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

Area of Science:

• Catalysis
• Materials Science
• Nutritional Science

Background:

• Lycopene, a potent antioxidant, exists in various isomeric forms, with Z-isomers potentially offering enhanced bioavailability.
• Efficiently converting all-trans lycopene to Z-isomers is crucial for maximizing its health benefits.
• Developing effective catalysts for lycopene isomerization is an active area of research.

Purpose of the Study:

• To develop a highly efficient heterogeneous catalyst for the E/Z isomerization of lycopene.
• To investigate the impact of reaction conditions on the isomerization process.
• To evaluate the effect of lycopene isomerization on its bioaccessibility.

Main Methods:

• Preparation of an iodine-doped titanium dioxide (I-TiO2) catalyst using the sol-gel method.
• Heterogeneous catalytic isomerization of lycopene under varying temperatures and reaction times.
• Analysis of lycopene E/Z ratios using spectroscopic techniques.
• Estimation of lycopene bioaccessibility using a diffusion model.

Main Results:

• The I-TiO2 catalyst achieved a maximum total Z-ratio of lycopene exceeding 78% after 2 hours of refluxing at 75 °C.
• Lycopene bioaccessibility showed a marked, linear increase with the total Z-ratio, from 3.6% to 78.5%.
• Microstructure and melting point analysis provided insights into the enhanced bioaccessibility of (Z)-lycopenes.

Conclusions:

• Iodine-doped titanium dioxide is a highly effective catalyst for lycopene E/Z isomerization.
• Increased Z-isomer content significantly enhances lycopene's bioaccessibility.
• This catalytic approach offers a promising strategy for improving lycopene's nutritional value.