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

Abstract

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.