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Composition of tomatoes and tomato products in antioxidants (WG1) page 23
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In fruit pericarp sections stored at various temperatures, Hamauzu et al.(1998) have
observed that, at 20°C, the biosynthesis and accumulation of phytoene and lycopene were
fast, and those of β-carotene was slow; by contrast, at 30°C, the biosynthesis and
accumulation of lycopene and β-carotene were fast and phytoene accumulation was slow; at
35°C the biosynthesis and accumulation of β-carotene was fast but slower that at 30°C and
accumulation levels of phytoene and lycopene were very slow. Hamauzu et al.(1998) have
postulated that high temperature (35°C) inhibits the accumulation of lycopene in tomato fruit
because of the stimulation of the conversion of lycopene to β-carotene.
In conclusion, the formation of lycopene depends on temperature range and seems to
occur between 12°C and 32°C (Leoni, 1992). It is optimum in cell suspension culture of
VFNT tomato for temperature between 18 and 26°C (Robertson et al, 1995). It is also
optimum in the temperature range 16-26°C for tomato fruits (cv. Sunny) harvested at the
pink-ripe stage and stored for ripening (Türk et al.1994) as presented in Table 8. The
production of lycopene is hindered by excessive sunlight and the best conditions are
temperature high enough together with dense foliage to protect fruit from direct exposure to
the sun (Leoni, 1992). However in processing tomatoes, lycopene accumulation was enhanced
by 5% at incubation temperatures of 30 and 34°C and by 33% at 37°C while lycopene
accumulation declined in salad tomatoes above 30°C (Boothman et al, 1996). Indeed,
processing tomatoes may often be exposed to temperatures of 35-40°C during the storage
period prior to processing and over-ripening may occur accompanied with high lycopene
content.
Table 8. Total lycopene formation (mg/kg fresh matter) in tomato fruits (cv. Sunny)
harvested at the pink-ripe stage and stored under the conditions of 0 and 18°C and 90%
Relative Humidity (after Türk et al, 1994)
Storage temperature Storage duration (weeks)
(°C) 1 2 3 4 5 6
Total lycopene 0 3.58 3.50 4.87 5.63 15.37 15.66
18 3.58 4.79 7.75 37.83 - -