Modeling Lycopene Degradation and Isomerization in the Presence of Lipids

The kinetics of thermally induced degradation and isomerization of lycopene in olive oil, fish oil, and an olive oil/tomato emulsion were studied in detail. Special attention was paid to the isomerization reactions using a multi-response modeling approach. The type of oil had a significant impact on lycopene degradation kinetics, being faster in fish oil compared with olive oil. The estimated kinetic parameters to describe lycopene degradation in olive oil were not significantly different from those in an olive oil/tomato emulsion. The overall Z-isomer formation and elimination in olive oil, fish oil, and olive oil/tomato emulsion was similar. Only the kinetic parameters for 13-Z-lycopene formation differed significantly in the two oils. Although the isomerization rate constants for the emulsion were lower than for olive oil, the isomerization reactions showed similar temperature dependency. This study shows that the kinetics of thermally induced degradation and isomerization of lycopene in oil and in an olive oil/tomato emulsion can be described using the same model. The food system, however, has an influence on the model parameters, especially on the rate constants.