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Composition of tomatoes and tomato products in antioxidants (WG1) page 21
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Crimson) of the tomato cv. Moneymaker grown in a greenhouse. Instrumental determination
of red colour and evaluation of a*/b* index (Hunter’s ratio of red-to-green component of
colour measured with a tristimulus Minolta Chromameter mod CR-210) made on the whole
fruit skin were the most sensitive and significant indicators for fruit maturity, but they did not
show a direct, unequivocal correlation with the lycopene content, since the same a*/b* value
could correspond to lycopene contents differing by 100%.
From various sources of data in the 70’s, tomato lycopene content may range from 43
to 181 mg/kg fresh matter, with most frequent values between 55 and 80 (Davies and Hobson,
1981). Sharma and Le Maguer (1996b) established that skins contained about five times more
lycopene (540 mg/kg fresh matter; wet basis) than the whole tomato pulp (110 mg/kg). Most
of the lycopene is probably attached to the insoluble and fibre portion of the tomatoes. The
lycopene content in tomato pulp ranged from 64.6 to 107 mg/kg fresh matter (according to
cultivars) whereas it ranged from 354 to 536 mg/kg in the wet insoluble fraction and from
0.074 to 0.34 mg/kg in the soluble fraction. It would be expected that tomatoes with high
insoluble solids would contain more lycopene. In addition, Moretti et al.(1998) have shown
that fruit bruising at the breaker stage could significantly decrease (-37%) the total
carotenoids content in the locular tissue of tomato fruit at the ripe stage.
Many factors may influence the concentration of lycopene in tomato fruit:
environmental factors (light, temperature) and cultural practices (variety, mineral nutrition,
water alimentation, harvest date through ripening stage...).
6.1.2. Influence of temperature
McCollum (1954) had observed that tomato fruits exposed to direct sunlight in the
field often developed poor colour due primarily to a low content of lycopene, because of the
high temperatures of the exposed fruits. Lycopene synthesis in excised fruits from cultivars
with various strains of pigments was drastically inhibited at 32°C in every strain which
produced this pigment (Tomes, 1963).
From the breaker point, Koskitalo and Ormrod (1972) distributed greenhouse-grown
tomato plants (c.v. Early Red Chief) in controlled environment chambers at 4 night/day