2009_Book_FoodChemistry

236 3 Lipids
name “carotene”, denoting the structure of both
C 9 - end groups (cf. Formulas III, IV, VI or X:
cf. Formulas 3.120, 3.121, 3.122 and 3.128,
respectively). Designations such as α-, β- or
γ-carotene are common names.
Carotenoids are divided into two main classes:
carotenes and xanthophylls. In contrast to
carotenes, which are pure polyene hydrocarbons,
xanthophylls contain oxygen in the form of hydroxy,
epoxy or oxo groups. Some carotenoids of
importance to food are presented in the following
sections.
3.8.4.1.1 Carotenes
Acyclic or aliphatic carotenes
Carotenes I, II and III (cf. Formulas 3.119–
3.122) are intermediary or precursor compounds
which, in biosynthesis after repeated dehydrogenizations,
provide lycopene (IV; see a textbook
of biochemistry). Lycopene is the red color of the
tomato (and also of wild rose hips). In yellow
tomato cultivars, lycopene precursors are present
together with β-carotene (Table 3.56).
Phytoene (I) (3.119)
Phytofluene (II) (3.120)
ξ -Carotene (7,8,7 ′ ,8 ′ -tetrahydro-ψ,ψ-carotene) (III) (3.121)
Lycopene (ψ,ψ-carotene) (IV) (3.122)
Table 3.56. Carotenes (ppm) in some tomato cultivars
Cultivar
Phytoene Phytofluene β-Carotene ξ -Carotene γ-Carotene Lycopene
(I) (II) (VII) (III) (V) (IV)
Campbell 24.4 2.1 1.4 0 1.1 43.8
Ace Yellow 10.0 0.2 trace 0 0 0
High Beta 32.5 1.7 35.6 0 0 0
Jubilee 68.6 9.1 0 12.1 4.3 5.1