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Composition of tomatoes and tomato products in antioxidants (WG1) page 66
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In an in vitro experiment the relative antioxidant activities of a range of carotenoids
were assessed by the extent of their ability to scavenge the ABTS radical cation (Miller et al.
1996). The results were expressed as Trolox Equivalent Antioxidant Capacity (TEAC) values.
In the ability to scavenge the radical cation under the conditions of this experiment, lycopene
was the most effective (Table 25).
Carotenoid TEAC (mM)
lycopene 2.9
β-carotene 1.9
Lutein 1.5
Canthaxanthin 0.02
Table 25 : TEAC values of some carotenoids (from Miller et al. 1995)
Mortensen and Skibsted (1997) have shown that lycopene is among the most efficient
carotenoid free radical scavengers, because the lycopene radical cation is more stable than
many other carotenoid radical cations.
Conclusion for lycopene.
In summary, lycopene is the main carotenoid in tomato, it is the characteristic pigment
of this fruit confering its red colour. It is a hydrocarbon molecule containing 11 conjugated
double bonds, this particular chemical structure is responsible for the physico-chemical
properties of the molecule. It is a lipophilic molecule, completely insoluble in water. When
isolated, lycopene is sensitive to oxygen and light and can isomerize easily. Like other
carotenoids, it presents antioxidant properties demonstrated in vitro: inhibition of singlet
oxygen, quenching of free radicals.