Lycopene is an antioxidant that is present in red- and pink-colored fruits and vegetables. As well as being used as a food coloring, it is also used in supplements and functional foods and beverages.
Red tomatoes typically contain 90-95% of their lycopene as the all-trans-isomer, reported to be the most stable form. In tangerine tomatoes, on the other hand, the lycopene is also present as tetra-cis-lycopene, a geometric isomer of all-trans-lycopene. Geometric isomers refer to two or more substances that have the same chemical make-up but the arrangement of the constituent elements is different, giving the substances different properties.
The new study, published in Molecular Nutrition & Food Research, follows earlier studies by the Ohio State University and published in the International Journal of Food Sciences and Nutrition and the Journal of Agricultural and Food Chemistry that also found greater bioavailability of lycopene from tangerine tomatoes.
“We attribute this increase in bioavailability to tangerine tomatoes being rich in cis-lycopene and this lycopene present in lipid-dissolved globular structures in chromoplasts,” wrote the researchers. “In contrast, lycopene in red tomatoes, present as all-trans-lycopene, exists in large crystalline aggregates contributing to poor solubilization and comparatively lower bioavailability.
“Tangerine tomatoes are a unique hybrid with the ability to greatly increase plasma lycopene and could represent a unique source of lycopene for studies of chronic disease prevention.
“If increased plasma lycopene is responsible for a decreased risk for certain chronic diseases, the tangerine tomato is a novel, highly bioavailable source of lycopene allowing individuals to consume reasonable amounts of tomatoes while still conferring health benefits.”
Working with scientists from Virginia Polytechnic Institute and State University and Hohenheim University (Germany) the Ohio State scientists recruited 11 people to participate in their randomized cross-over trial. Participants were randomly assigned to eat two meals with one supplemented with 10 mg lycopene from tangerine tomato (Solanum lycopersicum L., hybrid FG10-314) juice (94% cis) or 10 mg of lycopene from red tomato (Solanum lycopersicum L., hybrid derived from OH8245 × OH8243) juice (10% cis).
Blood samples showed that lycopene bioavailability was increased 8.5-fold in the tangerine tomato group, compared to red tomato juice. The fractional absorption was 47.7% and 4.98% from tangerine tomato and red tomato juices, respectively.
The researchers did note, however, that there was a lot of variability among the study participants.
“These results justify using tangerine tomatoes as a lycopene source in studies examining the potential health benefits of lycopene-rich foods,” they concluded.
Source: Molecular Nutrition & Food Research
Volume 59, Number 4, Pages 658-669, doi: 10.1002/mnfr.201400658
“Enhanced bioavailability of lycopene when consumed as cis-isomers from tangerine compared to red tomato juice, a randomized, cross-over clinical trial”
Authors: J.L. Cooperstone, R.A. Ralston, K.M. Riedl, et al.