxide (SiO2, amorphous silica) is a food additive approved in the EU with the designation number E 551. It is mainly used in powdered foods as a separating agent or anti-caking agent. Furthermore, it can be used as filler and as carrier for emulsifiers, colourings and flavourings.

Silicon dioxide as a food additive is under public discussion due to controversial views on the declaration obligation of the substance as an engineered nanomaterial. According to the Food Information Regulation (EU) No. 1169/2011, all food ingredients that are present in a food in the form of engineered nanomaterials must be clearly listed in the list of ingredients. The name of such ingredients must be followed by the word "nano" in brackets. So far, there are only very few E 551-containing foods on the market with nano-labelling of E 551.

The SiO2 used for this purpose is an industrially manufactured product in powdered form. It consists of amorphous agglomerated and aggregated granules whose particle sizes are mainly in the microscale size range. However, these aggregates consist of nanoscaled constituent particles (also called “primary particles”).

This dataset contains SEM images showing the morphology of SiO2 aggregates in the pristine food additive called “Sipernat®22S”. In the high magnification images (50.000x - 300.000x) the constituent nanoparticles can be visualised. Basic information about the SEM setup and the sample preparation can be found in the attached txt-file. All in all, the obtained SEM results show, that the primary particles size of SiO2 particles within the aggregates are in the size range of ca. 15 – 30 nm.


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