Stability of Lycopene in Oil-in-Water Emulsions

Lycopene can be dissolved within the oil phase of oil-in-water emulsions to increase bioavailability in water-dispersible systems. It is sensitive to oxidative conditions and easily undergoes isomerization at high temperatures. Degradation kinetics and isomerization of lycopene in oil-in-water-emulsions were investigated as a function of thermal treatment and oxygen content. Lycopene degradation was found to follow a first-order kinetics and rate constants were determined. Higher temperatures are directly correlated with increasing lycopene losses. Moreover, thermal treatment leads to a significant decrease of the concentrations of all-trans and 13-cis isomer, while the concentration of the 9-cis isomer increased. Oxygen-free conditions reduce lycopene losses significantly.