Although barium sulfate is almost completely inert, zinc sulfide degrades upon exposure to UV light, leading to darkening of the pigment. The severity of this UV reaction is dependent on a combination of two factors; how much zinc sulfide makes up the pigments formulation, and its total accumulated UV exposure. Depending on these factors the pigment itself can vary in shade over time, ranging from pure white all the way to grey or even black. To suppress this effect, a dopant may be used, such as a small amount of cobalt salts, which would be added to the formulation. This process creates cobalt-doped zinc sulfide. The cobalt salts help to stabilize zinc sulfide so it will not have as severe a reaction to UV exposure.

Titanium dioxide can amplify and brighten white opacity because of its exceptional light-scattering properties. In food and drugs, these properties help to define colors clearly and can prevent products from UV degradation. 

Is titanium dioxide safe?

The paints and coatings industry reduced their offtakes which coupled with the drop in the crude oil prices and availability of cheaper imports from the Asian market led to the fall in titanium dioxide prices. The demand decreased significantly in the fourth quarter along with the slow manufacturing due to high inflation rates keeping the price trends of the commodity in the negative zone.

Worldwide Lithopone Industry to 2027 - Use of Lithopone in the Paints & Coatings Industry is Driving Growth - ResearchAndMarkets.com

Though the regulated use of titanium dioxide in food products is legal in the U.S. and Canada, it's banned in some other countries, notably throughout Europe. In May 2021, the European Food Safety Authority announced that titanium dioxide can no longer be considered safe as a food additive.

What is titanium dioxide? Why is it used in food products?

Algaecidal effect of Lithopon: After 5 years of exposure to weathering in Alpen (Lower Rhine)  

Titanium dioxide is used in a wide range of food products and consumer goods – from candy to sunscreen and house paint. The U.S. Food and Drug Administration maintains that the regulated use of titanium dioxide, specifically as a color additive in food, is safe under some restrictions.

Alterations in gut microbiota

Abstract

Report Overview:

A study published in the Journal of Agricultural and Food Chemistry in 2019 sought to examine the effects of titanium dioxide on intestinal inflammation. Researchers did this by feeding rats titanium dioxide nanoparticles and found that, after the course of two to three months, the animals had lower body weights and induced intestinal inflammation. The researchers also found the nanoparticles altered gut microbiota composition and aggravated chronic colitis. The rats also experienced reduced populations of CD4+T cells (which are cells that help organize immune responses by prompting other immune cells to fight infection), regulatory T cells, and white blood cells in mesenteric lymph nodes. The researchers wrote: “Dietary TiO2 nanoparticles could interfere with the balance of the immune system and dynamic of gut microbiome, which may result in low-grade intestinal inflammation and aggravated immunological response to external stimulus, thus introducing potential health risk.”