Food Additive Titanium Dioxide and Its Fate in Commercial Foods

Titanium dioxide (TiO₂) is one of the most extensively utilized food additives (E171) in the food industry. Along with nanotechnology development, the concern about the presence of nanostructured particles in E171 TiO₂ and commercial food products is growing. In the present study, the physicochemical properties of commercially available E171 TiO₂ particles, including particle size distribution, were investigated, followed by their cytotoxicity and intestinal transport evaluation. The fate determination and quantification of E171 TiO₂ in commercial foods were carried out based on the analytical procedure developed using simulated foods. The results demonstrated that TiO₂ is a material mainly composed of particles larger than 100 nm, but present as an agglomerated or aggregated particle in commercial foods with amounts of less than 1% (wt/wt). Titanium dioxide particles generated reactive oxygen species and inhibited long-term colony formation, but the cytotoxicity was not related to particle size distribution or particle type (food- or general-grade). All TiO₂ particles were mainly transported by microfold (M) cells, but also by intestinal tight junction. These findings will be useful for TiO₂ application in the food industry and predicting its potential toxicity.