Titanium Dioxide Nanoparticle-Polyphenol Interaction And Their Effect On The Bioavailability And Antioxidant Activity Of Polyphenols

Titanium dioxide(TiO₂)often are used as food additives in the food industry.Studies have found that food additives TiO₂ contains quite a number of nano-sized TiO₂.The surface around titanium atoms has a certain degree of unsaturation due to the lack of adjacent atoms,which is easy for other atoms and molecules to bond.Protein,starch and lipid in food can interact with polyphenols,thereby affecting the bioavailability and bioactivity of polyphenols.Therefore,this paper studies the interaction between TiO₂NPs and polyphenols and its influence on the bioavailability and antioxidant activity of polyphenols,which is of great significance to investigate the functional changes of polyphenols in complex food systems and to guide people to a reasonable diet.The main research results are as follows:1.The chemical structure of polyphenols significantly influenced their binding affinity to TiO₂ NPs surface,with polyphenols possessing vicinal trihydroxy had the higher binding affinity.TiO₂ NPs could reduce the bioavailability of polyphenols in vitro.Additionally,binding to TiO₂NPs surface would reduce the antioxidant activity of polyphenols.2.The primary tea polyphenols,including catechin,epigallocatechin gallate,gallocatechin gallate and epicatechin gallate(C,EGCG,GCG and ECG),decreased significantly after addition of 0.5 wt%TiO₂NPs.The gallocatechin gallate level decreased the most,changing from 101.9±2.7 to 27.2±2.6?g/m L.The TiO₂ NPs also reduced the bioavailability of the tea polyphenols in a dose-dependent manner,which was ascribed to the formation of polyphenol-TiO₂ NP complexes that could not pass through the pores in the dialysis tube used to simulate the gut wall.The presence of the TiO₂ NPs decreased the antioxidant activity of the tea polyphenols within the simulated gastrointestinal tract,which suggests that binding of the polyphenols to the nanoparticle surfaces reduced their ability to inhibit oxidation.3.Adding 0.5 wt%TiO₂ NPs would significantly decrease the total polyphenols content and the main individual polyphenols content of apple juice.Additionally,TiO₂NPs addition reduced the bioavailability and antioxidant activity of apple polyphenols in a dose dependent manner attributing to the formation of polyphenol-TiO₂ NPs charge transfer complexes.The comprehensive results show that TiO₂ NPs can still interact with polyphenols in complex food substrates and affect their biological activity.The food industry should strictly control the amount of TiO₂NPs to avoid possible side effects.