2.2.3 Processing technology seeds

Neem fruits can be processed in two different ways:

a) Wet processing on a small scale:

The fruit is depulped by hand, by rubbing and squeezing the pulp in water using sieves or hand-driven modified coffee depulpers. Modified coffee depulpers, however, have turned out to cause too much loss (damaged kernels and subsequent fungal infection).

The unripe fruits can be depulped after being stored for 4 - 5 days in the shade. After depulping, the seeds have to be washed in water, dried for 4 - 5 hours in the sun and then moved to the shade, if the sun is strong enough to risk lowering the azadirachtin content of the kernels. The time required for drying depends on the climatic conditions. The seeds should have a moisture content of less than 7%. A higher moisture content will lead to fungal contamination and subsequently to a reduced azadirachtin content.

b) Wet processing in a depulping plant:

Here the fruits are delivered to a processing plant. The process is more or less the same as on a small scale. The fruits are sorted into ripe and unripe ones. The ripe ones are depulped in depulping rollers (cylinders) with a capacity of 300-500 fruits/hour.

The depulped seeds will be either washed manually or by mill electric washing machines to be eventually dried on drying sieves.

Usually the limiting factor for wet processing units is the lack of sites covered by a roof for ripening the unripe fruits and for drying the seeds. A problem encountered by both small-scale and semi-industrial processing is the lack of adequate drying units for the seeds, to avoid fungal contamination and reduce the moisture content.

In arid areas without water the seeds are cleaned by rubbing them in sand.

For storage, the seeds should be disinfected by some means, e.g. calcium hypochlorite, and dried in the sun or by heating devices to achieve a moisture content lower than 7%. The seeds should be stored in a shady and airy place. This is one of the main problems, especially on village level, due the lack of space in the huts of the poor collectors.

There has been good experience with entrepreneurs sponsoring drying and storing facilities to gain better quality seeds and build a close relationship between the collectors and themselves. This includes receiving credit to process the inferior quality seeds into neem oil for the village.