What is Titanium dioxide?

Titanium dioxide (TiO2) is a stable, non-toxic inorganic material. It exists as a white powdery solid with a very high refractive index and is widely used as a white pigment. TiO2 is also a semiconductor material that produces electron/hole pairs when excited by photons with energies equal to or above the band gap of titanium dioxide. This is essential for its photocatalytic properties. It also scatters and absorbs ultraviolet light.

Applications

TiO2 for the food industry

In the United States, Titanium dioxide is approved by the FDA for use as a colouring agent in food, drugs and cosmetics, including sunscreens. It can be used to enhance the colour and shine of baked goods, carbonated beverages, coated confections, dairy products, cheese, ice cream, frozen desserts, chewing gum, non-dairy creamers, dried soups, pet food and tattoo ink.

However, Titanium dioxide is a potentially harmful food colouring additive. It has no nutritional or preservative properties and is only used to add whiteness and brightness to food surfaces. A safety assessment by the European Food Safety Authority (EFSA) has shown that when humans ingest food-grade titanium dioxide, small particles (or "nanoparticles") of titanium dioxide may accumulate in the body over time and cause genetic damage. The accumulation of titanium dioxide nanoparticles in the body may also damage the immune and nervous systems. However, titanium dioxide is still used in food in the United States, the United Kingdom, Canada, Japan, Australia and New Zealand.

TiO2 for Pharmaceuticals

Titanium dioxide is commonly used in the pharmaceutical industry as a pigment in pharmaceutical products such as gelatin capsules, tablet coatings and syrups. It has been used in sunscreens to block UVA and UVB rays due to its excellent UV resistance, similar to zinc oxide. It also has been used as a biomaterial in orthopaedic implants for hip and knee replacements and as a component in dental products such as implants.