Abstract
Tomatoes (Lycopersicon esculentum cv. Santa) are climacteric fruit that continue
to ripen after harvest. Once the fruit are separated from the plant, the
physiological reactions that control the ripening process are altered, so that
tomato quality is altered. The earlier the stage of ripening at harvest, the larger
the discrepancy between the tomatoes left to ripen on the plant and those
harvested while still unripe. Quality is lost as the tomatoes lose moisture,
firmness, nutrients and stored carbohydrates. Other aspects such as colour and
flavour development and cell wall modifications also affect the quality of unripe
harvested tomatoes. Environmental factors that affect the postharvest quality
include the temperature, humidity and atmospheric conditions in which the
tomatoes are stored. Hormonal manipulation (introducing or blocking ethylene)
also has an effect on the final fruit quality. This research project concentrated on
the changes that occur in quality during post harvest ripening. Comparisons
were made on how different post harvest treatments and storage protocols
influenced the quality and longevity of tomato fruit. The purpose of this study
was to determine storage conditions that would prolong the shelflife of tomatoes
so that they can be acceptable for consumption for up to 40 days after harvest.
The best results were obtained from tomatoes that had not completely turned red
at time of harvest. These tomatoes could maintain their acceptability best when
they were stored at 12°C under controlled atmosphere conditions. 1-MCP
treatment was also effective in limiting quality losses for up to a week after
harvest, and avoiding exposure to ethylene gas can also be recommended. Heat
treatment was not at all successful in improving the longevity of the fruit.
Prof. C.S. Whitehead