Lycopene stability in tomato powders

The chemical stability of lycopene in 2 commercial tomato powders was evaluated during storage. Liquid chromatography and spectral analysis were used to determine lycopene loss and the formation of cis isomers and degradation products. Tomato powder products were stored at 6 and 45 degrees C or under fluorescent light for up to 6 wk. Several lycopene degradation products were tentatively identified in the initial and stored powders. After 6 wk at 45 degrees C, 60% of the lycopene was degraded. At lower storage temperatures the losses were about 30% after 6 wk. Mechanisms of loss appear to be both isomerization and oxidation.