Size characterisation of TiO2 nanoparticles present in the sugar coating of chewing gum (and similar confectionery products) by centrifugal liquid sedimentation

Titanium dioxide (TiO ₂ , INS No 171) is a still widely applied food colorant outside the European Union. The possible health risk related to the consumption of TiO ₂ is most probably also related to its particle size distribution. Centrifugal liquid sedimentation (CLS) is a fast and robust method that can be applied for high-resolution particle size distribution measurement of various nanomaterials. It was successfully applied in the characterisation of food-grade titanium dioxide extracted from sugar-coated confectionery products, such as chewing gum. This protocol summarises the details of such a disk centrifuge based analysis procedure and discusses also the limitations of the method.