title: Criteria to define a more relevant reference sample of titanium dioxide in the context of food: a multiscale approach.
abstract: Titanium dioxide (TiO2) is a transition metal oxide widely used as a white pigment in various applications, including food. Due to the classification of TiO2nanoparticles by the International Agency for Research on Cancer as potentially harmful for humans by inhalation, the presence of nanoparticles in food products needed to be confirmed by a set of independent studies. Seven samples of food-grade TiO2(E171) were extensively characterised for their size distribution, crystallinity and surface properties by the currently recommended methods. All investigated E171 samples contained a fraction of nanoparticles, however, below the threshold defining the labelling of nanomaterial. On the basis of these results and a statistical analysis, E171 food-grade TiO2totally differs from the reference material P25, confirming the few published data on this kind of particle. Therefore, the reference material P25 does not appear to be the most suitable model to study the fate of food-grade TiO2in the gastrointestinal tract. The criteria currently to obtain a representative food-grade sample of TiO2are the following: (1) crystalline-phase anatase, (2) a powder with an isoelectric point very close to 4.1, (3) a fraction of nanoparticles comprised between 15% and 45%, and (4) a low specific surface area around 10 m2g-1.
authors.affiliation: a UR1268 BIA (Biopolymères Interactions Assemblages) , INRA , Nantes , France.
authors.forename: William
authors.initials: W
authors.lastname: Dudefoi
authors.affiliation: b Institut des Matériaux Jean Rouxel (IMN) , Université de Nantes, CNRS , Nantes , France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Terrisse
authors.affiliation: b Institut des Matériaux Jean Rouxel (IMN) , Université de Nantes, CNRS , Nantes , France.
authors.forename: Mireille
authors.identifier: http://orcid.org/0000-0002-7871-2919
authors.initials: M
authors.lastname: Richard-Plouet
authors.affiliation: b Institut des Matériaux Jean Rouxel (IMN) , Université de Nantes, CNRS , Nantes , France.
authors.forename: Eric
authors.initials: E
authors.lastname: Gautron
authors.affiliation: b Institut des Matériaux Jean Rouxel (IMN) , Université de Nantes, CNRS , Nantes , France.
authors.forename: Florin
authors.initials: F
authors.lastname: Popa
authors.affiliation: b Institut des Matériaux Jean Rouxel (IMN) , Université de Nantes, CNRS , Nantes , France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Humbert
authors.affiliation: a UR1268 BIA (Biopolymères Interactions Assemblages) , INRA , Nantes , France.
authors.forename: Marie-Hélène
authors.identifier: http://orcid.org/0000-0001-7320-3667
authors.initials: MH
authors.lastname: Ropers
mesh_terms: D005502:Food / Q000592:standards*; D005503:Food Additives / Q000737:chemistry* / Q000592:standards; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry* / Q000592:standards; D010316:Particle Size; D013499:Surface Properties; D014025:Titanium / Q000032:analysis* / Q000592:standards
chemical_list: D005503:Food Additives; C009495:titanium dioxide; D014025:Titanium
keywords: E171; TiO2; food; nanoparticle; surface properties