Finally, radicals can also react wi

Finally, radicals can also react with carotenoids to form radical
adducts. This may occur with alkyl, alkoxyl, and peroxyl
radicals as seen in Eqs. 19–21 (Haila et al., 1997; Mortensen,
2002; Liebler and McClure, 1996). Laser flash and steadystate
photolysis studies of beta-carotene indicate that at least
for this carotenoid, reaction with peroxyl radicals occurs much
more slowly than with alkyl or alkoxyl radicals (Mortensen
and Skibsted, 1988). Iannone et al. showed that beta-carotene
and lutein can quench peroxyl radicals at low oxygen concentrations
using EPR and spin trapping techniques (Iannone et
al., 1998). Laser flash photolysis studies of beta-carotene and
canthaxanthin in aerated solutions of benzene with di-tert-butyl
peroxide and toluene have provided evidence that the benzylperoxyl
radical produced under these conditions reacts with the
carotenoids to produce adducts that decay in a first-order reaction
(