Impact of food additive titanium dioxide on the polyphenol content and antioxidant activity of the apple juice

Food grade titanium dioxide (TiO 2 ) usually contains a nanosized fraction, while only a few studies had investigated the effects of TiO 2 nanoparticles (NPs) on the other food components via oral exposure. This work investigated the impact of TiO 2 NPs on the content, bioaccessibility and antioxidant activity of polyphenols in the apple juice. Results indicated that adding 500 mg/100 g TiO 2 NPs significantly decreased the contents of total polyphenol and the main individual polyphenols in the apple juice, which was attributed to the formation of polyphenol-TiO 2 NPs charge transfer complexes aggregation. Additionally, the addition of TiO 2 NPs reduced the bioaccessibility and antioxidant activity of apple polyphenols in a dose dependent manner. This study indicated that TiO 2 NPs can bind polyphenols in the complex food matrix, and provided valuable insights into the influence of food grade TiO 2 NPs on the other food components after oral consumption.