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Composition of tomatoes and tomato products in antioxidants (WG1) page 58
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The fine structure is characterized by a comparison between the size of the 2 bigger
peaks of the absorption spectra (figure 4). The numerical notation is %III/II. In this notation,
the baseline or zero value is taken as the minimum between the 2 peaks. The peak height of
the longest-wavelength absorption band is designated as III, that of the middle absorption
band as II. Spectra fine structure is then expressed as the ratio of the peak heights III/II as a
percentage. The table 22 gives the value of % III/II for lycopene in ethanol and light
petroleum.
Figure 3: UV-visible absorption spectra of lycopene
λ max (nm) % III/II εmol
solvent
448 474 505 acetone
455 487 522 180600 (at 487 nm) benzene
458 484 518 chloroform
446 472 503 65 ethanol
444 470 502 65 184900 (at 470 nm) light petroleum
absorbance
Table 22 : UV/vis spectroscopic data of lycopene.
O
II
II
wavelength
Figure 4 : spectral fine structure. Calculation of %III/II for a carotenoid
III II
O