It is generally agreed that the Oil Palm(Elaeisguineensis)originated in the tropical rain forest region of West Africa.The main belt runs through the southern latitudes of Cameroon, Côted’Ivoire, Ghana, Liberia, Nigeria, Sierra Leone, Togo and into theequatorial region of Angola and the Congo. Processing oil palm fruits for edibleoil has been practiced in Africa for thousands of years, and the oil produced,highly coloured and flavoured, is an essential ingredient in much of thetraditional West African cuisine. The traditional process is simple, but tediousand inefficient.
During the 14th to 17th centuries some palm fruits were takento the Americas and from there to the Far East. The plant appears to havethrived better in the Far East, thus providing the largest commercial productionof an economic crop far removed from its centre of origin.
Palm oil is rich in carotenoids, (pigments found in plants andanimals) from which it derives its deep red colour, and the major component ofits glycerides is the saturated fatty acid palmitic; hence it is a viscoussemi-solid, even at tropical ambients, and a solid fat in temperateclimates.
Because of its economic importance as an high-yielding sourceof edible and technical oils, the oil palm is now grown as a plantation crop inmost countries with high rainfall (minimum 1 600 mm/yr) in tropical climateswithin 10° of the equator. The palm bears its fruit in bunches (Fig.1)varying in weight from 10 to 40 kg. The individual fruit, (Fig. 2) ranging from6 to 20 gm, are made up of an outer skin (the exocarp), a pulp (mesocarp)containing the palm oil in a fibrous matrix; a central nut consisting of a shell(endocarp); and the kernel, which itself contains an oil, quite different topalm oil, resembling coconut oil.
Diagram 1: Structure of the palmfruit
Fig. 1. Fresh fruit bunch(ffb)
Fig. 2 Fresh fruit (on the leftis a cut fruit)
The wild oil palm groves of Central and West Africa consistsmainly of a thick-shelled variety with a thin mesocarp, called Dura. Breedingwork, particularly crosses between Dura and a shell-less variety (Pisifera),have led to the development of a hybrid with a much thicker mesocarp and athinner shell, termed Tenera. All breeding and planting programs now use thislatter type, the fruits of which have a much higher content of palm oil than thenative Dura.
The extensive development of oil palm industries in manycountries in the tropics has been motivated by its extremely high potentialproductivity. The oil palm gives the highest yield of oil per unit area comparedto any other crop and produces two distinct oils - palm oil and palm kernel oil- both of which are important in world trade.
Modern high-yielding varieties developed by breeding programs,under ideal climatic conditions and good management, are capable of producing inexcess of 20 tonnes of bunches/ha/yr, with palm oil in bunch content of 25percent. This is equivalent to a yield of 5 tonnes oil/ha/yr (excluding the palmkernel oil), which far outstrips any other source of edible oil.
Ideal composition of palm fruitbunch
Bunch weight | 23-27 kg |
Fruit/bunch | 60-65 % |
Oil/bunch | 21-23 % |
Kernel/bunch | 5-7 % |
Mesocarp/bunch | 44-46 % |
Mesocarp/fruit | 71-76 % |
Kernel/fruit | 21-22 |
Shell/fruit | 10-11 |
However, such high yields are rarely achieved in practicebecause climatic conditions are usually less than ideal. Rainfall is erratic inCentral and West Africa and hence the tree suffer water-related stresses. Themanagement of costly inputs of labour, imported fertilizers, pesticides andharvesting machinery, is also a difficulty that hampers the yield ofplantations.
International trade in palm oil began at the turn of thenineteenth century, while that of palm kernels developed only after 1832. Palmoil became the principal cargo for slave ships after abolition of the slavetrade. The establishment of trade in palm oil from West Africa was mainly theresult of the Industrial Revolution in Europe. As people in Europe began to takesanitation and hygiene seriously, demand for soap increased, resulting in thedemand for vegetable oil suitable for soap manufacture and other technical uses.Tinplating required technical oil for which palm oil was found suitable. In theearly 1870s exports of palm oil from the Niger Delta were 25 000 to 30 000tonnes per annum and by 1911 the British West African territories exported 87000 tonnes.
The export of palm kernels also began in 1832 and by 1911British West Africa alone exported 157 000 tonnes of which about 75 percent camefrom Nigeria. Nigeria was the largest exporter until 1934 when the country wassurpassed by Malaysia. Africa led the world in production and export of palm oilthroughout the first half of the 20th century, led by Nigeria and Zaire. By1966, however, Malaysia and Indonesia had surpassed Africa’s total palm oilproduction. According toOil Palm Review, published by the TropicalDevelopment and Research Institute in the United Kingdom, over 3 million tonnesof palm oil was produced by Malaysia alone in 1983, compared with a total ofabout 1.3 million tonnes of African production.
This publication does not intend to discuss the factorsleading to the spectacular performance of Indonesia and Malaysia. However inthese countries solid research and development has been undertaken backed by aconscious desire to implement research findings. The plantation developmentculture acquired from long cultivation and processing of latex rubber was a goodfoundation on which to introduce the large-scale plantation cultivation of palmoil. Mastery of technology and rapid mechanisation, together with governmentsupport to the industry as a systematic and strategic industrial developmentpolicy, facilitated private sector investment in this sector. These factors aswell as many others have all played a part in the development of the FarEast’s rise to prominence in the oil palm industry.
The primary unit of production of the palm oil industry is thefarm where the oil palm tree is cultivated to produce palm fruits. There arealso wild groves of oil palm. The farm units are of different sizes and may beclassified as small, medium, and large-scale estates.
The wild groves, as the name implies, grow untended in theforest. They are found in clusters and are mainly the result of natural seeddispersal. Dura, the main variety found in the groves, for decades has been thesource of palm oil - well before modern methods of oil palm cultivation wereintroduced to Africa in the second quarter of the 20th century.
The other varieties are Pisifera and Tenera, which is a hybridvariety obtained by crossing Dura and Pisifera. The Dura has a large nut with athick shell and thin mesocarp. The Pisifera is a small fruit with no shell. Bycrossing the Dura with Pisifera a fruit is obtained with a thick mesocarpcontaining much more oil and fat (chemically saturated oil) than either of itsparents. The Tenera nut is small and is easily shelled to release the palmkernel. The Tenera palm kernel is smaller than the Dura kernel although theTenera bunch is much larger than Dura. In all, the Tenera is a much bettervariety for industrial and economic purposes.
Unfortunately, traditional farmers in Africa have not embracedthe Tenera because consumers complained that the palm oil produced from thevariety was too fatty. This means that when the oil cools to ambient temperatureit ‘goes to sleep’ or solidifies instead of remaining fluid and red.The oil did not have the right taste as oil or as a soup base. Extensionofficers failed to position the Tenera as high-yielding industrial purpose oil,as opposed to oil for home cooking. The negative perception of Tenera led to itsslow adoption and the failure of Africa to maintain its lead in palm oilproduction.
Plantation farming is a new phenomenon to West Africanculture. In most parts of Africa the farm culture is basically subsistence. Thefamily cultivates a small plot for their food needs and interplant tree crops.After three years or more the tree crop takes over the plot and the farmer movesto another. The new plot may be acquired from the Chief in a location farremoved from the old plot. Farm-holdings are therefore small and scattered. Theland tenure system does not permit large-scale farming unless the governmentsteps in to acquire the land for public use. Thus it is difficult to think ofone family owning a large contiguous estate suitable for plantationfarming.
A small-scale palm oil farm may cover 7.5 hectares. Thefarm’s production of fruits may be processed by the farmer, using thetraditional method of palm oil extraction, or sold to other processors. Duringthe lean season the farmer sells to the small-scale processors at prices higherthan those offered to the larger mills. The small-scale farms are normally wellmaintained even though they may not adopt modern agronomic practices such asapplication of fertilizer, cover cropping, etc. to improve soil fertility andyields.
The medium-scale farm ranges from 10 to 500 hectares. Thistype of farm normally uses modern agronomic practices such as plant spacing,cover cropping, fertilization, ring weeding, pruning, etc. Some farmers in thiscategory own processing facilities and therefore use their own output as well asbuying from neighbours. Those who do not own mills face marketing problemsduring the peak season when fruit is abundant and processors do not have toforage for raw materials.
Because the fruits are perishable and lose weight onceharvested, farmers need prompt payment and evacuation of their fruits. If theroads are impassable they may suffer great loss of produce and income making itdifficult for these farmers to finance their operations. As a result a number offarmers in this category are unable to adequately maintain their farms,resulting in decreased output from year to year.
Large-scale farms cover an area in excess of 500 hectares.These are state owned enterprises which were established to meet the internalconsumption needs of the country and provide a surplus for export. The estatesare well run and maintained. They employ the best farming techniques and employhighly skilled professionals to work their operations. Unfortunately they arealways considered intruders in the communities where they operate, simplybecause they employ people who are not natives of the immediate catchmentarea.
Most estates are being privatised or sold to private interestsin an effort to wean the respective governments from directly engaging incompetitive businesses. Most estates had nucleus farms with out-growers andprivate smallholders supplying raw palm fruit to the central processing factory.The processing facilities were generally in the large-scale category.
Because of privatization exercises some large-scale processingoperations have closed, leaving plantation output to be sold to small-scaleprocessors. It is not unusual today to find many small-scale processingoperations exploiting the splitting up of a plantation estate. The Republic ofBenin, Cameroon and Ghana abound with examples of this type of take-over bysmall-scale operators.
The general principles of preservation include:
· destruction of enzymes (a complex organic substancewhich in solution produces fermentation and chemical changes in other substancesapparently without undergoing any change itself) in the raw material andcontaminating micro-organisms by heat (sterilization) duringprocessing;
· elimination of as much wateras possible from the oil to prevent microbial growth (bacterial activity, ordisease-causing germs) during storage. The oil therefore has a long shelf lifedue to its low moisture content.
· Proper packaging and storageof the extracted oil to slow down chemical deterioration (rancidity).
The method used to extract vegetable oil depends on the typeof raw material available. Raw materials may be grouped according to the part ofthe plant that contains the fat or oil (seed, bean, nut or fruit). The maindifference in raw materials is the moisture content. Raw materials with lowmoisture content include seeds and beans and some nuts, which are dried onharvest. Palm fruit, olive fruits and some coconuts are processed wet.
Only seeds, nuts and fruits that contain considerable amountsof edible oil are used for small-scale oil extraction. Other types (for examplemaize) may contain edible oil, but the quantities are too small for economicprocessing on a small-scale. However, not all oil-rich seeds and fruits haveedible oil; some contain toxins (poisons, usually of bacterial origin) or haveunpleasant flavours; these are used only for varnishes, paints, etc. Others,(for example castor oil) need very careful processing to make them safe for useas medicines. These are not suitable for small-scale processing.
Palm fruit contains about 56 percent oil (25 percent on afresh fruit bunch basis) which is edible with no known toxins. It is thussuitable for small-scale processing.
