THE OIL BEANS, SEEDS AND NUTS OF THE FOREST
In a separate chapter the Oil Palm and its produce are more fully
considered, so that we give here a detailed account of the other
important Oil Seeds and Nuts. Oil-bearing nuts and seeds are usually
found in great profusion in the Tropics, and West Africa is no exception
to the rule.
Amongst the botanical families in which the plants yield oil-seeds or
nuts are the Palmæ, Leguminosæ, Euphorbiaceæ, Ochnaceæ, Sapotaceæ,
Rhizophoraceæ, Meliaceæ and Guttiferæ. As far as the Protectorates of
Nigeria and Sierra Leone are concerned, the “Oil Bean” (_Pentaclethra
macrophylla_) is one of the most important. According to the data in the
Niger district, oil beans have been bought for some ten years from the
natives. They are also known as Owala beans. The natives prefer a price
of 1s. per case, but the minimum of 6d. and the maximum of 9d. per case
was about the limit for the nuts in pre-war days. Even then only a small
profit was made by the European merchant at the prices then ruling for
the nuts in England. With the much greater, almost universal demand for
all kinds of oil-nuts and seeds, it is probable that higher prices will
be paid for these nuts now that the war is over, provided a reasonable
charge for freight can be arranged. The natives themselves say that the
nuts should be cooked for twelve hours to be good for eating. There are
six or seven beans in each pod.
Now that many roadsides in the Owerri province and other districts have
been planted with Oil-bean trees as a shade tree, there will be a
continual supply of nuts each year. The tree starts bearing in the tenth
year, and almost every year bears a fair crop. An example of one of
these avenues is seen on the Ikpoba Road, just outside Benin City. The
pods are used as a firewood, which makes a hot, rapid fire. In Sierra
Leone they are known as Fai beans. The beans are large and flattened,
covered with a hard brown seed-coat. They may be from one and a half to
two and three-quarter inches in length, and from one to one and three-
quarter inches in breadth, and one-third to nearly half an inch in
thickness. The kernels are white and soft and contain a quantity of oil.
According to the very valuable investigations of the Imperial Institute:
The proportion of hard seed-coat (by weight), 20·7 per cent.
The proportion of kernel in bean (by weight), 79·3 per cent.
The amount of oil contained in the whole, 31·2 per cent.
The amount of oil contained in the kernels, 39 per cent.
When the oil is left to stand it deposits a quantity of solid fat. On
trial, the oil was found to yield rather a soft soap, and was stated to
be worth only about £21 per ton. The cold-pressed oil was of a golden
yellow colour, and the hot-drawn oil a dull yellow and rather thick.
From analysis it was found that the meal was very nutritious, containing
over 39 per cent. of proteids, and if it could be used as a feeding-cake
it would be worth from £5 to £5 10s. per ton (pre-war rates).
The constants of the oil from the Southern Nigerian seeds are:
Iodine value 87·07
Acid value 14·3
Titer test 50·15° C.
The composition of the meal after extraction of the oil is as follows:
Per cent.
Moisture 12·9
Ash 3·5
Proteins 34·8
Fibre 6·8
Sugar (dextrose) 6·2
Carbohydrates (other than sugar) 33·7
The oil on analysis gave the following results:
Specific gravity at 15·5° C. (60° F.) 0·9194
Saponification value 184·2
Free fatty acids, per cent. 0·7
Analysis of pressed cake:
Per cent.
Oil 12·0
Moisture 9·9
Crude proteins 33·2
Carbohydrates 34·8
Fibre 5·7
Ash 4·5
The oil would make a first-class edible oil. The value of the beans is
stated to be about £6 per ton c.i.f. London, August 1909, and subject to
being shipped in lots of fifty to one hundred tons at a time. No regular
plantations have been made with this tree, but it is probable that with
cultivation an earlier and quicker yield of nuts could be obtained, also
with further grafting and seed selecting the thickness of the shell over
the kernel could be considerably reduced, and also the thickness of the
pod, and thus make the product more valuable in proportion to its size.
A small tree will bear half to one bushel of beans, and a large tree
will bear two. On the smaller and younger trees the pods are narrower
and shorter than on the older trees, and the beans are much smaller,
being only about half the size and a third of the bulk of those from
fully-grown trees. The pods, which also contain a certain amount of oil,
are not to be despised as a source of fuel, especially as time goes on
and the population increases.
In this place also should be considered the beans of _Xylia Evansii_.
This is also a Leguminous tree. The natives apparently have no use for
the small, flattened round beans, which are about half to three-quarters
of an inch in diameter and an eighth of an inch thick, and sometimes
less. The beans have not been collected or sold, neither have they been
examined chemically as to their oil or other content.
Another oil-bean-bearing tree of this family is _Berlinia acuminata_,
which has large beans rather more than an inch and a half long, an inch
broad, and a third of an inch thick. Further examination would show
whether the oil content is such as to justify their commercial
exploitation. The Benin name is Ekpagoi and Yoruba Apado.
Closely allied to this one is _Macrolobium palisoti_, the Ogaba of the
Benis, which also yields a flat, almost square-shaped bean, nearly an
inch in length and an inch in width. The exact oil content of this bean
is unknown.
The beans of _Cynometra Afzelii_ and _Cynometra Mannii_ are much larger
and stouter, but also contain a certain amount of oil of unknown value.
The Benin name is Upakeka and Yoruba Eggi or Ekku.
Then we have the small, almost black, button-like beans of _Brachystegia
spicæformis_, which, despite their large quantity, have remained
uncollected and unused. A proper chemical examination would reveal the
oil or other content of the beans. The Benin name is Okwan and the
Yoruba Ako.
Still considering this same family of plants, the Leguminoseæ, there are
the brown beans of _Erythrophlœum Guineense_ and _E. micranthum_. These
are of a brown colour, about half an inch long, one-third of an inch
wide, and an eighth of an inch thick, and of a more or less round shape.
Here, again, further investigation would reveal the oil content of these
beans. The Yoruba name is Oginni or Inyi and Yoruba Erunor Obo.
It is also not known whether the nuts of the various Afzelias, known as
Apa by the Yorubas and Aligna by the Benis, contain a valuable oil or
other commercial product.
It has been stated that the beans and pods of _Pithecolobium altissimum_
have been used as a kind of “Dividivi” for tanning leather, but further
experiment with these would prove or disprove the point.
Finally, there is the Calabar bean or Eseri bean, _Physostigma
venenosum_. It is known to the Efiks as Eseri. The deep furrow on the
upper side of the bean is most typical of it, and differentiates it thus
from the various Mucuna species. It contains two alkaloids, Calabarine
and Eserine. These beans are comparatively well known. Besides being
used locally as a medicine and for witchcraft, they are collected and
sold for export. The bean used in games, _Mucuna urens_, has yet to be
examined as to its value.
Amongst the other important families containing nut-bearing trees are
the Rhizophoraceæ. The Inoy nut, _Poga oleosa_, is obtained from a
common tree in the Owerri and Calabar provinces of Nigeria. The local
people of the Oban and Calabar districts are very fond of the nut, and
leave the tree standing when making their farms. The nuts sell in the
Calabar market at the rate of 250 for 3d. They were examined in England
and favourably reported on by the Imperial Institute in June 1905. The
hard shell is against their general use, as it is so particularly tough
and hard to crack. The shell on the nut itself is about one-fifteenth of
an inch thick. The kernel is soft, white, and very oily. It has a better
flavour than even the Brazil nut, and is pale-yellow in colour. The
kernels were valued in May 1906 at from £9 to £10 in England. They
contain about 60·8 per cent. of oil, which showed the following
constants according to the investigations of the Imperial Institute:
Specific gravity of 15° C. 0·896
Saponification value 184·49
Iodine value 89·75
Hehner value 93·00
Reichert-Meissl value 1·45
Acid value 39·7
Titer test 22° C.
After extraction of the oil the meal gave the following result:
Expressed on Dry Material.
Per cent.
Proteins 41·51
Sugars, reducing 1·32
„ non-reducing (sucrose) 2·50
Other carbohydrates 36·92
Crude fibre 9·00
Ash 8·75
“Inoy” kernels would yield a nutritious cake for feeding cattle.
Thus far no use has been found for the round small, pear-shaped, nut-
like fruits of the Red Mangrove, _Rhizophora racemosa_. Considering the
large quantity found floating about in the creeks and rivers, further
investigation seems warranted.
In the Euphorbiaceæ family the Nsa-sana (Efik) or Okkwen nuts of the
Benis have been found to contain 45·2 per cent. of oil by the Imperial
Institute.[17] This nut is obtained from _Ricinodendron Africana_ and
_R. Rautenii_, and is known to the Yorubas as Erimado. In each fruit
there are two, three, or even four nuts. The flesh of the fruit soon
dries or rots away, leaving the uncracked nuts among the debris. The
shell of these is hard and thick, and the inside a bright white colour.
In some experiments carried out on a comparatively large scale at the
end of 1907 and at the beginning of 1908, in Benin, it was found that
more than half the kernels were broken in the cracking of the nut.
However, in the Cameroons, where the nuts are used for alimentary
purposes, they are boiled for a short time, and then it is possible to
crack them quite easily without damaging the kernel inside. Further
experiments at Benin showed that six boxes (gin cases) of green fruit
yield one box of nuts containing actually 7,528, which weigh 35 lb. 4
oz. One box of fruit contains 418 seeds and yields 720 nuts. An average
of 7,419 seeds is contained in each box, 155 nuts weighing 1 lb. Each
fruit contains on the average two and one-ninth seeds. On the average
9d. per box was paid for fruit, and 1s. per box for uncracked nuts.
Twenty boys cleaned and got ready 2½ boxes of uncracked nuts per day at
the cost of 5s. Paying at the rate of 1s. a case for the uncracked nuts,
the cost would be £17 per ton. However, with regular quantities being
brought in, no doubt this cost could be reduced. In a similar way, if
the nuts were boiled in quantity and immediately cracked, the kernels
would be got out at a cheaper rate. The native working for himself, as
with the palm nuts, would turn out greater quantities in a shorter time.
The yield of the oil pressed from the kernels was 47 per cent., or 14
per cent. on the whole nut. It is light yellow in colour and has a
pleasant taste, very much like that of the ground nut. The chemical
examination showed a resemblance to Tsung oil (Chinese wood oil). It
possesses the same property of drying on exposure to air under ordinary
atmospheric pressure. The oil could be used for similar purposes, or for
the making of soft soap, and would be worth from about £18 to £20 per
ton for this purpose, and it appears that the oil would have a ready
sale in England, and have a value, equal to linseed oil, of about £21
per ton. According to the investigations at the Imperial Institute, the
analysis of Nsa-sana kernels and Tsung oil showed:
---------------------+-------------------+--------------------------
| Oil from Nsa-sana | Commercial Tsung Oil.
| Kernels. |
---------------------+-------------------+--------------------------
Specific gravity |0·9320 (at 20° C.) |0·933-0·942 (at 15·5° C.)
| |
Saponification value | 191·6 | 190-197
| |
Iodine value | 147·7 | 149-165
| |
Hehner value | 95·2 | 96·3
| |
Titer test | 35·7° C. | 37·1-37·2° C.
---------------------+-------------------+--------------------------
Despite the large quantities of nuts available, especially in the
Abeokuta, Benin and Calabar provinces, the difficulty of cracking the
nuts satisfactorily and buying them cheap enough has so far precluded an
export trade from being built up. Owing to the low percentage of oil in
the whole nut it is evident that it would not pay to ship the uncracked
nuts. So far no plantations have been made with this tree, but it comes
up very readily and plentifully in old abandoned farms of the mixed
forest zone. In open localities, with plenty of light, the tree begins
to bear between the seventh and tenth year, and almost each year there
is a large crop of fruit. From larger trees the yield appears to be over
one bushel of nuts per tree per annum.
The curious nut-like fruits of Ubellu, Benin, supposed to be a species
of Microdesmis, have not been examined as to their oil or other content.
Soon after falling to the ground they break up into a white putty-like
substance, which has a very peculiar, almost sulphurous, smell, and
sometimes rather phosphoric. The nuts are spherical and rather more than
half an inch in diameter. The tree is found chiefly in Benin, also in
the Abeokuta and Calabar provinces.
Among the Euphorbiaceæ is the creeper, _Manniphyton sp._, known as Okwe
to the Benis. The spherically shaped fruit with four raised ribs on its
surface is cut open and contains one large round nut. It is about one
inch in diameter. This is boiled for a few hours and is then edible,
after the thin dark-brown husk has been removed. It can be peeled off
with the fingers. The nut has a pleasant mealy taste and is very
satisfying. Further examination would show whether it contains a
valuable oil, and in what quantity. So far it has not been cultivated.
Of the Cucurbitaceæ, the seeds of _Citrullus vulgaris_, known as Ikpan
by the Efiks or Egusi bara by the Yorubas, have been examined at the
Imperial Institute[18] and found to contain from 40 to 41 per cent. of a
pale-yellow oil. It is a common plant in the more open farms of the
forest and does not demand a very high rainfall—45 inches. The natives
use the kernels, after they have removed the hard skin, for making soup.
It makes an excellent dish with rather a sweet taste. According to the
investigations of the Imperial Institute[19] an analysis of the oil gave
the following results:
Specific gravity at 15° C. 0·9184
Acid value 5·5
Saponification value 194·0
Iodine value 106·0
Hehner value 95·5
Titer test 36·0° C.
The oil could be used for soap-making, and was valued at £29 per ton.
In the family Moringeæ there is _Moringa pterygosperma_, the Ben oil-
seed tree. It is a common tree of the upper part of the Oyo, Benin and
Ogoja provinces of Nigeria. It is also found in Borgu and other of the
Northern Provinces. On examination by the Imperial Institute the kernels
were found to contain 38 per cent. of oil, pale-yellow in colour and of
a pleasant taste. The kernel is difficult to extract. At the Imperial
Institute[19] the analysis showed:
--------------+---------------------+---------------------+-----------
| No. 1 from | No. 2 from |No. 3 from
| Extracted Oil. | Decorticated Seed. |Undecorti-
| | |cated Seed.
+----------+----------+----------+----------+-----------
| Liquid. | Solid. | Cold | Hot | Hot
| | | Pressed. | Pressed. | Pressed.
--------------+----------+----------+----------+----------+-----------
Specific | 0·914 | — | 0·902 | 0·898 | 0·913
gravity at | | | | |
15/15° C. | | | | |
| | | | |
Acid value | 15·3 | — | 49·7 | 100·5 | 2·3
| | | | |
Saponification| 189·2 | 194·4 | 179·2 | 178·7 | 186·0
value | | | | |
| | | | |
Iodine value | 70·7 | 68·3 | 100·3 | 88·0 | 67·7
| | | | |
Unsaponifiable| — | — | 1·67 | 2·69 | —
matter | | | | |
--------------+----------+----------+----------+----------+-----------
COMPOSITION OF CAKE FROM BEN SEEDS.
--------------------------------+-------------+---------------
| No. 2, | No. 3
|Decorticated.|Undecorticated.
--------------------------------+-------------+---------------
| Per cent. | Per cent.
| |
Moisture | 5·96 | 7·5
| |
Albuminoids | 24·12 } |
| } | 30·8
Other nitrogenous substances | 34·81 } |
| |
Fat | 11·27 | 14·5
| |
Fibre | 4·32 | 21·9
| |
Ash | 5·66 | 4·5
| |
Other non-nitrogenous substances| 13·86 | 20·9
--------------------------------+-------------+---------------
From the Simarubeæ there is _Balanites Ægyptica_, Betu oil-tree of the
Northern Provinces of Nigeria. Although it yields 58·7 per cent. of oil,
the exploitation of it is almost impossible, owing to the difficulties
in removing the husk, the external sugary pulp, and then the thick
fibrous shell under the pulp. At the Imperial Institute,[20] Betu oil on
analysis showed:
Specific gravity 0·919
Acid value 5·0
Saponification value 196·7
Iodine value 92·5
Hehner value 92·5
Reichert-Meissl value —
Unsaponifiable matter 0·6
Titer test 34·6° C. (approx.)
The oil is a mixture; the results of analysis are as follows:
Per cent.
Olein 33
Linolein 33
Stearin and palmitin 34
The family of Simarubeæ also contains the trees _Irvingia Barteri_ and
_I. Smithii_. These yield the Dika nut, or, as it is sometimes called,
Gaboon chocolate. The sun-dried kernels keep in a perfectly good
condition for some time. According to the investigation of the Imperial
Institute[20] the kernel contains about 43·5 of “Dika fat.” It would be
useful either for soap or for candle making, and be worth from £25 to
£27 per ton, and the Dika kernels are valued at from £10 to £12 per ton.
Locally, however, they are often worth as much as this, but no doubt
increased production would mean a reduction in price. So far the tree
has only been planted in isolated instances, and otherwise is a forest
tree which has been protected by the native for the value of its fruit.
The decortication usually takes place near the tree, or in an open place
where the nuts are split in half with a sharp matchet, which releases
the kernel in the centre, and though often cut in half by this method,
it apparently does not mean a large loss of oil to the kernel. According
to the analysis of the Imperial Institute[20] the kernel showed:
------------------------------------+---------+---------+--------
| Sample | Sample | Sample
| No. 1. | No. 2. | No. 3.
------------------------------------+---------+---------+--------
Yield of fat (on kernels) per cent. | 54·3 | 60·1 | 66·3
| | |
Specific gravity at 100/15° C. | — | 0·863 | —
| | |
Acid value | 6·6 | 12·6 | 1·8
| | |
Saponification value |244·5 | 250·0 |243·8
| | |
Iodine value | 5·2 | 3·3 | 4·2
| | |
Unsaponifiable matter | 0·7 | — | —
| | |
Titer test | 34·8° C.| — | —
| | |
Melting-point of fat | — | — | 39·2°C.
------------------------------------+---------+---------+--------
Apparently an oil seed, probably Philiodiscus, a member of the
Sapindaceæ family, has been examined at the Imperial Institute and has
been found to contain a non-drying oil, which was free from taste and
smell. It should, therefore, be of value for eating or for making a
white soap.
Sapotaceæ, _Butyrospermum Parkii_.—In recent years larger quantities of
Shea nuts, which are the product of this tree, have been exported from
West Africa, especially Nigeria, as also Shea butter, which is
manufactured locally from the nuts. In the varieties Tengba and Bomo the
quantity varied from “54·5 per cent. to 48 per cent.,” and these were
obtained from the Southern Provinces of Nigeria. In the two varieties
exported from the Northern Provinces, those known as Eko showed a length
of nut varying from 1·5 to 2·5 inches, and the Giddouchi variety 1·4
inches long. Owing to the wide prevalence of this tree much larger
quantities could be exported, but many of the forests containing it are
situated far away from means of transport, and no very suitable method
has yet been found of manufacturing the butter on a big scale locally.
At present it is made by certain women who know the process, which takes
nearly three days to complete. According to the Imperial Institute the
results of the analysis of Shea butter are:[21]
---------------------------------+---------+----------+-----------
| From | Fat from | Fat from
| Lagos. |Untreated |Kiln-dried
| | Kernels. | Kernels.
---------------------------------+---------+----------+-----------
Specific gravity at 100/15·5° C. | 0·862 | — | —
| | |
Acid value | 18·0 | 33·9 | 26·2
| | |
Saponification value |179·0 | 181·2 | 180·2
| | |
Iodine value | 58·7 | 59·4 | 55·8
| | |
Hehner value | 96·5 | — | —
| | |
Unsaponifiable value | 1·7 | — | —
| | |
Titer test | 52·0° C.| — | —
---------------------------------+---------+----------+-----------
The fat obtained from the Northern Provinces and the Gold Coast shows
very similar contents.
_Mimusops, sp. Djave?_.—The nuts of this species closely resemble those
of the Shea Butter Tree. The nuts are a light-brown colour, about two
inches long, and one to one and a half inches in diameter, with roundly
pointed ends. Rather more than half the surface of the nut is smooth and
shiny, and the other half is rough and dull, and the whole of it is very
hard. When dry it is, however, comparatively easily separated from the
kernel. The fresh kernels are cream-coloured. According to the Imperial
Institute[21] the yield of fat extracted by solvents is 60·2 per cent.,
or 37·7 per cent. from the whole nut. The fat is solid at ordinary
temperatures. In 1913 some of these nuts were shipped from the Cross
River and were valued in Liverpool as Shea nuts, only at a rather lesser
rate. According to the Imperial Institute the analysis showed:
Specific gravity at 100/15·5° C. 0·860
Acid value 25·3
Saponification value 187·6
Iodine value 56·2
Hehner value 95·4
Reichert-Meissl value Nil
Unsaponifiable matter 2·6 approx.
Titer test 47·8° C.
_Dumoria Heckeli?_ (Baco or Abaku).—Although the Gold Coast name is
given, these nuts are also found in the Oban forest. The nuts are large,
considerably longer than those of Mimusops, but rather thinner. They are
of a pale-brown colour, with a thick, hard, woody shell, most of which
is smooth and shiny, only one small part of the surface being rough and
forming almost a nodule. According to the Imperial Institute[22]
analysis of the Gold Coast samples, the whole nuts contain 21 per cent.
of fat or 60·5 per cent. in the kernels alone. The fat is solid and of a
creamy white colour. The soap-makers reported that it was about equal to
middling quality palm oil. It is also stated that dried kernels in good
condition would be worth £13 per ton. According to the Imperial
Institute[22] analysis the fat showed:
Specific gravity at 100/15·5° C. 0·855
Acid value 34·7
Saponification value 188·4
Iodine value 51·3
Titer test 51·2° C.
Unsaponifiable matter 1·3
The small nuts of _Mimusops multinervis_ and _M. lacera_ have not been
examined as to their oil or other content. The hard nuts of _M. lacera_
appear to contain a fair proportion of oil.
In this family, too, are the nuts of _Chrysophyllum Africanum_ and other
species, for which a use has yet not been found. Finally, there are the
numerous and fine seeds of _Omphalocarpum elatum_, known as Ikassa by
the Benis, which are probably also oil-bearing.
The next important family is the Olacaceæ, _Heisteria parvifolia_, known
as Ikereoha by the Benis. It yields an edible nut which is white on the
exterior and has a black-coloured shell over the actual nut inside. It
has not yet been exported or valued. The Benin and other natives are
very fond of eating it.
Then there is the nut of Ivialegbi (Benin), which is edible and has a
pleasant taste. It is rather smaller than the Gaboon nut, and its
surface is slightly striated from the sharp point of the nut to the
base.
In this family is found, too, _Coula edulis_, or the Gaboon nut. This is
chiefly found in the Cameroons, but owing to similarity in the
vegetation it is very probably growing in the Oban forest of the Anom
range. The shell of the nut is very rough, and the outside is smoother
than the inside. The shell can be cracked comparatively easily with a
somewhat powerful blow with a hammer or axe-handle.
From the Anonaceæ:
_Monodora tenuifolia_, African Nutmeg.
_M. myristica_, var. _grandis_, Calabar Nutmeg.
_M. brevipes_, Yellow-flowering Nutmeg.
None of these nutmegs have yet been placed on the European market.
Although they are all much smaller in size than the nutmeg of commerce,
a proper examination would reveal any value they might possess.
Although the Myristicaceæ, _Pycnanthus Kombo_, yield fat-bearing nuts,
they have not been exported to the English market. The nut is the size
of a small oval plum. The outer husk is hard and thick, but is
comparatively easily broken. The inner nut is covered with a red aril
spread out over it, similar to the mace over the common nutmeg
(_Myristica fragrans_). The kernel is white inside, with dark rays
penetrating it from the outside. The tree is very prevalent, and yields
a large number of nuts. According to the investigation of the Imperial
Institute[23] “the yield of solid fat was 54 per cent. It has an orange
colour and a bitter taste.” The fat was stated to be suitable for soap
and candle making and the meal as a manure. In Sierra Leone the nuts
were known as Kpoye, and are identical with those known as “Kafu.”
According to the chemical analysis made at the Imperial Institute the
following results were obtained:
Specific gravity at 100/15° C. 0·886
Melting-point 48·5° C.
Saponification value 235 to 245
Acid value 21·0
Hehner value 90·8
Iodine value 48·9
Titer test 45·8° C.
ANALYSIS OF FAT FROM SIERRA LEONE KOMBO SEEDS.
---------------------+--------+----------------
| | Fat Extracted
| Fat as | from Kernels
| Sent. | at Imperial
| | Institute.
---------------------+--------+----------------
Specific gravity | 0·887 | 0·880
| |
Acid value | 33·0 | 31·4
| |
Saponification value |231 | 236
| |
Iodine value | 67·6 | 59·0
---------------------+--------+----------------
Of the Meliaceæ there is _Carapa Guineensis_ (_C. procera_, D.C.), which
yields the Carapa oil. The nuts are roughly tetrahedral in shape, having
a rough reddish-brown shell enclosing one large kernel covered with a
pale-brown papery skin. Good kernels yield about 57 per cent. of oil by
extraction with solvents and 46·7 per cent. by pressure (27 per cent. on
cold and 22 per cent. on heating); it is of a pale-yellow colour and has
a bitter taste. The commercial value of the oil was stated in 1907 to be
£20 10s. per ton according to the valuations made by the Imperial
Institute,[24] and from the same authority we find the Carapa cake is of
a very low manurial value, and is only stated to be worth about £2 per
ton. Some dark-coloured kernels were bought in 1909 at £11 5s. per ton,
and light kernels at £11 10s. per ton. According to the Imperial
Institute the results were as follows:
---------------------------+-----------------+----------------
|Cold Pressed Oil.|Hot Pressed Oil.
---------------------------+-----------------+----------------
Specific gravity at 40° C. | 0·9179 | 0·9174
| |
„ „ 15° C. | 0·9272 | 0·9327
| |
Saponification value | 197·1 | 196·4
| |
Iodine value | 75·6 | 71·2
| |
Reichert-Meissl value | 3·5 | 3·1
| |
Unsaponifiable matter | 1·5 | 2·0
| |
Titer test | 35·4° C. | 36·1° C.
---------------------------+-----------------+----------------
CARAPA CAKE.
Per cent.
Moisture 9·8
Ash 5·9
Nitrogen 2·9
The ash contained:
Per cent.
(calculated on Cake).
Potash, K₂O 1·91
Lime, CaO 0·18
Phosphoric anhydride, P₂O₅ 0·51
Apocynaceæ.—Although the seeds of _Funtumia elastica_ yield oil, it was
not favourably reported on. Perhaps now, with the greater value of all
the oil seeds, some use could be made of it.
Ebenaceæ, _Diospyros Barteri_.—This yields the Ebony nut, which is
small, but edible. The Benin natives are very fond of it. It has not
been exported.
_Diospyros crassiflora_ or _Diospyros dendo_ have a fruit about the size
of a large green plum, which contains four long, thin, almond-like nuts,
which have rather a bitter taste. Although evidently oil-bearing, they
have not been properly examined or tested as to the exact content of oil
or other products.
Rosaceæ.—Although the _Chrysobalanus sp._, or Niko nut, is comparatively
well known, it is by no means fully utilized. Then there is _Parinarium
Gabunense_, yielding the Mahogany nut, of uncertain value.
Anacardiaceæ.—The _Anacardium occidentale_, yielding the Cashew nut, is
so far only utilized near Lagos, where it is growing as a garden escape.
No proper plantations have yet been made of this tree.
Amongst the Palmæ, besides the Oil Palm, we have the Bottle Toddy or Fan
Palm, _Borassus flabellifer_, yielding three or four nuts in each fruit.
These are oil containing, but of unknown value. Considering the large
areas in all the West African Colonies where the Fan Palm is found, some
use should be made of the large number of nuts produced.
Then we have Hyphæne, the Doum Palm, which yields a nut used for making
buttons. Here, again, the large quantities which are found in Africa
ensure a steady amount of produce being placed on the market, provided a
remunerative price is always paid for the nuts. Finally there is _Phœnix
dactylifera_, the Date Palm. Although this is more of a fruit than a
nut, it is included here, as it is found in the forest groves of the
North. Considering the value of its produce and the constant demand
there is for it, a wide extension of its area of cultivation is to be
recommended.
Ochnaceæ, _Lophira alata_.—This is the dwarf Red Ironwood tree, which
yields the “Niam” fat or “Meni” oil. The fruit is roughly conical,
consisting of a reddish-brown fibrous shell, enclosing one kernel. The
kernel is conical in shape, and about five-eighths of an inch in width.
The inside is a pale-yellow colour. The fruit has two uneven-sized
wings, the larger being over an inch in length and nearly half an inch
in width. According to the Imperial Institute[25] the fat is semi-solid
and of a yellowish colour. The kernel contains 31·1 to 43 per cent. of
fat. The fat is suitable for soap-making.
According to the analysis of the Imperial Institute the results were as
follows: For soap-making it is considered to be of the same value as
palm oil, i.e. in November 1911, at Liverpool, £30 to £31 per ton. The
cake obtained from it closely resembled Shea-nut cake and was of a
similar value, i.e. about £3 per ton in Liverpool. The decorticated
kernels, which contained about 40 per cent. of oil, were valued at about
£10 per ton c.i.f. at Liverpool in October 1911. These kernels should
find a ready market in Europe for soap-making, and the cake to be used
as a manure. As the tree is one of the commonest in the dry-zone
forests, ample supplies of the nuts should be always forthcoming,
providing an adequate price to pay for the cost of production is paid
for them.
TABLE I.
_Yield of Fat._
----------------------+--------+--------+----------+---------+--------
| A. | B. | C. | D. | E.
----------------------+--------+--------+----------+---------+--------
Product received | Fruits |Kernels | Fruits | Kernels |Kernels
| | | | |
Condition of kernels | Mostly | Good | Many | Good | fairly
| sound | | partly | | good
| | |decomposed| |
| | | | |
Yield of fat (per | 31·19 | 43·0 | 39·6 | 41·16 | 41·76
cent. calculated on | | | | |
weight of kernels | | | | |
used) | | | | |
----------------------+--------+--------+----------+---------+--------
TABLE II.
_Constants of Fat._
----------------------+--------+--------+----------+---------+--------
| A. | B. | C. | D. | E.
----------------------+--------+--------+----------+---------+--------
Specific gravity | 0·9105| 0·9044| 0·9044 | 0·9019 | 0·9016
| | | | |
Acid value | 18·54 | 25·9 | 33·2 | 47·5 | 48·0
| | | | |
Saponification value |195·6 |181·5 | 194·6 |180·7 |183·3
| | | | |
Iodine value | 68·4 | 69·8 | 70·3 | 72·1 | 72·5
| | | | |
Reichert-Meissl value | — | 0·9 | 0·9 | 0·8 | 0·8
| | | | |
Unsaponifiable matter | 1·49 | 0·5 | — | — | 0·86
| | | | |
Titer test | — | 49·0°C.| 47·0° C.| 47·5° C.| 48·5°
| | | | | C.
----------------------+--------+--------+----------+---------+--------
[Illustration: FIG. 102.—=Oil Palm (Elæis Guineensis), eight years old,
in bearing, showing nine out of the twenty-one bunches of fruit on the
tree.=]
[Illustration: FIG. 103.—=Seven-year-old Oil Palm in bearing, rather
over-pruned, showing male inflorescence just below boy’s finger and
bunch of fruit in the middle of the picture.=]
To face p. 460.
Closely allied to the above is _Lophira procera_, the Red Ironwood Tree,
which yields the Kaku or Ebba kernels. The fruit is usually more sharply
conical in shape than that from _L. alata_. The fruits are small, owing
to the fact that these large forest trees grow closely amongst others,
and the fruits are not so fully developed or filled out as those of _L.
alata_. _L. alata_ usually grows in the open freely, or at most only
just touching a neighbouring tree, and thus the fruit has ample light
for its development. According to the investigations of the Imperial
Institute, the nuts were found to yield 55·2 per cent. of fat, which was
solid and cream-coloured. Owing to the fact that this is a larger yield
than that obtained from the nuts of _L. alata_, the decorticated kernels
were valued at £12 per ton c.i.f. Liverpool. This tree is one of the
most prevalent in the evergreen forests of Nigeria, the Gold Coast, and
Sierra Leone, so that very considerable amounts of the seeds could be
obtained, provided a remunerative price is paid to cover the cost of
production. According to the analysis made at the Imperial Institute[26]
the kernels contain:
Specific gravity at 100/15·5° C. 0·859
Acid value 11·6
Saponification value 190
Iodine value 60
Unsaponifiable value 0·8
Guttiferæ, _Pentadesma Butyracea_.—The Tallow Tree. From this a large
number of fat-yielding kernels are obtained from each fruit. The nuts
are irregular tetrahedral shape. The shell is not very thick and easily
broken when the nuts are dry. When fresh the kernel is lightish-yellow
in colour, and the nut is brown. According to the investigations of the
Imperial Institute the fat obtained is of a pale-yellow colour, and has
a pleasant smell and taste. In smell, in fact, it is very much like Shea
butter.
On analysis it showed:
Specific gravity at 100/15·5° C. 0·859
Acid value 3·6
Saponification value 190·1
Iodine value 41·8
Titer test 50·7° C.
Hehner value 95·0
Unsaponifiable matter 1·7
Reichert-Meissl value Nil
The samples from the Southern Provinces of Nigeria showed rather a lower
saponification and iodine value.
From its appearance and chemical constants it seems possible that this
fat might be used in the manufacture of edible fats. The kernels were
valued, when in good and dry condition, at from £8 to £10 per ton in the
United Kingdom.
_Allanblackia floribunda_.—The numerous nuts or kernels from the large
fruits of this tree have not yet been used for any commercial purpose.
They appear to contain an oil. In this family, too, there is
_Ochrocarpus Africanus_, which has the large edible fruit known as the
African Mammee Apple. This also yields large nuts of an uncertain value,
which are apparently oil or fat bearing.
_Garcinia conrauna_.—The nuts of this, the false or bitter Cola, besides
yielding an edible fruit, are used locally, but further investigations
would show whether they would obtain a regular market as an export
product.
Polygalaceæ, “Cheyi” seed, _Polygala butyracea_, Heck.—This is a common
herbaceous plant of West Africa. The seeds yield a valuable edible fat.
They are about a fifth of an inch long and a tenth of an inch broad. The
seeds are of a brownish-black outside and a greenish-yellow inside.
According to the investigations of the Imperial Institute “the seeds
yielded 39·7 per cent. of a soft yellowish fat. The taste of it was
pleasant, and there was no odour.” According to the Imperial Institute
analysis the “Cheyi” fat showed:
------------------------+---------------+------------------
|Present Sample.|Results previously
| | Recorded.
------------------------+---------------+------------------
Melting-point | 36° C. | —
| |
Specific gravity at | 0·866 | —
100/15·5° C. | |
| |
Acid value | 1·24 | 11·4
| |
Saponification value | 251·0 | 253·0
| |
Iodine value | 52·5 | 49·4
| |
Titer test | 37·85° C. | —
| |
Hehner value | 85·6 | —
| |
Reichert-Meissl value | 45·6 | 45·5
------------------------+---------------+------------------
“The edible fat manufacturers stated that ‘Cheyi’ fat was suitable for
their purpose if it could be proved that it did not contain a poison,
and valued the seeds at £13 to £14 per ton. The oil-seed crushers valued
the seeds at £12 per ton in the United Kingdom.”
N.O. Bixaceæ, according to Thonner, Flacourtiaceæ, _Oncoba echinata_,
Oliver.—This tree bears a large number of seeds, which are known as
“Gorli” seeds. The seeds are long and irregularly shaped, and vary from
a quarter to three-eighths of an inch long, and from one-eighth to
three-sixteenths of an inch broad. The stiff husk is brown in colour.
The seeds without husks are white, waxy and soft. According to the
Imperial Institute investigations the seeds contain 46·6 of fat, which
is hard, white and crystalline. Although the soap made from it was
satisfactory, it did not lose the very peculiar odour which the fat has.
The cake and fat cannot be used as a food because of the large amount of
chaulmoogric acid contained in it, an acid which causes vomiting. The
fat might possibly be of value in candle-making. According to the
Imperial Institute analysis the seeds showed:
ANALYSIS OF “GORLI” SEEDS.
-------------------------------+---------+-----------
|Sample I.|Sample II.
-------------------------------+---------+-----------
|Per cent.|Per cent.
| |
Moisture | 5·8 | 5·8
| |
Fat | 46·6 | 46·6
| |
Crude proteins | 17·5 | 18·1
| |
Consisting of— | |
| |
True proteins | 11·3 | 10·2
| |
Other nitrogenous substances | 6·2 | 7·9
| |
Soluble carbohydrates | Nil | Nil
| |
Starch, etc. | 11·8 | 12·1
| |
Crude fibre | 15·6 | 14·7
| |
Ash | 2·7 | 2·7
-------------------------------+---------+-----------
ANALYSIS OF “GORLI” FAT.
-------------------------------+---------+-----------
| No. I. | No. II.
-------------------------------+---------+-----------
Specific gravity at 15·5° C. | 0·898 | 0·896
| |
Acid value | 4·5 | 22·4
| |
Saponification value |192·4 |193·9
| |
Iodine value | 99·7 | 96·8
| |
Titer test | 57·8° C.| 57·8° C.
| |
Hehner value | 96·5 | 96·5
| |
Reichert-Meissl value | Nil | Nil
| |
Unsaponifiable matter | 1·6 | 1·3
-------------------------------+---------+-----------
The nut of Ogbogo, a Benin tree, is as yet unvalued, though it appears
to be an oil-yielding fruit. There is, too, the long almond-shaped nut
of Oktobun. Although it has a somewhat hard shell, the nut is very large
in proportion, and the kernel seems to be rich in oil. So far no use has
been made of it.