Storage
Potatoes are stored to ensure:
- a more regular supply of potatoes for the market and for processing (consumption potatoes)
- that the producer to obtains higher market prices (seed- and consumption)
- that potato seed in a good physiological stage is available at the required planting time (seed potatoes)
For each case has to be determined whether for a more regular supply either an 1) adaptation of the growing periods or an 2) investment in storage facilities is the best solution.
Storage life
The storage life is the length of the period that potatoes can be stored and still be suitable to use as either consumption or seed.
Storage life is influenced by 1) storage temperature, use of 2) diffuse light and application of 3) sprout inhibitors.
STORAGE LIFE
Storage losses and physiological/chemical changes
Losses are unavoidable during storage and changes in physiological conditions as well as chemical changes will occur.
TUBER PHYSIOLOGY------DORMANCY-SPROUT GROWTH
Storage conditions
Storage conditions should be such that :
- losses caused by evaporation, respiration, sprouting, infection by micro-organisms (fungi
and bacteria) and insects are kept at a minimum
- tubers are brought up to or kept at the right physiological stage
- the chemical composition of the tubers is maintained at or brought up to the desired quality
Technical principles used in storage
Main principles used in storage are: insulation, cooling, ventilation, drying.
Insulation: Clamps are covered with straw and/or soil, etc. to protect tubers from adverse weather conditions: e.g. rain, light, solar radiation, frost.
For long-term storage in areas with a relatively large difference between the outside ambient air temperature and desired storage temperature, the stores have insulated walls and are cooled using refrigeration or outside air cooling.
Cooling: Heat is removed from the store and potatoes by: natural ventilation, forced ventilation with outside cool air or refrigeration.
Ventilation and drying: Potato stacks are ventilated by convective ventilation or forced ventilation.
With drying and ventilation the spreading of diseases in the store is reduced.
With convective ventilation the air velocity in the stack is low. Temperature difference is high in large stacks and drying of potatoes is relatively slow.
Forced ventilation is more efficient than convective ventilation since with forced ventilation (fans and duct system) the velocity of the air that passes through a potato stack is high.
As a consequence the temperature differences in the stack are relatively small and the potatoes can be dried quickly.
VENTILATION AND STORAGE METHODS
Storage methods
Main storage systems are:natural ventilated stores, clamps, diffuse light stores, cold stores.