NO - Besoin d'assistance

Composition of tomatoes and tomato products in antioxidants (WG1) page 35
__________________________________________________________________________________________
Giovanelli et al.(1999) evaluated the variation in the antioxidant content at seven
stages during vine and post-harvest ripening on two genotypes (Normal Red and Crimson) of
the tomato cv. Moneymaker grown in a greenhouse. In vine-ripened tomatoes lycopene and β-
carotene concentrations progressively increased linearly during the ripening process.
Conversely, in post-harvest-ripened fruit lycopene and β-carotene accumulation followed an
exponential trend. At the end of the experiments, the lycopene and β-carotene concentration
(roughly 125-130 and 12 mg/kg fresh matter respectively) in post-harvest-ripened tomatoes
was almost twice the value reached in vine-ripened tomatoes (roughly 75-80 and 5-7 mg/kg
fresh matter respectively) having the same colour (a*/b*) index. As a consequence, adequate
post-harvest storage can result in increased fruit lycopene content. β-carotene synthesis was
observed on both genotypes under both ripening conditions for a longer time than that usually
considered in tomato ripening studies, particularly from Koskitalo and Ormrod (1972) who
observed that β-carotene synthesis stopped after tomato colour had changed from orange into
red.
All the studies indicate the same trend of lycopene content to sharply increase during
the last period of ripening (from pink stage). However it remains difficult to compare the
results of the previous studies because the cultivars used were different and the stages
considered were not the same and described with subjectivity. The data available in the papers
do not generally allow to calculate temperature sums which could allow comparisons or
modeling.
6.1.6. Growth and development regulators
The following growth and development regulators have been experimented on tomato
plants in various conditions :
DCPTA (2-(3,4-dichlorophenoxy)triethylamine) is a bioregulator of lipid and protein
synthesis which has been shown to increase the harvestable yield of numerous crop plants by
maintaining a balanced partitioning of photosynthetate between plant growth and crop yield.
CPTA (2-(4-Chlorophenylthio)triethylamine hydrochlorid) is a bioregulator
considered as an enhancer of protein synthesis and a carotenoid inducer, stimulator of the
disappearance of chloroplasts and the accumulation of chromoplasts (Robertson et al, 1995).