|Small Scale Processing of Oilfruits and Oilseeds (GTZ, 1989, 100 p.)|
|2. Target Groups and Technologies|
|2.1 Family level|
(see Flowsheet 1)
The semi-wild palms are mainly of the dura" variety. The aura fruit contains large nuts with a thick outer shell. Around the nut is a relatively thin layer of oilcontaining fruit pulp.
Flowsheet 1 Traditional Process for Oil Palm Fruit
Women search for fruits that have dropped out of the bunches from the trees or buy loose fruit at the market. Women do not climb palms and thus can only obtain bunches of fruit that have been cut by the men. Women can pay men to climb the trees and cut the bunches. Bunches have to be stripped to obtain the fruit.
The fruit can be more easily separated from the bunches after fermentation in a heap for 3-4 days. To facilitate the separation the bunches can be cut in small clusters before fermentation.
The fruit is cooked and subsequently pounded using mortar and pestle. When larger quantities are to be processed, in some areas, the fruit is pounded using a halved drum and a large number of pestles or the fruit is mashed by trampling with the feet in a pit. Men can assist with the stripping of the bunches and the mashing of the fruit. After crushing by pounding or trampling, the mass of fruit pulp and nuts is mixed with excess water. The nuts are washed free from pulp and are allowed to settle to the bottom. The fibres are then thoroughly washed with water and finally pressed out by hand to remove all oil and oil-containing cell material.
In some areas just the floating cream is collected, whereas in others all the liquid that remains after removal of the nuts is taken. This mass is transferred to a drum and boiled for a few hours. The palm oil at the top is skimmed off and finally purified and dried by heating in a separate pot. The remaining sludge is sometimes concentrated by boiling and used for food.
The nuts are spread on the ground and dried in the sun, after which they are cracked to obtain the kernel, traditionally by tapping between stones. The fibre is also dried and used as a combustible.
The required time reported for processing one drum (44 gallons or 2001), containing around 150 kg of palmfruit, is on the average 24 and 32 man working hours respectively for Benin and Gambia.
Oil recovery out of a drum varies between 9 kg for aura' oil palm fruit in Gambia, about 15 kg for aura fruit in other countries and as much as 20 kg for a aura! tenera (improved variety) mixture in Cameroon.
Traditionally, the fruit could be left to ferment for days, making the processing quite easy. However, this oil contains a high percentage of free fatty acids and has a sharp taste. It is therefore known as hard" oil.
Possibilities for improvement
In principle the traditional method for processing oil palm fruit is based on the separation of the oil-containing cell material from the nuts and the fibre followed by the extraction of the oil from the cells by prolonged cooking. This process has a limited oil recovery and requires much water and energy.
These drawbacks can only be overcome by changing to a process that uses practically no water but demands thorough preparation of the fruit, before the oil can be extracted with a hand press.
Since such a system requires much more investment than the traditional process, it is not a feasible proposition at the family level. Only at village level can the investments be justified either in the form of a service system, to be used by processors against a fee' or as an asset of a specialized informal or formal co-operative. Details of the processes are given under 2.2.1.