The majority of factors that reduce the storage life of plantain and banana occur after harvest. Postharvest handling includes field storage, grading, packing, transport, and marketing.
Improved practices during postharvest handling can greatly increase storage life. This is illustrated by comparing traditional postharvest handling of plantain and banana with the highly organized postharvest handling of dessert bananas for export.
Traditional postharvest handling. In West Africa, production of plantain and banana is mainly small scale, and farmers have no specialized harvesting equipment. Fruits are often moved in bulk from farms to towns for sale, which can be several hundred kilometers away. Vehicles used for transport include trucks, the tops of buses, and bicycles.
Plantains and bananas may be transported as whole bunches, as hands, as clusters, or as individual fingers. They may be stacked up to 2 m deep to fill all available space. In some cases, plantains and bananas are cushioned with leaves or stored in jute sacks, but often there is no protection against damage.
Dehanding (separating bunches into hands) and transporting fruit in sacks reduces damage during transport. However, dehanding and packing are labor- and time-intensive processes. Therefore, there may be a trade-off between the advantages of dehanding and the time and skill available.
Harvesting, dehanding, and loading plantain and banana into vehicles may take 2-3 days. Journey time to town may be a further 3 days. Therefore, plantain and banana may be exposed to ambient conditions, with no protection from physical damage, dehydration, and high temperatures, for up to 6 days. Despite this, most of the produce reaches the market green and without significant damage. It is estimated that losses in traditional West African systems are less than 10%.
Improved postharvest handling. For transport to more distant markets, often thousands of kilometers away, a highly organized postharvest system has been developed for dessert bananas.
The bananas are harvested at a specific maturity, relating to the number of days from flowering, the angularity of the fingers in cross section, the size of fingers, and distance to market. Skilled teams harvest the bananas, using specialized equipment to cut stems and support cut bunches. Where flat land allows, wire and pole systems suspend and transport the bunches from the field to the packing shed.
The bananas are then separated into hands. The hands are washed in a solution (2% alum, 20% chlorine) to sterilize them, and to prevent latex from cut fruit staining the peel, and then treated with fungicide.
The hands are then packed into fiberboard boxes. The boxes may be lined with polythene, or the hands may be sealed in polythene bags. The boxes are stowed at a specific stack height and configuration in refrigerated stores or transport containers. At the destination countries, the unripe bananas are distributed to ripening depots, where the ripening process is initiated with ethylene gas. Bananas are then distributed to retail outlets/markets. The storage life of bananas, using these techniques, is 4-8 weeks.
|Objectives, Study materials, Practicals|
|1||Storing plantain and banana|
|2||Improving storage life|
|3||Temperature, humidity and ventilation|
|5||Treatment of fruit|
|6||Improving postharvest handling|
|8||Suggestions for trainers|