Titanium dioxide (TiO₂) is a naturally occurring mineral that is mined from the earth, processed and refined, and added to a variety of foods, as well as other consumer products. White in color, it is used to enhance the color and sheen of certain foods and is also key for food safety applications. In its natural state it exists in different bulk crystalline forms, such as anatase and rutile, but during processing it is ground into a very fine powder.

As mentioned above, these oxide NPs are harmful in part because both anatase and rutile forms are semiconductors and produce ROS. Particularly, P25 kind has band-gap energies estimated of 3.2 and 3.0 eV, equivalent to radiation wavelengths of approximately 388 and 414 nm, respectively. Irradiation at these wavelengths or below produces a separation of charge, resulting in a hole in the valence band and a free electron in the conduction band, due to the electron movement from the valence to conduction bands. These hole–electron pairs generate ROS when they interact with H₂O or O₂ [43,44]. It was described that they can cause an increase in ROS levels after exposure to UV-visible light [45]. The NBT assay in the studied samples showed that bare P25TiO₂NPs produce a large amount of ROS, which is drastically reduced by functionalization with vitamin B2 (Fig. 5). This vitamin, also known as riboflavin, was discovered in 1872 as a yellow fluorescent pigment, [46] but its function as an essential vitamin for humans was established more than sixty years later, and its antioxidant capacity was not studied until the end of the XX century [47,48]. This antioxidant role in cells is partially explained because the glutathione reductase enzyme (GR) requires it for good functionality. This enzyme is the one in charge of the conversion of oxidized glutathione to its reduced form which acts as a powerful inner antioxidant and can quench the ROS [49,50]. The cost of this action is that the glutathione is converted to the oxidized form and needs to be recovered by the GR. Consequently, the cells need more vitamin B2. Another glutathione action is the protection against hydroperoxide. This activity is also mediated by riboflavin. Therefore, local delivery of this vitamin seems to significantly help the cells in their fight to keep the oxidative balance, once they are exposed to high levels of ROS.

Tinting(contrast to the sample)

Developing new Lithopone formulations, one that enhances the properties of the existing Lithopone is anticipated to boost the demand for Lithopone white pigment during the forecast period. Reinforced Lithopone is one such development, wherein a copolymer is added to the polymerization reaction to yield Lithopone with an increased weather resistance and an anti-ultraviolet property. Moreover, development of nano-scale Lithopone is also anticipated to attract market interest during the forecast period.

The FDA's Code of Federal Regulations allows for the legal, regulated use of titanium dioxide in food products, under some restrictions.

Titanium dioxide has similar uses in non-food products. It is used in sunscreen as effective protection against UVA/UVB rays from the sun, which creates a physical barrier between the sun’s rays and the skin. It’s also used to whiten paint, paper, plastic, ink, rubber, and cosmetics.