Post harvest Management of Horticultural Crops (2+1)

Environmental factors

Factors responsible for deterioration of horticultural produce

II. Environmental factors

Following environmental factors are responsible for deterioration
1. Temperature
2. Relative humidity
3. Atmospheric gas compositions
4. Ethylene
5. Light
6. Other factors


1. Temperature

Environmental temperature plays very major role in deterioration of produce.

• Every increase of 100C temperature above optimum increases the deterioration by two times
• Exposure to undesirable temperature results in many physiological disorders like; freezing injury, chilling injury and heat injury etc.
• Temperature influence growth rate of fungal spores and other pathogens.
• It affects the respiration and transpiration rate of produce.

2. Relative humidity

The rate of loss of water from fruit, vegetables and flowers depends upon the vapor pressure deficit between the surrounding ambient air, which is influenced by temperature and relative humidity. The rate of deterioration is a combined factor of temperature and relative humidity and affects the produce in following manner:

• Low Temperature & High Relative Humidity -- Low deterioration
• Low Temperature & Low Relative Humidity -- Moderate deterioration
• High Temperature & High Relative Humidity -- High deterioration
• High Temperature & Low Humidity -- Very high deterioration
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3. Atmospheric gas composition

Build up of undesirably high carbon dioxide and very low levels of oxygen in the storage facility can lead to many physiological disorders leading to spoilage. Eg. Hollow heart disease in potato is due to faulty oxygen balance in storage or during transportation. Exposure of fresh fruits and vegetable to O2 levels below the tolerance limits or to CO2 levels above their tolerance limits in storage rooms may increase anaerobic respiration and the consequent accumulation of ethanol and acetaldehyde, causing off-flavours. The other bad effects of unfavourable gas composition include irregular ripening of certain fruits, soft texture, lack of characteristic aroma, poor skin color development, etc.
Example: CA storage of Apples(0-10C with 1-2%CO2 and 2-3%O2, RH 90-95%) for 6-12 month.


4. Ethylene

Effect of ethylene on harvested horticulture commodities may be desirable or undesirable. On one hand ethylene can be used to promote faster and more uniform ripening of fruits. On other hand exposure to ethylene can deteriorate the quality of certain vegetables such as destruction of green colour in leafy and other vegetables, early senescence of flowers, bitterness in carrots, increased toughness, accelerated softening, discoloration and off-flavor, etc.


5. Light

Exposure of potatoes to light results in greening of the tuber due to formation of chlorophyll and solanine which is toxic to human on consumption.


6. Other factors

Various kinds of chemicals (eg. pesticides, growth regulators) applied to the commodities also contribute to deterioration. Many of the chemical constituents present in stored commodities spontaneously react causing loss of color, flavor, texture and nutritional value. Further there can also be accidental or deliberate contamination of food with harmful chemicals such as pesticides or lubricating oils.

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