2.1.1 Oil palm fruit
(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"
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