Lycopene: Heterogeneous Catalytic E / Z Isomerization and In Vitro Bioaccessibility Assessment Using a Diffusion Model

Highly efficient heterogeneous catalytic E / Z isomerization of lycopene was achieved using an iodine‐doped titanium dioxide (I‐TiO 2 ) catalyst prepared by sol‐gel method. The effects of reaction temperature and reaction time were investigated in detail. The maximum total Z ‐ratio of lycopene exceeded 78% after 2 h of refluxing at 75 °C in ethyl acetate. Moreover, lycopene samples with a series of total Z ‐ratios were prepared and the bioaccessibility of these samples was estimated using a diffusion model, the results showed that the bioaccessibility of lycopene markedly increased conforming to a linear regression model with increasing of the total Z ‐ratio of lycopene from 3.6% to 78.5%. Furthermore, the specific role of the microstructure and melting point of 3.6% and 78.5% total Z ‐ratio of lycopene was also investigated to understand the probable mechanism for the enhanced bioaccessbility of ( Z )‐lycopenes.