Selection of the genotype with the highest vita-min C content for a given commodity is a much
more important factor than climatic conditions
and cultural practices in producing high amounts
of vitamin C at harvest. Among preharvest factors
light intensity and temperature are the most impor-tant in determining the final vitamin C content of
the commodity. Pruning and thinning of fruit trees
determine their crop load, which affects fruit size
and composition, including vitamins. Other pre-harvest factors have a relatively minor direct effect
on the vitamin C content of fruits and vegetables.
Many harvesting and postharvest handling pro-cedures influence the nutritional quality of fruits
and vegetables. Much of the available information
is about AA, which appears to be the most sensi-tive to postharvest losses. Oxidation can occur in
the presence of catalysts, oxidase enzymes, or as a
result of heat during processing. Therefore, vita-min C losses continue through postharvest han-dling, processing, cooking, and storage of fruits
and vegetables. Additional research is needed to
investigate the effects of postharvest handling pro-cedures on nutrients in fresh fruits and vegetables.
Also, the possible effects on nutritional quality of
those procedures that have not been evaluated
need to be elucidated. Any new harvesting or
postharvest handling method should be evaluated
as to its potential impact on nutritional quality
before being recommended for use