In vitro gastrointestinal stability and Caco-2 cell cytotoxicity of TiO2 and SiO2 (nano)particles from confectionary products.

The effect of an in vitro gastrointestinal assay on the characteristics of nanoparticles from food additives TiO₂ (E171) and SiO₂ (E551) present in confectionaries was determined by spICP-MS. No significant differences were detected in particle size distribution regardless of the phase of the in vitro stage and the confectionary products, with particles present as aggregates/ agglomerates. The percentage of TiO₂ as nanoparticle form was found to be less than 50 % during the in vitro gastrointestinal digestion process, whereas SiO₂ nanoparticles could not be detected due to the high LOD in size obtained (142 nm). The bioaccessible fractions of intestinal extracts showed a 5 % content for both particle types, suggesting their limited absorption in the body. MTT cytotoxicity assay with Caco-2 cells exposed to gastrointestinal extracts from confectionery products revealed an average cytotoxic effect of 40 % for all products tested which was attributed to the food matrix components rather than (nano)particles.