Overall, the Food Directorate's comprehensive review of the available science of TiO₂ as a food additive showed:

Titanium Dioxide is largely produced by the reduction of titanium tetrachloride, obtained in turn from chlorination of natural rutile, synthetic rutile derived from ilmenite or even slags rich in TiO2 produced by metallurgical treatment of ilmenite. TiO2 is also manufactured by treatment of ilmenite with sulfuric acid. Raw materials and the respective production processes employed in the manufacturing of Titanium Dioxide are listed below.

Titanium dioxide is an inert earth mineral used as a thickening, opacifying, and sunscreen ingredient in cosmetics. It protects skin from UVA and UVB radiation and is considered non-risky in terms of of skin sensitivity. Because it is gentle, titanium dioxide is a great sunscreen active for sensitive, redness-prone skin. It’s great for use around the eyes, as it is highly unlikely to cause stinging.

TiO₂ is also used in oral pharmaceutical formulations, and the Pharmaceutical Excipients handbook considers nano-sized TiO₂ a non-irritant and non-toxic excipient. Despite the fact that TiO₂ submicron- and nano-sized particles are widely used as food and pharmaceutical additives, information on their toxicity and distribution upon oral exposure is very limited.

Production

Le produit obtenu par cette méthode est constitué de 29,4 % en masse de ZnS et 70,6 % en masse de BaSO₄. Il existe des variations, par exemple l'adjonction de chlorure de zinc à la pâte avant chauffage produit un pigment plus riche en ZnS³.

1. Properties: white powder, a mixture of zinc sulfide and barium sulfate.

1. Using roasting and leaching method. The reaction equation is as follows:

Our scientific experts applied for the first time the 2018 EFSA Scientific Committee Guidance on Nanotechnology to the safety assessment of food additives. Titanium dioxide E 171 contains at most 50% of particles in the nano range (i.e. less than 100 nanometres) to which consumers may be exposed.  

Infrared analysis showed that the characteristics bands for the bare nanoparticles are still exhibited in the vitamins@P25TiO₂NPs spectra, such as a wide peak in 450–1028 cm⁻¹ related to the stretching vibration of Ti-O-Ti and other peaks in 1630 cm⁻¹ and 3400 cm⁻¹, which represent the surface OH groups stretching. The IR spectrum of vitaminB2@P25TiO₂NPs showed signs of binding between compounds. The OH bending peak (1634 cm⁻¹) corresponding to bare nanoparticles disappeared, and the NH₂ bending band characteristic of vitamin B2 appeared (1650 cm⁻¹). The IR spectrum of vitaminC@P25TiO₂NPs also showed signs of successful functionalization. Bands at 1075 cm⁻¹; 1120 cm⁻¹; 1141 cm⁻¹ were observed, which are originated by CO-C vibrations present in the vitamin C. The intense band at 1672 cm⁻¹ is attributed to the C = O stretching in the lactone ring while the peak at 1026 cm⁻¹ is ascribed to the stretching vibration Ti-O-C. Wide bands at 3880–3600 cm⁻¹ are related to stretching vibration OH groups, but those disappear in the modified nanoparticles spectrum. These observations confirm the interactions between the P25TiO₂NPs and the vitamins [35].