Processing tangerine tomatoes: effects on lycopene-isomer concentrations and profile.

Because lycopene is a powerful biological antioxidant, its delivery to humans is of major concern. cis-Lycopene isomers are more bioavailable than the all-trans isomers and thus more efficiently absorbed. Tangerine tomatoes, whose lycopene isomeric content is almost all tetra-cis, provide a useful food source for comparing cis- and trans-isomer absorption. Tangerine tomatoes were processed into sauce in the Univ. of California, Davis Pilot Plant for subsequent use in a human feeding study described in another publication. Samples were taken at several stages during processing and carotenoids extracted and analyzed for carotenoid-isomer profiles and concentrations. Analyses showed that total lycopene concentration decreased considerably during the 1st step of processing, which included heating and juicing operations. Processing resulted in a large decrease in tetra-cis lycopene concentration accompanied by increases in trans- and other cis-lycopene isomers.