Post harvest Management of Horticultural Crops (2+1)

Principles of storage

1. Control of respiration
Respiration is a breakdown process; hence storage method should provide a means to minimize this metabolic process. Cold storage, atmospheric modification, low pressure storage are the methods used based on this principle. The heat generated during respiration, usually know as respiratory heat /heat of respiration, accumulates in the centre of the storage. The rate of respiration of stored produce increases if this heat is not removed from the storage room. So, proper ventilation will help in removing this heat thereby reducing the respiration rate. Reducing respiration rate will also help in delaying the ripening process in some fruits and vegetables thereby extending the storage life

2. Control of transpiration
Fresh produce continues to lose water even after harvest resulting in wilting or shriveling of produce. A 5% loss of moisture is enough to make the produce shrivel making it unattractive for marketing. Relative humidity and temperature are the important factors that influence the loss of moisture from fresh produce. Water loss will also be high with increase in storage temperature. Fresh produce transpire more at high temperatures and low humidity. Hence, this process can be controlled by storing the produce at low temperatures and high relative humidity.

3. Prolonging the Dormancy period/Control of sprouting and rooting
Some root and tuber type vegetables after harvest enter into a resting phenomenon know as Dormancy. During this period, sprouting and rooting of these crops does not occur. However, under favourable conditions these crops re-grow resulting in sprouting and rooting. Consumers do not prefer the sprouted or rooted vegetables for buying. Sprouting also makes the produce to lose moisture quickly, shrivel and become prone to microbial infection. Hence, prolonging the dormant period by creating unfavorable conditions is the principle for extending the storage life of this type of produce.

4. Control of spoilage
Fresh produce have high moisture and readily available nutrient and therefore readily attacked by microorganisms. Favourable conditions like warm temperature and high humid condition in the storage room enhance the growth of these micro-organisms and increase the spoilage. Hence, storage methods should aim at retarding or control of the growth of these spoilage causing micro-organisms.