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.

二氧化硅（Silicon dioxide，SiO₂，无定形二氧化硅）是欧盟获批的食品添加剂，编号为E 551。其主要用于粉状食品中，作为分离剂或抗结剂；此外还可作为乳化剂、着色剂与调味剂的填充剂及载体。作为食品添加剂的二氧化硅目前正处于公众讨论之中，缘由是其作为工程纳米材料的标识义务存在争议。根据《食品信息条例（EU）No. 1169/2011》，所有以工程纳米材料形式存在于食品中的配料，必须在配料表中明确标注，且该配料名称后需紧跟括号内的"nano"字样。截至目前，市场上带有E 551纳米标识的含E 551食品极少。本数据集所用的二氧化硅为工业生产的粉状产品，由无定形的团聚与聚集颗粒组成，其整体粒径主要处于微米级范围，但这些聚集体由纳米级的初级颗粒（亦称"一次颗粒"）构成。本数据集包含扫描电子显微镜（Scanning Electron Microscope，SEM）图像，展示了名为"Sipernat®22S"的原始态食品添加剂中二氧化硅聚集体的形貌。在高倍率图像（50,000倍至300,000倍）中，可观测到构成该聚集体的纳米颗粒。关于SEM实验设置与样品制备的详细信息，可参见附带的txt文件。总体而言，所得SEM结果表明，聚集体内二氧化硅初级颗粒的粒径约为15–30 nm。