Chemical Reactions After Harvest

After harvesting, the chemical reactions in fruits and vegetables continue.

Plants are no longer supplied with water and nutrients from the soil, so once harvested they are living on reserves. In some plants, some parts continue to grow by feeding on other parts. For example, the leafy tops of carrots, beets and radishes, and the inner shoots of celery.

Chemical reactions which are the opposite of photosynthesis occur. Oxygen combines with the plant sugars to produce heat, carbon dioxide and water vapour. To keep fruits and vegetables fresh the heat of this respiratory reaction must be removed as quickly as possible by refrigeration and ventilation. Even small rises in temperature can reduce shelf life.

The warmer the temperature of the vegetable, the faster it dies. Lowering the temperature is the most effective way to slow ageing. As the living cells in the plants die, fungi grow and break them down. This is nature’s way of making dead plants useful to other living plants in the form of compost.

References

Debney, H.G. (1980). Handling and Storage Practices for Fresh Fruit and Vegetables: Product Manual. South Yarra, Vic.:Australian United Fresh Fruit and Vegetable Association.

Tomkins, B. (1995). Agriculture Notes: Storage Life of Vegetables [online]. Knoxfield: Victorian Department of Primary Industries.

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