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.
An ingenious and simple nut-cracking machine has been devised recently by J. O. Drews. It consists of a pair of finely corrugated steel jaws, one of which is fixed vertically to the frame of the machine, while the other is moved by means of a specially constructed cam. The moving jaw has its corrugated face formed at a slight angle to the face of the fixed jaw ; the space between the jaws is, therefore, wider at the top than at the bottom, so that larger nuts dropped between the jaws lodge near the top and small nuts near the bottom. In working, the moving jaw takes up three consecutive positions : (1) discharging, fully open, allowing the broken nuts to fall through ; (2) feeding, partly closed ; (3) cracking, a small auxiliary cam mounted on the main cam engages with the operating rod of the moving jaw, causing the latter to take a short, sharp movement and to crack the nut-shells without breaking up the kernels. The nuts are fed to the jaws by means of a sloping tray ending in a series of shaped bars mounted at right angles to and above the faces of the jaws. A series of -shaped bars mounted on a shaft rotate between the bare on the feed tray, pick up a row of nuts, and throw them between the jaws. The machine is light, simple, and strong, and seems to work well.
The working of another new palm-nut-cracking machine devised by Mr. Kent Johnston has been demonstrated recently in Liverpool. This machine works on the centrifugal plan, but differs from other centrifugal machines in that the nuts are flung from one ribbed rotating disc or drum into or against another disc rotating in the opposite direction. The machine is said to work satisfactorily, and weighs 130 lbs., being of convenient size for transport.
Every such effort to get the most out of kernels will probably be welcomed by merchant and native alike, especially as soap-makers and margarine-makers, and other users of kernel oil are calling for a contract in which kernels will be valued according to their oil con-tents, anything containing less than 48 per cent, of oil to be penalised.
Palm-kernel cake is the residue from the kernels of the nuts of the West African oil palm after expression of the oil.* More than one-quarter million tons of nuts have been for the past few years annually exported from West Africa, but until the outbreak of the war, and the consequent closing of the German ports, this huge trade was almost entirely in German hands. A small quantity of the nuts was imported into Britain, but almost all the cake left from the extraction of these was exported to the Continent, where it has always commanded a considerably higher price than in this country.
" Expression " is the more correct term when the material is crushed in a press and the oil squeezed out, " extraction " when oil is dissolved by suitable solvents (e.g., benzine). Solvent extracted oils are now used extensively for edible purposes.
As far back as 1861, at the Royal Agricultural College, Cirencester, it was experimentally established that kernel cake was good stuff for cattle, but the Germans discovered that palm kernel cake given to milking cows would increase the amount of butter fat by as much as over 1/4 per cent., so that by giving it to their cattle they were able to get as much butter from nine cows as before it took ten cows to produce. For that reason throughout the German Empire for many years palm kernel cake has been more valuable than it has been in England.
At the end of 1914 there were only two mills in Britain dealing with palm kernels, and their combined capacity amounted to only 70,000 tons per annum. Since then, however, a considerable development in this industry has taken place, and new mills (e.g., at London and Hull) have been erected capable of dealing with large quantities, so that, in the near future, very large stocks of palm-kernel cake will be at the disposal of the home feeder.
For the purposes of experiment, 2 tons of the cake were supplied by Messrs. Lever Brothers, Port Sunlight, who, in connection with their industry, crush a considerable quantity of palm kernels. These experiments have shown that palm-kernel cake is very highly digestible, and that its productive value is much higher than its chemical analysis alone would lead us to believe. For this reason three cakes were used in equal quantities throughout the experiment. For the purposes of the experiment, thirty head of cattle, eighteen heifers, and twelve bullocks, all cross-bred two-year-olds, were used. These were divided into three lots of ten each-each lot consisting of six heifers and four bullocks. For a (Messrs. Lever Bros.) short time before the commencement of the experiment they underwent a preparatory period of feeding, in order to accustom them to the experimental foods- Lot I. getting linseed cake, Lot II. decorticated cotton cake, and Lot III. palm-kernel cake. The cakes were fed in mixture with locust-bean meal, and were from the first taken readily by all the animals. The experimental period, which extended to eighty-four days, was divided into three periods of twenty-eight days each, the animals being weighed at the commencement, and again at the end of each period. The final conclusions reached were :"I. Fed in the same quantities, palm-kernel cake may be expected to give equally as good a return in live weight increase as linseed cake or decorticated cotton cake, and at present prices it gives a better monetary return than either of these.
Coconuts, Kernels, etc.- Capt. H. O. Newland.
Up-to-date Modern Machinery for dealing with Palm Oil and Kernels at La Societe des Huileries du Congo.
1II. Fed in mixture with locust-bean meal, it is taken readily by stock, and no difficulty need be experienced in storing cake containing a comparatively large percentage of oil."