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Composition of tomatoes and tomato products in antioxidants (WG1) page 59
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7.1.2.3 IR Spectroscopy
The polyene structure of lycopene gives rise to 2 weak bands at 1629 and 1559 cm -1 ,
(C=C stretching), and a quite strong band at 960 cm -1 (CH out-of-plane deformation).
7.1.2.4 Solubility
Figure 5 : IR spectra of lycopene
Due to its hydrocarbon structure, lycopene is very lipophilic. It is then soluble in
apolar solvents : hexane, light petroleum, benzene, dichloromethane, chloroform and THF. It
is slightly soluble in acetone, ethanol. It is completely insoluble in water.
Its partition coefficient (log P in octanol/water) has been calculated (Cooper et al.
1997): the value is 17.64. Among the carotenoids, it is one of the most apolar compounds, the
xanthophylls have a clalculated log P between 5.82 and 16.
7.1.2.5 Sensitivity
As a highly conjugated polyene, lycopene is particularly susceptible to oxidative
degradation. Physico-chemical factors known to degrade carotenoids in general including
lycopene are : - exposure to oxygen
- elevated temperature
- exposure to light
- extreme pH