The Production and Uses of Cotton-seed Oil.
By P. L. Simmonds, F.L.S.
I think I may claim the merit of having first suggested the production of cotton-seed oil. Forty years ago, in a course of lectures I gave before the Society of Arts and Manufactures in London, on "The Utilization of Waste Products," I mentioned, among other waste products, cotton seed, which was then an incubus cotton cultivators did not know how to get rid of.
The Council of the Society of Arts awarded me their silver medal for my valuable suggestions, and subsequently elected me a life member under one of their rules, in consideration of being eminent in the application of abstract science to the Arts, Manufactures and Commerce.
These lectures I afterwards expanded into a volume, under the title of "Waste Products and Undeveloped Substances," which went through several editions and is now out of print. I have reason to believe that the adoption of many of my suggestions has resulted in fortunes to some, and has utilized profitably much of the former waste in manufactures.
The Science and Art Department employed me to form a collection of waste products and their utilization, with a descriptive catalogue, which is now placed in the Bethnal Green Museum.
I had also to make a similar collection for the Austrian Government at the Universal Exhibition, held in Vienna in 1873.
To return to cotton-seed oil. At the time my suggestion was made of utilizing cotton seed for oil in 1855, the United States production was less than 1,250,000,000 pounds; now the production has risen to about 3,500,000,000 pounds. The first shipment of cotton-seed oil in the year ending June, 1872, was but 547,165 gallons, and few would have anticipated it would reach, in 1892, the enormous export of nearly 14,000,000 gallons, worth nearly $14,000,000. The various forms of cotton seed all yield good oils capable of being refined for dietetic use.
The oil possesses excellent lubricating qualities, and is useful for soap-making and for lamps. The quantity of oil produced, even in England, is large, the imports of cotton seed exceeding, in some years, 400,000 tons.
In the States the production of seed exceeds 3,000,000 to 4,000,000 tons, of which half is available for oil; 100 pounds of seed will yield two gallons of oil. There are four qualities of oil made. The crude oil is of a dirty yellow to reddish color; on standing it deposits a slimy sediment. The second quality has a pale orange color, and is obtained by refining the crude oil with a solution of caustic soda. The yellow oil resulting from this process is further purified by being heated and allowed to settle again, or by filtration, and is called "yellow summer oil." "Winter yellow oil" is made from the above material by chilling it, until it partially crystallizes, and separating the stearin (about 25 per cent.) in presses, similar to those used for lard.
This is then treated with fuller's earth in a tank, which holds back the coloring matter, and the oil which issues from the filter press is almost white.
In 1893, there were probably 1,250,000 tons of cotton seed crushed in the United States. From this seed there were obtained 1,000,000 barrels of oil. It is estimated that 300,000 barrels were used in Chicago for making oil lard; and St. Louis, Kansas City and Omaha took 200,000 for the same purpose. About 250,000 barrels went to Holland for making margarine, and large quantities to Southern Europe for mixing with olive oil.
Cotton-seed oil appears to be useful for table purposes, and it is desirable that its use in the pure state, rather than as a mixture, should be encouraged. It ought, however, to be sold on its merits, and with the addition of some qualifying term, which will indicate its origin.
This oil has entirely replaced olive oil in America, and there is scarcely a restaurant in London or Paris in which this new "salad oil" has not taken the place of the old Lucca product. In Portugal every means are now taken to prevent the sophistication of olive oil with cotton-seed oil, or passing it off as a food oil of the same value as olive oil.
For pharmaceutical purposes cotton-seed oil cannot be regarded as a good substitute for olive oil. It saponifies with difficulty as a drying oil, and the coloration which it gives with nitric acid shows that if used for any preparation liable to oxidation it may give curious results. The density of crude cotton-seed oil is 0.920 to 0.933, and when refined 0.925 to 0.930.
To distinguish cotton-seed oil from olive oil, take pure, colorless nitric acid of the density of 1.40 and mix it with half the quantity of oil in a test tube, closed with gum. After shaking it for several seconds, allow the tube to rest in a vertical position for five or six minutes. If the oil is from olives, the liquid is at first pale or colorless, changing to an ashy gray, with a slight yellowish hue. On shaking, a coffee-brown color will be seen if cotton-seed oil is present. The reaction is delicate enough to detect an adulteration of 5 per cent. of cotton-seed oil.
The shipments of cottonseed oil from the United States have progressed as follows in decennial periods:
With the extended production of cotton in various countries—India, China, Egypt, Brazil and the United States—a great future awaits cotton-seed oil. Some idea of the magnitude of the future may be formed from the fact that British India produced in 1889 a little over 9,000,000 cwt. of cleaned cotton; that amount must have been obtained from 27,000,000 cwt. of seed. Allowing half this to be required for home consumption and seed for next crop, over 6,000,000 cwt. of seed should have been available for export, whereas the export of seed has hitherto seldom reached 37,000 cwt. This year the export of seed will be larger, as for the nine months already expired, nearly 89,000 cwt. has been shipped. The weight of seed may be estimated at three pounds for every pound of cleaned cotton.