e171 in food

Titanium dioxide, often referred to as TiO2, exists in two primary forms rutile and anatase. Rutile TiO2 is renowned for its exceptional optical properties and higher refractive index, making it the preferred choice for applications requiring maximum brightness and durability. This form of titanium dioxide is characterized by its dense particle structure, providing superior weatherability and resistance to discoloration, essential traits for products exposed to the elements.

...

At the present JECFA meeting, the committee considered additional toxicological studies relevant to the safety assessment of the chemical that investigated its toxicokinetics, acute toxicity, short-term toxicity, long-term toxicity and carcinogenicity, genotoxicity, and reproductive and developmental toxicity, as well as special studies addressing its short-term initiation/promotion potential for colon cancer. The experts acknowledged that a large number of toxicological studies have been conducted using test materials, including nanoparticles, having size distributions and physico-chemical properties not comparable to real-world uses of titanium dioxide as a food additive. The studies on non-representative materials were evaluated by JECFA, but the committee concluded that such studies are not relevant to the safety assessment of the additive.

...

 With the development of science and technology, various pigments have emerged. Inorganic pigments are facing serious challenges. Nanomaterials are a new class of materials with mesoscopic dimension developed at the end of the 20th century. They are now developing in a low-dimensional and complex direction. . In recent years, nano-Lide powder has been put into industrial production. The zinc sulphate solution is prepared in the same way as the traditional method. In the organic phase (such as benzene), the production cost is high, the wastewater is difficult to recycle, the organic solvent in the production process and the final immersion. Slag is likely to cause environmental pollution, and its development is severely limited.

...

Lithopone was developed in the 1870s as a substitute for lead carbonate (lead white), to overcome its drawbacks of toxicity and poor weathering resistance. Within a few years, titanium dioxide displaced lithopone to become the white pigment (PW6) par excellence in the industry and the world’s best-selling inorganic pigment. However, titanium is a product whose price is subject to large price variations due to product availability. These price increases affect the competitiveness of finished products, and so the search for an alternative to titanium dioxide has generated a variety of possibilities to optimise its use. 

...