II.E.3. - Palm Oil
oil palm (Elaeis guineensis) is a native of West Africa.
It flourishes in the humid tropics in groves of varying density,
mainly in the coastal belt between 10 degrees north latitude and
10 degrees south latitude. It is also found up to 20 degrees south
latitude in Central and East Africa and Madagascar in isolated
localities with a suitable rainfall. It grows on relatively open
ground and, therefore, originally spread along the banks of rivers
and later on land cleared by humans for long-fallow cultivation
(Hartley 1988: 57).
palm fruit develops in dense bunches weighing 10 kilograms (kg)
or more and containing more than a thousand individual fruits
similar in size to a small plum. Palm oil is obtained from the
flesh of the fruit and probably formed part of the food supply
of the indigenous populations long before recorded history. It
may also have been traded overland, since archaeological evidence
indicates that palm oil was most likely available in ancient Egypt.
The excavation of an early tomb at Abydos, dated to 3000 B.C.,
yielded "a mass of several Kilograms still in the shape of
the vessel which contained it" (Friedel 1897).
sample of the tomb material was submitted to careful chemical
analysis and found to consist mainly of palmitic acid, glycerol
in the combined and free state, and a mixture of azelaic and pimelic
acids. The latter compounds are normal oxidation products of fatty
acids, and the analyst concluded that the original material was
probably palm oil, partly hydrolyzed and oxidized during its long
storage. In view of the rather large quantity found, the oil was
probably intended for dietary purposes rather than as an unguent.
few written records of the local food use of a palm oil (presumably
from Elaeis guineensis) are available in accounts of European
travelers to West Africa from the middle of the fifteenth century.
Red palm oil later became an important item in the provisioning
trade supplying the caravans and ships of the Atlantic slave trade,
and it still remains a popular foodstuff among people of African
descent in the Bahia region of Brazil (Northrup 1978: 17886;
Hartley 1988: 13; R. Lago, personal communication, 1993).
British Industrial Revolution created a demand for palm oil for
candle making and as a lubricant for machinery. In the early nineteenth
century, West African farmers began to supply a modest export
trade, as well as producing palm oil for their own food needs.
After 1900, European-run plantations were established in Central
Africa and Southeast Asia, and the world trade in palm oil continued
to grow slowly, reaching a level of 250,000 tonnes (metric tons)
per annum by 1930 (Empire Marketing Board 1932: 11723; Hartley
1988: 823; Lynn 1989: 22731).
the invention of the hydrogenation process for oils and fats in
1902 created the possibility of Western employment of palm products
as, for example, in the making of margarine. Yet hydrogenation
was more useful for liquid oils like groundnut, palm kernel, and
coconut oils than for palm oil. After World War II, further improvements
in palm oil refining technology and transport methods made it
possible to use largely unhydrogenated palm oil in Western food
products (Lim 1967: 1302; Martin 1988: 458).
rapid expansion of the palm oil export trade followed, accompanied
by a marked growth in the plantation sector of production. Between
1962 and 1982, world exports of palm oil rose from about 500,000
to 2,400,000 million tonnes per annum, and Malaysia emerged as
the worlds largest producer, accounting for 56 percent of
world production and 85 percent of world exports of palm oil in
1982. Expanded production in Malaysia was achieved mainly by the
privately owned estate sector, which increased its oil palm holdings
more than tenfold in the 1960s and 1970s; and by the Federal Land
Development Authority (FELDA), whose large-scale schemes organized
oil production along plantation lines, although ownership was
vested in the workforce of "smallholders" (Khera 1976:
1835; Moll 1987: 14062).
1990, world production had reached nearly 11,000,000 tonnes per
annum, with a worldwide trade of 8,500,000 tonnes (Mielke 1991:
110). Although red palm oil is still used in soups and baked dishes
in West Africa, elsewhere in the world, palm oil is eaten mainly
in a highly refined form. Its food uses vary from the vanaspati
and ghee of India to the margarine, cooking oils, and biscuits
of Europe and the United States.
Palm: Wild and Planted
Africa is the classic region of smallholder production, both of
food and export crops. The oil palm, which has been both, flourishes
in natural association with yam and cassava cultivation throughout
the wetter parts of the region. In eastern Nigeria, which C. W.
S. Hartley (1988: 7, 16) called "the greatest grove area
of Africa," densities of 200 palms per hectare (ha) were
common in the late 1940s, and densities of more than 300 palms
per hectare were not unknown.
palms were typically self-seeded and tended (to varying degrees)
by local farmers. Farther west, in the kingdom of Dahomey and
in settlements established by the Krobo people near Accra, some
deliberate plantings may have been made as the palm oil export
trade developed from the 1830s (Manning 1982; Wilson 1991). However,
as J. Reid (1986: 211) has noted, the word plantation was
often used by contemporary European observers to mean a food farm
on which oil palms happened to be growing. Moreover, although
in Dahomey descriptions exist of seedlings being transplanted
from the bush onto areas cleared for farming by slaves, this does
not mean that the practice was universal. In any event, palm oil
exports from Dahomey were much smaller than from the Niger Delta,
where oil palms were planted deliberately in swampy regions outside
their natural habitat, but where the bulk of production was carried
out using natural groves. In the 1840s, Dahomey and the Niger
Delta exported approximately 1,000 and 13,000 tonnes per annum
respectively; by the 1880s these totals had risen to 5,000 and
20,000 (Manning 1982: 352; Reid 1986: 158; Martin 1988: 289;
Lynn 1989: 241).
in the late nineteenth century, a number of experimental oil palm
plantations were created by Europeans in West and west-central
Africa. One of the earliest was founded in Gabon in 1870 by Roman
Catholic missionaries (E. J. Mulder, personal communication, 1968).
But like many of the other nineteenth-century plantations in West
Africa, these ventures were unsuccessful. By comparison with African
smallholders, European planters were highly specialized and vulnerable
to the marked trading fluctuations of the late nineteenth century.
Many also lacked capital but committed themselves to long-term
investments of a type that African farmers sensibly rejected.
the case of palm oil, money was spent paying laborers to produce,
plant, and tend seedlings, often on marginal land, in regions
where natural groves already contained more palms than local farmers
could spare the time to harvest (Hopkins 1973: 21214; Martin
when in 1907 William Lever sought large-scale land concessions
in the British West African colonies in order to produce palm
oil for his Lancashire soap mills, the Colonial Office was reluctant
to help him. In a region characterized by small, fragmented, and
often communally owned farms, it was felt that Levers scheme
would be hard to administer, politically risky, and commercially
unsound. Lever was left to pursue his dreams in the Belgian Congo,
where the existing levels of both trade and population were far
lower and where the colonial administration welcomed European
enterprise (Hancock 1942: 188200; Wilson 1954: 15967).
the Lever debate, the West African palm oil industry remained
in the smallholders hands. Few other entrepreneurs came
forward to press the case for plantations, although a number of
state-run estates were established under French influence in the
Ivory Coast after 1960. By 1981 these estates covered a total
of 52,000 ha, with a further 33,000 ha planted with oil palms
in the surrounding villages (Hartley 1988: 31).
even this development was relatively modest in scale, as shown
in unpublished data from Nigeria, West Africas largest producer
of palm oil. The area of wild palm groves, only partly harvested,
was estimated at 2,400,000 ha, whereas there were 72,000 ha of
estate plantations and another 97,000 ha of smallholder plantations.
Estate plantations, which require large consolidated areas, are
still difficult to create in Nigeria because the oil palmgrowing
regions are densely populated and the complex traditional land
holding system has been carefully preserved. Elsewhere in West
Africa, population densities are lower, but the problems of obtaining
labor to sustain plantation developments are correspondingly greater.
the late nineteenth century, both the German colonizers of Kamerun
and the Belgian rulers of the Congo were keenly interested in
applying European farming and processing techniques to the palm
oil industry (Laurent 191213; Rudin 1938; Jewsiewicki 1983).
But German botanical and mechanical trials were cut short by World
War I, following which the German territories in Africa were divided
between the French and the British.
the Congo, however, Levers initial land- and produce-buying
concessions (granted in 1911) proved to be the foundation for
a long process of experimentation, which eventually revolutionized
the palm oil industry worldwide. New planting materials led to
dramatic increases in yields, thus cutting the cost of production;
and improved machinery led to high oil quality at a competitive
price. Alongside developments in European and American food-processing
techniques, the Congo innovations paved the way for the entry
of palm oil into Western diets.
was originally more interested in setting up mills than plantations
in the Congo, but his initial investments brought heavy losses
(Fieldhouse 1978: 5079). The fruit supply from wild trees
proved hard to control, both in the amount brought to the mill
and in its quality upon arrival. Overripe or bruised palm fruit
made for highly acidic, low-quality oil, whereas unripe bunches
gave low yields. Yet Lever Brothers (and its successor Unilever
after 1929) was unwilling to incur the heavy initial costs of
planting trees unless planting materials were improved to reduce
the running costs. The Germans in Kamerun had identified an exceptionally
thin-shelled palm fruit with a high oil content as early as 1902
(Hartley 1988: 50). But their "lisombe" palm, later
to become known as the Tenera type, was found only rarely in the
wild and failed to breed true.
a renewed drive to encourage European investment in their colony
and, in particular, in oil palm plantations, the Belgians began
in 1922 to investigate this German discovery. An experimental
plantation of Tenera palms was created at the Yangambi research
station in the Congo, and in the 1930s these palms were subjected
to a three-year testing program by M. Beirnaert. Meanwhile, private
Tenera plantings had been made by Unilever and its subsidiary,
the United Africa Company, in the British Cameroons and in the
Belgian Congo itself (Courade 1977; Fieldhouse 1978).
seed also found its way to Sumatra and Malaya in the 1920s, although
there, as in Central Africa, it failed to breed true. Beirnaerts
painstaking experiments finally showed why: The Tenera palm was
actually a hybrid of two other types, the thick-shelled Dura and
shell-less Pisifera, and when self-pollinated would produce 50
percent Tenera, 25 percent Dura and 25 percent Pisifera (Beirnaert
and Vanderweyen 1941).
discovery was published at the height of World War II, and it
was not until after 1945 that it could be turned to practical
use with the establishment of large-scale and long-term Tenera
breeding programs. It is ironic that the Congo was not the state
that gained the most. Its oil palm plantations did expand from
52,000 ha in 1938 to 93,000 in 1945 and 147,000 in 1958, with
a further 98,000 ha under smallholder cultivation by the end of
that period (Mulder, personal communication, 1968; Hartley 1988:
30). But political unrest following independence in 1960 led to
stagnation and decline in the industry.
however, the most important single investor in 1960 with 47,000
ha under oil palms, remained loyal to the newly independent country
of Zaire through two decades of intermittent losses and political
uncertainty. Thus, Unilever managers remained in place following
nationalization in 1975, and the company was allowed to take back
full control of the estates two years later (Fieldhouse 1978:
53045). But at a national level, the research effort was
decimated, and new planting was very limited after 1960, in marked
contrast to developments at the same time in Southeast Asia.
oil palm was first introduced to Southeast Asia in 1848, when
four seedlings, originating from West Africa, were planted in
the botanical gardens at Buitenzorg (now Bogor) in Java (Hartley
1988, 21). But this introduction did not lead to a plantation
industry for some time, although offspring of the palms were used
as ornamentals by tobacco planters.
1905 a Belgian agricultural engineer, Adrien Hallet, arrived in
Sumatra and noticed that its palms grew more quickly and bore
a richer fruit than counterparts in the Congo, where he had previously
worked. Just as the oil palms in southeastern Nigeria bore a fruit
with more oily pulp and a smaller kernel than their counterparts
farther west, so did the Deli Dura palms, descended from the four
Buitenzorg seedlings, hold a distinct advantage over the ordinary
Duras of West and Central Africa (Leplae 1939: 257; Martin
superiority probably reflected the optimal soils, rainfall, and
sunshine conditions of Southeast Asia, rather than any special
genetic quirks of the Buitenzorg palms. However, the fact that
all the Deli Duras were descended from so few parents meant that
the early planters could expect fairly uniform results (Rosenquist
1986). This lowered the risks associated with plantation cultivation,
an effect reinforced by the absence of the palms usual pests
and diseases in its new geographic setting.
relatively high yields and low risks from planting oil palms in
Southeast Asia helped the industry to grow quickly, following
the pioneering plantings of Hallet in Sumatra and of his friend
Henri Fauconnier in Malaya in the 1910s. By 1919 more than 6,000
ha had been planted in Sumatra, rising to 32,000 in 1925, by which
time 3,400 ha had come under cultivation in Malaya. Over the next
five years, a further 17,000 ha were planted in Malaya, while
the Sumatran area doubled.
rapid expansion came not only because of growing confidence in
the oil palm but also because of the grave postwar problems of
the rubber industry. The oil palm was seen as a useful means of
diversification to avoid a dangerous dependence on rubber. The
pace of new planting slowed during the worldwide slump of the
1930s, but by 1938 Malaya had nearly 30,000 and Sumatra more than
90,000 ha under cultivation (Lim 1967: Appendix 5.2; Creutzberg
1975: Table 11; Hartley 1988: 21).
in Sumatra hung fire for some time after 1945, as shown in Table
II.E.3.1. Meanwhile, developments in Malaysia were more rapid,
especially after 1960, when the replanting of old rubber estates
with oil palms was stimulated by FELDAs smallholder schemes.
the same time, the Malaysian government and the estate sector
launched several systematic Tenera-breeding efforts, in which
high-yielding parents were selected and through which increasingly
productive planting materials were generated. The new trees not
only yielded more fruit but also produced a type of fruit that
was ideally suited to the new screw presses which, having been
tried out in the 1950s in the Belgian Congo, became widely used
in Malaysia from the mid-1960s. These innovative developments
have been described as "one of the worlds outstanding
agricultural achievements" (Anwar 1981). The land area involved
is shown in Table II.E.3.2.
distinct species of the oil palm, Elaeis oleifera (also
known as Elaeis melanococca), is indigenous to Latin America.
Since the late 1960s, plant breeders have begun to take an interest
in this variety because its oil has a high iodine value and unsaturated
fatty acid content, making it especially suitable for food use.
However, the fruit is often small, with a thin oil-yielding mesocarp
surrounding a large, thick-shelled kernel. Harvested bunches often
contain a low proportion of fruit of quite variable quality. Hence,
the plant has not been cultivated commercially, although it is
frequently found in riverside or swampy areas, and the oil is
used locally for cooking, soap boiling, and lamp fuel (Hartley
1988: 859, 6813).
guineensis seeds were introduced to Central America by the
United Fruit Company, which brought seeds from Sierra Leone to
Guatemala in 1920, and from Malaysia to Panama in 1926 and Honduras
in 1927. Other introductions from Java and the Belgian Congo followed,
but the first commercial planting of 250 ha took place only in
Guatemala in 1940. The United Fruit Companys main interest
was, traditionally, the production of bananas for export, but
large banana-producing areas were destroyed by Fusarium wilt,
and in consequence, oil palm and other crops were being tested
oil palm, however, proved vulnerable to disease in its new setting,
and difficulties were encountered in identifying suitable growing
conditions. Nonetheless, a successful development was founded
on the northern coastal plain of Honduras, and in addition to
developing plantations on its own land, the United Fruit Company
stimulated oil palm cultivation by neighboring smallholders, whose
fruit could then be processed in the company mills. Seed was also
supplied to other Latin American countries (Hartley 1988: 336;
D. L. Richardson, personal communication, 1993).
beginnings of commercial planting in Latin America are summarized
in Table II.E.3.3. By 1992 the total area planted to Elaeis
guineensis in Latin America had grown to 390,000 ha
still a small fraction of the area in Africa or Southeast Asia.
The distribution of plantings by country and sector is shown in
the early years of the twentieth century, palm oil was processed
only by traditional village methods, by which loose fruits were
collected from the ground or a few bunches were cut from the tree.
Beginning in the 1920s, however, the United Africa Company and
British colonial officials in Nigeria started experimenting with
steam cookers and hand presses designed to make production at
the village level more efficient in terms of labor use and oil
yield. Yet a lack of cash prevented most farmers from trying the
new machinery, with the exception of a few lucky recipients of
free samples or government subsidies in the 1940s (Martin 1988:
separate process of trial and error led to the development of
the sophisticated factories required to deal with the volume of
fruit produced on modern plantations and to produce oil of the
high and standardized quality that would appeal to Western food
processors. Such factories handle almost all the palm fruit of
Southeast Asia, whereas in West Africa and Latin America, processing
is carried out by a wide variety of methods, yielding oil for
local consumption and for industrial as well as edible uses in
the scale and sophistication of the process, the following main
steps are required:
of individual fruits from the bunch.
of the fruit flesh.
out of the oily liquid.
of the oil.
ripe, fresh fruit bunches (FFB) are cut from the palm. With young
trees this can be done from ground level. With older trees in
West Africa, harvesting is still often accomplished by a man climbing
the tree, secured to it by a loop of rope or other locally available
materials, such as rattan and raffia fiber (Vanderyst 1920). But
on plantations, a curved knife attached to a bamboo is used. After
cutting, most of the fruits are still firmly attached to the bunches,
which are divided into a few sections, heaped together, moistened,
and covered with leaves. Natural fermentation during two to three
days loosens the fruits so that they can be picked off the bunch
sections by hand.
this step, two major variants in the process are used to produce
two oils with different characteristics those of soft oil
and those of hard oil. The regions producing each type have changed
since Julius Lewkowitsch (1895: 429) identified Saltpond in present-day
Ghana as the cheapest source of hard oil, and Drewin on the Ivory
Coast as the best place to buy soft oil. But the basic methods
have changed little since they were first described by colonial
officials in the 1910s and 1920s (Laurent 191213; Gray 1922;
Faulkner and Lewis 1923; Martin 1988: 323).
soft oil production, the fruits are separated as soon as they
are loose enough and boiled with water for 4 hours to soften the
flesh, which is very fibrous. The cooked fruit is emptied into
a large container, which may be a pit lined with clay, an iron
drum, or a large wooden mortar. It is then reduced to a pulp with
pestles or by treading it under foot. The resulting mash may be
diluted with water, and the oil is skimmed off or squeezed out
of the fibrous mash by hand. In some instances, a sieve made of
palm fronds is used to retain the fibers. At this stage the liquid
product, which contains oil, water, and fruit fibers, is often
boiled up with additional water and skimmed again, although this
step is omitted in some cases. Finally, the oil is again heated
to boil out the residual water.
(1922: 546) also reported on the preparation of small quantities
of oil for kitchen use directly from freshly picked fruit, by
boiling the fruit and skimming the oil. Such oil had good keeping
properties and often a free fatty acid content below 2 percent;
but yield was very low, and not available for export.
the hard-oil process, the fruit is allowed to ferment for 3 or
more days longer than in the
soft-oil process, until the flesh is soft enough. It
is then pulped by treading underfoot in an old canoe or pounding
in a mortar. Oil is allowed to drain out for up to 3 days, then
water is added, and the mix is trodden again. Further oil rises
to the surface and is skimmed. The oil is boiled up with water
in another container and finished as described for soft oil.
two processes differ in some important respects. The prolonged
fermentation in the hard-oil process results in a much greater
enzymic breakdown of the neutral fat and, therefore, in a much
higher free fatty acid content. The yield obtained by this process
is also much lower. However, it has a substantial advantage in
that the labor and firewood requirements are also much lower.
Table II.E.3.5 summarizes these differences.
strong characteristic flavors developed during both of these processes,
as well as the naturally strong red color of the oil, are appreciated
by local cooks and visiting gourmets, but they present severe
limitations in the export markets. The high free fatty acid content
and solid consistency of hard oil limits its range of uses, making
it well suited to soap boiling but not to food processing. The
solid consistency of hard oil is not due directly to the free
fatty acids formed during the fermentation step but rather to
the diglycerides, the other fragments obtained when one fatty
acid is split from the neutral triglyceride molecule. M. Loncin
and B. Jacobsberg (1965) have demonstrated the formation of a
eutectic between triglycerides and diglycerides, resulting in
a minimum melting point and maximum softness at a diglyceride
content of 7 percent.
of the Small-Scale Process
the rapid twentieth-century growth in West African exports came
the introduction of simple machines to reduce labor requirements
and increase oil yield from a given quantity of fruit. Early machines,
before and after the 191418 war, as described by Hartley
(1988: 694703), included a cylinder fitted with manually
operated beaters, which was fed with softened fruit and hot water.
After "beating," an oil-water mixture was run off through
a sieve. Another system used a special cooker and a press as adjuncts
to the soft-oil process.
first device to become widely adopted, however, was a modified
wine and cider press: the Duchscher press. This consisted of a
cylindrical cage of wooden slats, held in place by iron hoops,
and a ram on a screw thread. The screw thread was turned manually
by means of long bars (in the manner of a ships capstan),
forcing the ram onto the pulped fruit. The exuding liquid was
collected in a trough surrounding the cage.
presses, but using a perforated cylindrical metal cage, are still
in use today, giving yields of 55 to 65 percent of the oil present.
A recent analysis of the needs for mechanization in the village
has concluded that this is still the most practical implement,
because it can be made and maintained locally and is inexpensive
by comparison with other presses (C. E. Williams, personal communication,
1981). However, farmers in Nigeria (which was once the worlds
largest exporter of palm oil) have, since the 1950s, been reluctant
to invest in this or other improvements because of the low producer
prices offered by the state-controlled marketing boards. It is
to be hoped that recent reforms of marketing structures in Nigeria
and elsewhere in Africa will encourage renewed innovation at the
village level (Martin 1988: 12636).
next development in pressing was the introduction in 1959 of the
hand-operated hydraulic press by Stork of Amsterdam. This was
capable of processing 600 to 1,000 pounds of fruit per hour and
could recover 80 percent of the oil present. The hydraulic mechanism
was later motorized.
different approach to mechanization brought forth the Colin expeller
(first patented in 1904), which in essence is similar to a domestic
mincer. It consists of a perforated cylindrical cage, fitted with
a spiral screw or "worm," which is turned manually through
a gear. Cooked fruit is fed to the worm through a hopper, and
the pressure developed as the worm pushes the fruit forward forces
oil out through the perforations. Spent fiber and kernels are
discharged at the end of the cage. The machine has a capacity
of 100 kg cooked fruit per hour, or 250 kg per hour if motorized.
The Colin expeller became popular after 1930, mainly in Cameroon.
Its limitations were a reduced efficiency with Dura fruit, which
forms the bulk of the wild oil palm crop; rapid wear of the screw;
and a relatively high cost. The principle of the expeller, however,
has been further developed into the screw press found in all modern
oil mills (Hartley 1988: 7035).
presses described here provided a relatively efficient process
for the step of pressing out the oily liquid during oil production
and led researchers to seek improvements in the other steps. Several
innovations have resulted from a project begun by the Nigerian
Institute for Oil Palm Research (NIFOR) during the 1950s in cooperation
with the Food and Agriculture Organization of the United Nations
(FAO) and the United Nations Development Program (UNDP).
following unit operations and equipment are involved in palm oil
bunch cookers, which are wood-fired cylindrical tanks. They
are loaded with cut-up fresh fruit bunches (FFB).
bunch stripper operated by hand, which consists of a cylinder
made up of slats and turns on a horizontal axis that tumbles
the cooked bunch sections until the individual fruits separate
from the bunch and fall between the slats.
digester (to break up the softened fruit and release its oil
from its cells), consisting of a horizontal cylinder in which
beater arms rotate, driven by a small diesel motor.
hydraulic press, which was introduced in 1959.
clarification unit consisting of two linked tanks, whereby heating
with water causes the oil layer in the first tank to overflow
at the top into the second tank. There it is dried by the waste
heat from the fire under the first tank.
efficiencies of 87 percent at a free fatty acid (FFA) level of
below 4 percent are routinely attainable by this process. Between
a quarter and a half ton of fresh fruit bunches per hour can be
processed, depending on cooker capacity.
number of variants of this process are in use:
are allowed to ferment so that only loose fruit is loaded into
the cooker. This variant yields oil of higher FFA.
hydraulic presses may be driven by a small diesel engine.
can take place in simple tanks with direct heating.
of bunches may be by steam, whereby whole bunches are loaded
into a tank fitted with a perforated plate about 15 centimeters
(cm) from the base. Water is boiled under the plate, and the
steam penetrates through the bunches.
Ghana, an interesting operating procedure has been developed,
in which the mill owner provides mill facilities to the farmers,
who are then responsible for the bunch stripping and cooking
the fruit. Mill operatives carry out digesting and pressing
procedures, after which the farmers take away the oil from their
own fruit for clarification (G. Blaak, personal communication,
advantages for the farmers are numerous: They need no capital
investment in mill equipment; there are no arguments regarding
purchase price of FFB; if farmers produce high-quality Tenera
fruit, they retain the full benefit; and farmers pay only a processing
charge. Their net profits are higher than those obtained selling
FFB, even if they employ labor to carry out their share of the
small-scale processes just described are suitable for the processing
of FFB from wild oil palm groves or from smallholdings. The main
objective is to produce red palm oil for traditional food use.
processing of the large quantities of fruit produced by plantations
or by large smallholder cooperatives, however, requires a progressively
greater degree of mechanization and mechanical handling as the
quantity increases. Furthermore, since oil produced on a large
scale is usually intended for export or for local refinery processes,
the ultimate objective is a neutral oil of bland flavor and nearly
white color. To attain this quality, the processes (including
the handling of FFB) are designed to minimize the development
of free fatty acids and oil oxidation.
simple factory process of intermediate scale, in which the material
is still handled manually between processing stages, is the Pioneer
mill, which was developed by the United Africa Company around
1939. It is designed to process about three-quarters of a ton
of fruit per hour, which is the equivalent of about 1 ton of fruit
bunches, following the removal of the fruit from the bunch stalks.
The process consists of the following steps:
200 kg of fruit is loaded into a vertical batch autoclave
mounted on a gantry and cooked under steam pressure of 20 pounds
per square inch for 15 minutes.
cooking, the fruit is discharged by gravity into a digester
fitted with a stirrer, which breaks it up and releases the oil
from the cells.
resulting mash is treated in a basket centrifuge, operating
at 1,200 revolutions per minute.
oil flowing from the centrifuge passes through a screen to remove
the fiber, and then to a settling tank.
settling tank contains a layer of hot water, and the oil is
pumped in below water level. The water is boiled for 15 minutes
and then allowed to settle. The oil layer is decanted through
a hot-water layer in a second settling tank.
tank is heated to boiling point for 15 minutes and allowed to
settle. The clean oil is put into drums.
sludge from the two settling tanks is further treated by boiling
and settling, and the residual oil is recovered.
oil mill of essentially the same design, with a capacity of 2
to 3 tons of fruit per hour, was featured in the Wembley Exhibition
of 1924 by Nigerian Products Ltd., Liverpool, and was apparently
demonstrated in operation there (Elsdon 1926: 31622). In
1950 there were 13 Pioneer mills in operation in Nigeria. The
numbers increased to 65 in 1953 and more than 200 in 1962, producing
about 25,000 tons. But, subsequently, their use has declined (Mulder,
personal communication, 1968).
Pioneer mill cannot meet the needs of well-established plantations
generating large volumes of fruit. To keep costs down and output
up, it is vital to have a fully mechanized power-operated mill.
The development of such mills began in Kamerun and in the Congo
before World War I. Mills using centrifuges for oil extraction
were in operation in the Congo in 1916, in Sumatra in 1921, and
in Malaya in 1925 (Hartley 1988: 7035). Centrifuges were
largely replaced by hydraulic presses in the 1930s, although they
were still being operated at Batang Berjuntai, Malaysia, in 1982.
Batch-fed hydraulic presses were, in turn, replaced by continuous
screw presses, which saved labor and handled much larger volumes
of fruit. At this final stage of innovation, the development of
agricultural and processing technology went hand in hand. The
screw press tended to mangle the fruit of the Dura palm, with
its relatively thin layer of oil-bearing mesocarp, but proved
ideally suited to the Tenera variety (Maycock, personal communication,
principal steps involved in the production of palm oil today are
at optimum ripeness.
FFB to an oil mill with minimum bruising.
FFB to sterilizing cages.
FFB by steam under pressure.
cooked FFB to a bunch stripper.
fruit to a digester.
in single-screw or twin-screw press.
oily discharge from the press, containing water and fruit debris,
is passed through screens and settling tanks.
oil phase from the settling tanks is passed to a clarifying
centrifuge. The sludge, or heavy phase, from the settling tanks
is centrifuged and the recovered oil returned to the settling
West Africa, palm oil has a wide range of applications. It is
employed in soups and sauces, for frying, and as an ingredient
in doughs made from the various customary starch foods, such as
cassava, rice, plantains, yams, or beans. It is also a condiment
or flavoring for bland dishes such as fufu (cassava). A
basic dish, "palm soup," employs the whole fruit. The
following dishes from Ghana are illustrative of the wide range
of palm oil use (Wonkyi Appiah, personal communication, 1993).
the case of palm soup, first wash and boil palm fruits. Next,
pound the fruit and mix with water to a paste. Add meat or fish,
vegetables, onions, spices, and salt. Boil for 25 minutes and
simmer for a further 15. Serve the soup with cooked rice, yam,
plantain, fufu, or kpokpoi. (The latter is a corn
dough, steamed and cooked, with okra and palm oil stirred in.)
oil is also used in baked dishes, and one popular dish has different
names according to the local language. When Ofam in Twi,
or Bodongi in Fanti, is prepared, ripe plantains are pounded
and mixed with spices, some wheat or corn flour, beans, and perhaps
eggs. Palm oil is stirred into the mixture and the whole is then
baked in the oven. The dish is served with ground nuts. Apiti
is a similar dish, baked in leaves, without beans or eggs.
characteristic flavor of palm oil prepared by village methods
is an important feature of these dishes. Indeed, it is one of
their most "traditional" features. Several of the other
key ingredients, such as salt, wheat, or (in popular eastern Nigerian
dishes) stockfish, became widely available only in the nineteenth
and early twentieth centuries, when they were imported from Europe
in exchange for palm oil itself (Martin 1988: 289, 50).
fully flavored red palm oil produced by West African village methods
has not proved suitable for food use in the importing countries
of the West, where the consumer requires a bland cooking fat,
near white in color, or a margarine, similar in appearance to
butter. Todays plantation-produced palm oil can be bleached
and neutralized to meet Western requirements, but in the nineteenth
and early twentieth centuries, the high FFA content even of "soft"
West African palm oils made them too difficult and uneconomic
to neutralize (Andersen 1954: 27). Even before loading aboard
ship, they fell far short of the current quality standard of less
than 5 percent FFA, 0.5 percent moisture, and 0.5 percent dirt;
and a slow ocean voyage did little to improve matters, as the
acidity tended to increase en route (Vanneck and Loncin 1951).
the nineteenth century, exported oil from West Africa was placed
in wooden casks usually supplied from Europe in the "knocked
down" state and put together before being filled. Sailing
ships became much larger in size and were gradually displaced
in the second half of the century by steam ships, which were able
to call at a greater number of ports and make more regular voyages
(Lynn 1989). This development probably improved the overall quality
of oil arriving in Europe, but as the oil was still made on a
small scale by different methods and carried in casks, there was
plenty of variation.
quality problem could have been resolved in the late 1920s, when
bulk storage tanks were installed at some African loading ports,
initially in Nigeria and the Belgian Congo. It was then possible
for incoming oil to be washed and cleaned before bulking, with
an improvement in quality (Iwuchukwu 1965; Mulder, personal communication,
1968). However, hardly any Nigerian palm oil was suitable for
the European food industry until the 1940s.
Sumatran and, later, Malayan plantations started to export oil
in the 1920s, their fruit was harvested systematically from the
beginning. It was transported with minimal bruising to the factories
and processed in a standardized way. Bulk shipment was developed
from the outset. The first shore tanks were installed at Belawan
in North Sumatra in the 1920s, and oil from Malaya was taken there
by steamer from 1931 onward. In 1932 the Malayan planters set
up their own Palm Oil Bulking Company with an installation at
Singapore (Shipment of palm oil in bulk 1931; United Plantations
Berhad, unpublished documents; T. Fleming, personal communication,
thus became possible to develop and maintain the quality standards
that are now current worldwide. The planters aimed to produce
oil of 3.5 percent FFA, which would then fall well within the
limit of 5 percent FFA on arrival in Europe or America. Oil arriving
at above 5 percent FFA was sold at a discount, depending on the
excess acidity (Hartley 1988: 687).
food manufacturers could now begin to introduce palm oil on a
commercial basis, drawing on earlier experiments and fitting it
into two long-standing patterns of fat use. In central and northern
Europe, indeed in cool weather regions generally, the traditional
fats are the products of the farm yard butter, beef tallow,
and lard. In southern Europe, with its dry hot climate, olive
oil has been in general use for thousands of years. Thus, consumers
have had available either a plastic product of solid appearance
or a clear liquid oil, and the cooking and eating habits developed
for these traditions led to the invention in 1869 of margarine
and its development as a replacement for butter, when the latter
was in short supply. Margarine was originally made from beef fat,
and the plastic nature of butter was attained by blending in a
liquid fraction separated from beef fat by crystallization. Margarine
proved so popular that European supplies of beef fat did not suffice.
Imports from the New World were important in the nineteenth century,
but various imported vegetable oils gradually took the place of
beef fat margarine blends as refining techniques developed. The
fact that even "soft" palm oil is a solid fat in temperate
climates, with a consistency quite similar to butter, made it
an obvious candidate for such experiments, and the first recorded
trial took place in 1907 (Feron 1969).
refining and bleaching process required to render suitable palm
oil involved a great deal of research and empirical know-how.
Illustrative is some unpublished correspondence (copies held by
K. G. Berger) between Dr. Julius Lewkowitsch, a consultant chemist
in oils and fats, and a Liverpool trading house, the African Association
Limited. Dr. Lewkowitsch had invented a process for rendering
palm oil into an edible product and had entered into an agreement,
dated January 24, 1905, to share the costs of development of the
process with the African Association.
the work proceeded rather slowly, because in September 1907, Lewkowitsch
received a letter from the Vice-Chairman of the African Association,
saying: "I have sent you under separate cover a sample of
refined beef suet. . . . Would it be possible to
have the samples of the palm oil products made up to appear like
this sample? I am afraid I shall never satisfy my Co-Directors
until I can show them a palm oil product they can eat." A
successful prototype was probably produced eventually, because
in 1910 a small manufacturing concern, V. B. Company, was incorporated
and the African Association was paying Lewkowitsch a regular salary
as managing director from 1910 to 1912.
first decade of the twentieth century also saw the introduction
of hydrogenation of oils, a process by which liquid oils could
be turned into plastic or hard fats to a controlled degree. As
a result, vegetable oilbased "shortenings" were
produced to replace lard and beef tallow as ingredients for cakes,
pastries, and biscuits and as frying fats. Once adequately refined,
palm oil was easily introduced in blend formula for these types
of products and had the advantage of not requiring hydrogenation.
By the mid-1930s, the relatively clean and less acidic plantation-produced
palm oil of Malaya and Sumatra was finding a ready market in the
United States, where it was used not only in fine toilet soaps
but also in the making of compound lard. Over 50,000 tonnes per
annum were used in the American compound lard industry between
1935 and 1939 (Lim 1967: 1302).
interruptions of supplies from Asia during the 1940s forced American
manufacturers to find substitutes for palm oil, and the market
was slow to revive afterwards. However, in Britain, wartime shortages
of butter encouraged the use of palm oil in both margarine and
compound lard, and this market continued to grow in the 1950s
(Lim 1967: 131). British manufacturers, through the home Ministry
of Food and the West African Produce Control Board, were able
to corner the market in British West African palm oil (Meredith
1986). The Produce Control Board and, from 1949, its successor,
the Nigerian Oil Palm Produce Marketing Board, played an important
role in bringing the quality of this oil up to the standards set
in Southeast Asia.
grading system was set up as follows:
Grade I under
9 percent FFA
Grade II 9
to 18 percent FFA
Grade III 18
to 27 percent FFA
Grade IV 27
to 36 percent FFA
Grade V over
36 percent FFA
prices were paid for the better grades, and there was an immediate
response from the village producers, which enabled a Special Grade
palm oil to be specified in 1950 with maximum 4.5 percent FFA
at time of purchase. A significant premium was paid for this oil,
with the result that Special Grade oil, which was only 0.2 percent
of production in 1950, jumped to over 50 percent by 1954. In 1955,
the specification was tightened to 3.5 percent FFA, and by 1965
Iwuchukwu (1965) reported that more than 80 percent of material
for export had reached this quality.
development (mainly since the 1950s) of convenience foods and
of snack food manufacture on an industrial scale opened up additional
uses for palm oil, because of its good resistance to oxidative
deterioration and its better ability to withstand the high temperatures
used in frying than most alternative oils (Kheiri 1987; Berger
1992). The market developed especially rapidly after 1970, as
the trees planted during the 1960s in Malaysia matured and as
the Malaysian government and estate sector began to promote their
product more actively in the West. Asian markets had also become
important by 1980, as Western processing techniques were applied
to meet local needs.
II.E.3.1 shows that the world production of palm oil, together
with its share in world supplies of oils and fats, increased dramatically
from 1970 onward. Yet by this time, in many parts of Africa the
industry had declined (Table II.E.3.6). Nigeria, for example,
had no exportable surplus of oil after 1970 and, in fact, became
a net importer of palm olein in the 1980s. Exports from Zaire
became very limited in the 1980s, and the Ivory Coast, with exports
of 60,000 to 100,000 tonnes per annum, was left as the only significant
African supplier. Meanwhile, as shown in Table II.E.3.6, new Asian
producers were emerging, in particular Papua New Guinea and Thailand.
By 1990, exportable surpluses of 10,000 to 30,000 tonnes per annum
were also reaching the world market from Honduras and Costa Rica
(Mielke 1991: 111).
Malaysian production grew, both the planters and the government
realized that it was vital to improve processing methods and to
encourage the growth in demand for palm oil. The estate sector
took the lead during the 1960s, developing higher grades of crude
palm oil to suit European needs. Later, the government joined
in the development of refineries and new products to suit Asian,
as well as Western, tastes.
old standard of 3.5 percent FFA on leaving the factory continued
to apply to the bulk of crude Malaysian palm oil. However, in
the last 30 years it has been recognized that the production of
a stable refined palm oil of good color is also dependent on characteristics
other than FFA content, as shown in Table II.E.3.7. In particular,
the degrees of oxidation and contamination with catalytic traces
of metals are important. But surveys indicate that the peroxide
value (a measure of the state of oxidation) of standard palm oil
arriving at Malaysian ports or refineries fell from 3.9 milligrams
per kilogram to 2.3 milligrams per kilogram between 1974 and 1991
(Jacobsberg 1974; Wong 1981; V. K. Lal, personal communication,
both in the Belgian Congo (Zaire) and in Malaysia, also sought
to develop a premium product with exceptionally low FFA, obtained
through stricter harvesting routines and processing with minimum
delay. "Special Prime Bleach" (SPB) grade was developed
in the Belgian Congo (Loncin and Jacobsberg 1965), having a maximum
of 2 percent FFA and reduced levels of iron and copper contamination,
while in Malaysia two special grades became available, namely
"SQ" and "Lotox." The SQ and Lotox specifications
include limits for oxidation characteristics as well as trace
metals and in practice satisfy the most stringent requirements
of the European market (Johansson and Pehlergard 1977).
separate development, which also improved the quality of palm
oil arriving in Europe, was the introduction in the 1960s of "parcel
tankers." These are specialized ships of up to 30,000 tons.
The cargo space is subdivided into a number of separate tanks,
generally with a capacity of between 100 and 1,000 tons. Tanks
are fitted with separate pumps and pipelines so that different
liquid cargoes can be carried without contamination. With the
very large export trade from Southeast Asia, parcel tankers are
capable of economically carrying palm oil and other oils of different
grades to destinations all over the world. Appropriate shore installations
have been developed since 1960 in the exporting ports of Southeast
Asia and in most receiving ports in Europe, United States, and
Japan, and are being developed in countries that have only recently
become large importers. Like the development of bulk shipment
from Malaya in the 1930s, this innovation was fostered by cooperation
among the planters, who marketed their oil through a common Malayan
Palm Oil Pool from 1953 to 1974 (Allott and Wong 1977).
1974 the volume of Malaysian oil exports and the diversity of
markets had grown to the point at which a free marketing system
was more appropriate. The range of palm oil products exported
was also growing, following the application of the fractionation
process first developed for beef tallow in the 1870s. This technique
separated crude palm oil into olein and stearin. The olein remains
a liquid oil in hot climates and, therefore, readily fitted into
the large Indian demand for cooking oil.
1970 the Malaysian government encouraged and licensed private
enterprises to set up refineries that could both fractionate palm
oil and use it in a more traditional manner to produce shortenings
for Asian markets. In India, for example, there is a large consumer
demand for vanaspati, a shortening developed as a replacement
for butterfat ghee. Similar shortening products are traditional
in Pakistan, Egypt, and other Middle East countries. Often lacking
their own refining facilities, such countries have tended to import
palm oil products from Malaysia in fully processed, ready-to-eat
Malaysian government encouraged this trend by offering tax concessions
for refineries in their early years and by progressive remission
of the export tax on crude palm oil, graded according to the degree
of processing of the end product. This development received a
mixed reaction in Western Europe, which had ample processing capacity
and extensive technical know-how (Berger, personal observation).
However, it proved successful in stimulating the growth of new
Asian markets, as shown in Table II.E.3.8.
private enterprises had an excellent record in developing new
processing techniques, they often felt hampered by their distance
from major markets, which posed difficulties in designing and
introducing new products. In 1979 the Malaysian government set
up a specialized Palm Oil Research Institute (PORIM) as a statutory
body, financed by a levy on palm oil production. A major part
of its mission was the development of application technology for
palm oil and the propagation of the information to end users anywhere
in the world. By studying consumption patterns of oils and fats,
the Institutes staff was able to identify potential new
markets and provide the technical input needed for their development
(PORIM 1981: 15). Their work proved useful to producers
worldwide, especially from the late 1980s on when a debate arose
over palm oils nutritional value.
Properties of Palm Oil
the general nutritional functions of fat are to:
the essential linoleic and linolenic acids.
the fat soluble vitamins A, D, and E.
the palatability of foods.
specific nutritional properties of palm oil may be considered
in relation to its chemical composition. Typical values are given
in Table II.E.3.9.
unsaturated acids present are mainly oleic, with a useful level
of linoleic and a small amount of linolenic acid. In consequence,
palm oil has a high stability to oxidation. Palm oil is readily
absorbed and shows a digestibility of 97 percent or greater, similar
to that of other common edible oils.
in other vegetable oils, the middle 2-position is mainly occupied
by unsaturated fatty acids. This is different from animal fats,
where the 2-position is usually occupied by a saturated fatty
or "virgin," palm oil is one of the richest natural
sources of carotenoids. Regrettably, these are removed during
the industrial refining process so that their nutritional benefits
are lost, except to populations who traditionally use palm oil
in the unrefined state.
tocopherol content (see Table II.E.3.10) is one of the most interesting
features in palm oil because it consists mainly of the tocotrienols,
with an unsaturated side chain. These are not found in the other
common vegetable oils.
work has shown that an average of 50 to 60 percent of the tocopherol
content remains after refining, but the extent of removal depends
on the refining conditions used. The tocopherols are important
natural antioxidants, although their antioxidant activity is somewhat
lower than the synthetic phenolic antioxidants permitted in foods.
They are less volatile and, therefore, more persistent in high-temperature
conditions, such as in deep-fat frying. The tocopherol content
is a major factor in stabilizing palm oil against oxidation. The
nutritional benefit of tocopherols in a number of disease conditions
in which free radicals or oxidation are implicated has become
a very active field of research, although to date little has been
done on tocotrienols as such.
three major component fatty acids of palm oil palmitic,
oleic, and linoleic acids are also the most common fatty
acids found in vegetable oils. Palm oil has been used as a traditional
food in West Africa probably for thousands of years, which provides
some evidence that it has good nutritional properties.
into coronary heart disease in relation to diet led to the general
hypothesis of A. Keys, J. T. Anderson, and F. Grande (1957) that
saturated fatty acids raised blood cholesterol levels, whereas
linoleic acid reduced them. Subsequent refinements of the hypothesis
(Hegstedt et al. 1965) indicated that saturated acids did not
all have the same effect. In particular, D. M. Hegstedt and colleagues
concluded that myristic acid was 3 to 4 times more effective than
palmitic acid in raising blood cholesterol levels.
early work leading to these hypotheses did not use palm oil in
the experimental diets. However, between 1985 and 1987, concern
was expressed in the media, principally in the United States,
that the saturated fatty acid content of palm oil meant that it
would raise blood cholesterol levels and was, therefore, an undesirable
food component. This assertion was not based on any direct experimental
evidence. Instead, a review of the few dietary experiments in
which palm oil had been used (as a control, not as the subject
of investigation) showed that, in general, a small reduction in
blood cholesterol level was experienced (New findings on palm
a study in Nigeria, a principal traditional consumer of palm oil,
was published (Kesteloot et al. 1989). Serum lipid levels were
measured in 307 men and 235 women, whose ages were 15 to 64 (mean
38.8) for men and 15 to 44 (mean 31.4) for women. Mean values
for total serum cholesterol were 156.3 and 170.9, respectively,
and for HDL cholesterol 46.0 and 49.0. Subjects consumed their
normal diet, with 84 percent of the fat intake from palm oil.
These serum lipid levels compared very favorably with black and
white populations in the United States, where total fat intake
is much higher, and where palm oil comprises only 1 to 2 percent
of total fat intake (Park and Yetley 1990).
number of new dietary studies have addressed the nutritional properties
of palm oil, particularly in its effect on blood lipids. T. K.
W. Ng and colleagues (1991), for example, found that when palm
olein formed 75 percent of fat intake in a normal Malaysian diet,
total serum cholesterol was significantly reduced, by 9 percent
from the level at entry, and that the reduction was almost entirely
in the undesirable LDL cholesterol. The study was carried out
on 20 men and 7 women of average age 24.
Marzuki and colleagues (1991) used 110 residential high school
students of both sexes as subjects (ages 16 to 17). Although the
normal menu was provided, palm olein was the sole cooking oil
for 5 weeks. This was followed by a "washout" period
of 6 weeks on regular cooking oil and a second experimental 5
weeks in which only soya bean oil was used. There was no difference
in plasma total LDL or HDL cholesterol between the two trial periods.
Sundram and colleagues (1992) carried out a double blind crossover
study on 38 men, in which 70 percent of the fat in a normal Dutch
diet was replaced by palm oil. There was no effect on total serum
cholesterol, but a significant increase of 11 percent in HDL 2
cholesterol, resulting in a beneficial decrease in the LDL/HDL
2+3 ratio. G. Hornstra and co-workers (1991) also measured plasma
lipoprotein (a), which is strongly associated with an increased
risk of ischemic cardiovascular disease. They found a highly significant
10 percent decrease in this component during the test diet period,
and the decrease was greatest in subjects with an initial high
level of lipoprotein (a), that is, those with an enhanced risk.
Wood and colleagues (1993) examined the effect of six different
fats used as components of items of a normal American diet on
30 middle-aged men. When refined palm oil formed 60 percent of
the dietary fat intake, there was no significant effect on total
cholesterol, but HDL cholesterol was increased compared with the
and colleagues (1992) studied 33 subjects consuming a Malaysian
diet containing 34 percent of calories as fat. When palm olein
was 23 percent of energy (that is, two-thirds of the fat intake),
there was no significant difference in serum total LDL
or HDL cholesterol contents from the levels at entry. The use
of olive oil in place of palm olein gave almost identical results,
although the ratio of Thromboxane B2 to Prostacyclin PGFI alpha
was significantly lower during the palm olein dietary period.
Heber and colleagues (1992) found no increase in the plasma total
cholesterol level of 9 subjects, but a small rise in plasma HDL
cholesterol when one-half of the dietary fat was palm oil. The
diet contained 35 percent energy as fat.
S. Truswell and co-workers (1992) conducted 2 trials (21 and 30
subjects, respectively) in which one-half of the dietary fat was
palm olein. He found that a 10 percent increase in HDL cholesterol
accounted for the 3 percent rise in total cholesterol observed.
conclusion is that palm oil, used as a dietary fat at a high level
10 to 20 times that usual in a Western diet does
not raise serum total cholesterol. However, the level of serum
HDL cholesterol (popularly described as the "good" cholesterol,
because in this form cholesterol is catabolized and removed) was
significantly increased in several of the recent studies.
might also be made of two additional studies, by R. C. Cottrell
(1991) and C. E. Elson (1992). These authors reviewed 139 and
180 scientific publications, respectively, and both concluded
that palm oil was a nutritionally satisfactory component of the
diet. Cottrell wrote that "the decision to use palm oil in
food products should be based on a rational appraisal of its technical
performance value rather than on a misconceived view of the health
implications of its use" (Cottrell 1991: 989S1009S).
the view still persists in some circles that palm oil is an unhealthy
tropical grease, and it is difficult for palm oil producers to
counter this perception because the product had little or no public
image among Western and Asian consumers before the start of the
recent media debate. Processed until it has become an anonymous
ingredient, and used in a wide variety of compound fats and such
other items as biscuits, its original flavor and feel have been
lost to most consumers. But now that the wider nutritional benefits
of palm oils natural carotenoids are becoming more generally
recognized, perhaps it is time to rediscover the fully flavored
red oil and promote its use, not only in Africa and Latin America
but also in Asia and the West.
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