Sensory perception of textural properties of cosmetic Pickering emulsions

Objective The increasing interest for the Pickering emulsions is based on the possibility to replace classical emulsifiers by the solid particles. This approach is extremely attractive for the cosmetic field. But, the main difficulty is to obtain stable emulsions with appreciable skin feel. However, there is no information about the texture of such systems. The aim of this study is to formulate and describe the textural properties of cosmetic Pickering emulsions compared with conventional systems. Methods Three metal oxides were selected: titanium dioxide, zinc oxide and silicon dioxide, able to form stable and totally emulsified systems. A conventional emulsifier was used to formulate the emulsion of reference. Finally, the mixture of two emulsifying systems, combining both, surfactant and particles, was also studied. Then, a sensory panel was asked to quantify the intensities of the perception of the seven discriminating attributes. Results Each particle brought its properties to the textural perception of the emulsion. TiO2 particles ensured the whitening effect of the emulsions, SiO2 provided the screech residue, whereas ZnO gave intermediate results. The conventional surfactant was perceived as glossy, greasy and more difficult to spread. The particle/surfactant mixtures gave mostly in‐between results. Conclusions The study shows that the sensory profile of Pickering emulsions is indirectly and directly governed by the particle properties used for the emulsion stabilization: indirectly, through affecting the emulsion orientation (oil in water or water in oil), the droplet organization and viscosity, and directly, through the particle perception on the skin surface. Résumé Objectif L'intérêt croissant pour les émulsions de type Pickering repose sur la possibilité de remplacer les émulsifiants classiques par les particules solides. Cette approche est extrêmement attractive pour le domaine cosmétique. Mais, la principale difficulté est d'obtenir des émulsions stables avec un toucher agréable. Cependant, il n'y a aucune information sur la texture de tels systèmes. Le but de cette étude est de formuler et de décrire les propriétés de texture des émulsions cosmétiques de type Pickering par rapport aux systèmes conventionnels. Méthodes Trois oxydes métalliques ont été sélectionnés: le dioxyde de titane, l'oxyde de zinc et le dioxyde de silicium, capables de former des systèmes stables et totalement émulsifiés. Un émulsifiant conventionnel a été utilisé pour