This section is from the book "The Planting, Cultivation And Expression Of Coconuts, Kernels, Cacao And Edible Vegetable Oils And Seeds Of Commerce", by H. Osman Newland. Also available from Amazon: The Planting, Cultivation And Expression Of Coconuts, Kernels, Cacao And Edible Vegetable Oils And Seeds Of Commerce.
One ploughing, ......
One cultivation, ......
One harrowing, ......
Three hand hoeings at 7 1/2 d., .
Harvesting and shelling, ....
The total crop from 6 1/2 acres was 7,318 lbs. of un-shelled nuts, which on shelling gave 4,024 lbs. of sound shelled nuts, or a yield of 619 lbs. of exportable kernels per acre, and at £13 10s. per ton represents a value per acre of £3 14s. 6d.
Experiments in the East Africa Protectorate with two varieties of ground-nuts, Chinese and Shirati, gave yields of 2,700 lbs. and 2,600 lbs. of nuts (in shell) per acre respectively. In the latter case the crop was only sown as a catch crop, and was planted too far apart for profitable cultivation.
The ground-nut, being less sensitive to climatic variations than cotton and much freer from disease, is worthy of the attention of the larger land companies, who could, if interested, encourage their tenants by distributing selected seed and guaranteeing to purchase the crop at one halfpenny per pound after deducting the weight of the seed issued.
* Average price on home market 1914. The price during 1917-18 rose to £70 to £90 a ton.
The nut contains 50 per cent, of fat, 24.5 per cent, of protein, and 11.7 per cent, of carbohydrates, these being the principal nutrient components of vegetable foods. It makes an excellent substitute for peas and beans, possessing several preponderant advantages.
In Nigeria a nutritious and appetising soup is made from the nut. In the United States, where the pea-nut is extensively used, its value is already being recognised. It is said to fatten more rapidly than any other diet, and if eaten regularly in moderation, to be capable of sustaining life indefinitely. An excellent bread and biscuit may be made from the nut, in the making of the latter no lard being required. It may also be used as a beverage, either alone, when it resembles chocolate in flavour, or mixed with pure coffee, when it is better than many of the coffee mixtures now on the market. The oil of the nut is highly esteemed, being regarded as an alternative to sweet or olive oil.
Small quantities of selected grown nuts have been used in England in confectionery as a substitute for almonds. In India they are extensively eaten roasted, and are now made into sweetmeats, being mixed with palmyra, palm, or sugar-cane jaggery.
By far the greater part of the worlds production of ground-nuts is, however, used for the expression of oil, and for many years Marseilles has been the great centre for the ground-nut trade for oil.
Oil is prepared in West Africa by means of crude native wedge presses, or pestle and mortar mills ; such oil is, however, only employed for local use. An advantage of local extraction is that oil can be prepared from nuts in a fresh condition, freight charges are lessened, and the residual cake becomes available for local use.
Coconuts, Kernels, etc.- Capt. H. O. Newland.
"Craig" Reducing Mill for Copra, Palm Kernels, etc.
A short description of the machinery and processes for more scientific extraction of the oil may here be desirable.
In preparing ground-nut oil, the outer husk is generally removed, although oil can be expressed from unshelled nuts. Where native women and children are available this labour can be done by hand, but small hand machines are obtainable and more effective. Such machines break the husks between rollers set at such distance as to prevent the crushing of the kernels in the process; the husks and as much as possible of the red " skin " of the kernel being removed by a blast of air. The husks can be blown to the engine and used as fuel, or, mixed with meal, they may be made into cakes.
The cleaned kernels are ground between rollers, then placed in hydraulic presses. The first pressing takes place at ordinary temperature, yielding as much as 30 per cent, of pale-coloured oil. This ' cold-drawn ' oil is known as 'huile surfine' de Rufisque, Gambia, etc., according to the origin of the nuts. This is used for edible purposes. A further 6 or 8 per cent, of oil inferior in quality, but still useful for edible purposes, can be obtained by moistening and warming the cake in steam kettles at a temperature of 30° to 32° C. An additional 5 to 7 per cent, of oil, unfit for edible use, but very good for soap, can be obtained by a third expression at a temperature of from 48° to 50° C. The second and third expressions are usually made in open Anglo-American presses, which employ bags or cloths to hold the cake.
The following are approximate yields obtained from different kinds of ground nuts :-
Rufisque, ..... Gambia, .....
Mozambique, .... Bombay, ..... Coromandel, ....
Per cent. 31.5 31 31.5
Per cent. 45 to 46
42 to 45 37 to 38 36 to 37
The last three kinds are shipped decorticated, and consequently undergo changes rendering the taste in-different and the cake inferior. The cake left after the expression of the oil is a valuable feeding stuff for cattle and other animals.
The following analyses of various feeding cakes are stated below :-
Soya Bean Cake.
Crude fibre, .
Per cent. 11.6 5.70 7.17 28.50 28.06 18-97
Per cent. 13.75 4.60 6.56 24.62 29.28 21.19
Per cent. 12.7
5.05 11.07 38.82 26.51
In Senegal, where, with one set of six decorticating machines worked either by a locomotive or a portable engine, 5 tons of nuts in the shell were decorticated per hour, with the result that out of 280 tons treated 199 tons of kernels were obtained. This was so satisfactory that extensive plant is to be erected in various parts of the Senegal colony. Natives are also beginning to decorticate by hand, on account of the large pecuniary advantage to be gained. The company are also prepared to erect plant in Bathurst or other parts of the Gambia, and it is to be said that a saving of 50 per cent, in freight space is effected if the ground nuts be shipped after being decorticated.
The rate of freight should vary for the nuts in their different states. The difference in the freight would enable the trading firms to pay an encouraging price to the natives for decorticating nuts, and, as a conse-quence, the demand on shipping space would be greatly reduced, but if the idea is to be encouraged as it deserves, prompt steps should be taken by the Shipping Controller in order that they may materialise in time for the operations of the next crop, first to encourage the natives to decorticate the nuts, and secondly, to facilitate the installation of plant by the various firms to commence the decortication.
The yield of decorticated nuts per ton is :-8 cwts. of oil, 12 cwts. of cake, and that of nuts" in the shell is about 5 to 6 cwts. of oil, 8 cwts. of cake, 6 cwts. of empty shells (which have no nutritive value), and which are useful only as a combustible.
Decorticated nuts have been shipped from India for many years past. These generally reach Europe in poor condition, partly owing to faulty methods of decortication, causing damage to the kernels, and partly to the long voyage through hot regions. For the last few years decorticated ground nuts have been shipped from Northern Nigeria, and in spite of the rail journey to the coast of about 700 miles and a sea voyage of about three weeks, these reach Europe in good condition, and can be used for the production of edible oil of good quality. Ground nuts properly decorticated in Senegal should reach Europe in excellent condition, as the average distance of transport by rail would only be about 120 to 200 miles, followed by a sea voyage of ten to fourteen days, mostly in temperate regions. The chief points against the decortication of the nuts in the country of origin are (1) the demand for oil of high quality prepared from nuts shipped in the shell, and (2) the interference with the native custom of selling nuts in the shell.