Food Chemistry

3.8 Unsaponifiable Constituents 235

Fig. 3.46.Tocopherol and tocotrienol analysis by HPLC (according toCavinsandInglett, 1974). 1α-Tocopherol,
2 α-tocotrienol, 3β-tocopherol, 4γ-tocopherol, 5β-tocotrienol, 6γ-tocotrienol, 7δ-tocopherol, and 8δ-tocotrienol

They provide the intensive yellow, orange or red
color of a great number of foods of plant ori-
gin (Table 3.55; cf. also 17.1.2.3 and 18.1.2.3.2).
They are synthesized only by plants (see a text-
book of biochemistry). However, they reach ani-
mal tissues via the feed (pasture, fodder) and can
be modified and deposited there.
A well known example is the chicken egg yolk,
which is colored by carotenoids. The carotenoids

in green plants are masked by chlorophyll. When
the latter is degraded, the presence of carotenoids
is readily revealed (e. g. the green pepper be-
comes red after ripening).

Table 3.55.Carotenoids in various food

Food Concen- Food Concen-
tration tration
(ppm)a (ppm)a

Carrots 54 Peaches 27
Spinach 26–76 Apples 0.9–5. 4
Tomatoes 51 Peas 3–7
Apricots 35 Lemons 2–3

aOn dry weight basis.

3.8.4.1 ChemicalStructure,Occurrence

Other carotenoids are derived by hydrogena-

tion, dehydrogenation and/or cyclization of

the basic structure of the C 40 -carotenoids

(cf. Formula 3.117). The cyclization reaction can

occur at one or both end groups. The differences

in C 9 -end groups are denoted by Greek letters

(cf. Formula 3.118).

(3.117)

A semisystematic nomenclature used at times

has two Greek letters as a prefix for the

generic

(3.118)