Post Harvest Management of Horticultural Crops

Cold stores

Solar driven cold stores
In tropical countries, solar energy is utilized in refrigeration cycle. In Sudan, such stores have been developed having single stage ammonia/water absorption refrigerator with 13 kw peak cooling power and were designed to keep 10 tonnes of agricultural products (volume 50 m2) at a minimum temperature of 5°C, as tested on bananas. This system is however costly when compared to conventional cold stores operated by electricity.

Jacketed storages
These are double walled storages where heat conducted through the floor, walls and ceiling is intercepted and removed by the refrigeration system before it reaches the storage space. The walls, ceiling and floor act as cooling surfaces. Humidity close to 100% is maintained. These jacketed storages built in Canada are 10% more costly than conventional storages.

Low Pressure Storage / Hypobaric Storage
Fruits can be stored under low pressure of 0.2 – 0.5 atmospheric pressure and temperature of 15 - 240C under airtight chamber. Pressure is reduced by sucking air and creating vacuum.
Mechanism

• Reduced O2 supply slows down the respiration. When presser reduced from the 1 atm to 0.1atm the effective O2 concentration reduced from 21 to 2.1%.
• Eg. in apples, low pressure reduces level of ethylene to 0.01ppm which does not stimulate ripening.
• Released ethylene is removed out of storage.
• Volatiles such as CO2, acetaldehyde, acetic acid, ester etc. are removed/reduced.