THE POTATO: ITS COMMERCIAL PRODUCTS. (FROM THE "MARK LANE EXPRESS.")

Daily Southern Cross, Volume XVII, Issue 1438, 24 September 1861, Page 4

THE POTATO : ITS COMMERCIAL PRODUCTS. (FROM THE "MARK LANE EXPRESS.")

The potato products, and their economic uses, with the industries they evoke, are more extensive than may ba generally supposed by those who have considered the tuber only in its food aspect, as it appears as an edible at our own dinner-tables. The preparation and application of many of its subsidiary products are certainly not so generally known as might be desirable. Of all our root crops none is more valuable than the potato. It affords nutritive food to man and beast, and is> one of the most important contributions to the Old World which the discovery of the New gave. It is considered by political economists, next to wheat, of the greatest importance as human food, leaving out of view the circumstance that in times of scarcity it affouls food fully three months earlier than the cereal grains. As an adjunct to other food the potato is beyond all praise ; but as the chief article of consumption, and sole dependence of the inhabitant of any country, it becomes politically and economically a curse. It seems certain that the potato, when relied upon as the sole subsistence of a community, exposes it to more casualties thanpiobably any other cultivated plant which forms a natural diet. As a proof of the wide range of excess and failure of ciop to which the potato is subject, it may be mentioned that in years of scarcity it has been known to be ten times as dear as in seasons of plenty ; whereas the range of wheat does not exceed two, or at the most three times its average rate in modern cultivation. The potato, which is an annual, represents in the tubers developed from the stem the perennial part of a plant. Like all annuals, the potato exerts its chief efforts in developing flowers or fruit ; and it has the power of limiting the period of development when the extent and power of the roots are increased. The potato differs from all those plants which are cultivated for economical purposes in Europe, and can only be compared to those orohideous plants which yield salep, and are not yet cultivated among us. The tubers both of the potato and of the salep plants are nutritious, and agree in this — that in the cells of the tubers grains of starch, with more or less azotised mucilage, are collected ; while the cell walls possess the remarkable property of swelling up into a jelly, and thus becoming easily digestible when boiled with water. But while the tuber of salep coutains only one bud or germ, the potato usually develops several, often many germs. The potato plant continues to form tubers until the flowers appear, after which it is employed m ripening those already formed. Not a portion of the potato but is subservient to the welfare and convenience of man. Its green tops are good, boiled as spinach, and from its leaves and flowers Dr. Latham extracted an anodyne medicine. The blossoms yield a very beautiful yellow dye. From its stems is obtained in Austria a soft and useful flax, and if burned they yield a good deal of potash. The haulm or stems of potatoes hare often been patented as a paper-making material, and so has the fibrous pulp of the root. The extension of potato cultivation has been particularly *apid during the present century, not only in Great Britain and Ireland, but in Europe and North America. Potatoes are now very largely cultivated in Prance, Italy, and Germany ; and, with the exception of the Irish, the Swiss have become their gieatest consumers They were intioduced into India in the close of the last century, and are now successfully cultivated in Bengal and Madras, Java, the Philippines, and China. But the potato does not thrive within the tiopics, unless it be raised at an elevation of 3000 or 4000 feet above the level of the sea ; &o that it can never come into very general use in those regions. The Swiss early grew the potato among their mountains, and had soon learnt the art of drying and grinding them into flour, and making them into bread. A traveller, in 1730, relates that the mills oi Untersen had scarcely anything to grind but potatoes. The New Zealander owes his potato to England and his koo-mur-ra, or sweet potato, probably also to other foreigners ; although, as Captain Cook noticed plantations of the latter, they may have been indigenous. Potatoes are not so much used for food in the United States as in Europe, yet the crop raised over the whole cjuntry appears to be very great, propably 150,000,000 bushels yearly. The yield there vanes from 50 to 250 bushels per acre. So rapid an extension of the taste for, and the cultivation of, an exotic has no parallel in the history of industry; it has had, and will continue to have, the most powerful influence on the condition of mankind. The potato can be cultivated on a small as well as a large scale ; is, under eveiy system of agriculture, a beneficial object, and produces more nutriment upon the same extent of ground than any other plant cultivated in the temperate regions. It may thus be regarded as the plaintain of the temperate zone. The potato now forms a great part of the food of the inhabitants of Europe ; and its introduction as a supplementary crop has gieatly lessened the hazards ur famine. It would not be very far wrong to estimate the consumption of potatoes in the metropolis at lib. for each adult per day, whichfor an adult population of 2,000,000 would give a yearly consumption in London alone of 326,000 tons. The average imports into the United Kingdom fiom the Continent, &c , have been sis high in some years as 86,100 tons, but the average imports of the past four years have been 48,000 tons. The comparative yield of potatoes of course depends much on soil, season, care in cultivation, and other points. Mr. Knight, when president of the Horticultural Society, obtained, by careful experimental culture, thirty-four tons to the acre. In many parts of Scotland, twenty-four tons per acre have been raised An American author of repute affirms, on good authority, that 4000 bushels of potatoes have been grown in Germany on five acres of land. In the State of New York, 250 to 460 bushels of potatoes have been on an acre ; the bushel being taken at 641b5., this is over thirteen tons to the acre. Nearly 300 varieties of the potato are now grown in this country, besides many peculiar to America and the continent. A new variety, called the " peach-bloom potato," has recently been brought into notice in the United States, which combines great productiveness with excellent quality. The average yield of this variety is said to be 205 to 300 bushels per acre. We occasionally see mention made of potatoes raised of the gross weight of 41bs. and upwards. No doubt such large potatoes would gladden the sight of many an agriculturist who prefers to convert his potatoes into flesh before he seeks a market for his industry, but they would not be readily saleable for table use. It is a mistake to seek to grow monster potatoes for sale at market. The potato, like the turnip, the carrot, the cabbage, and the beet, to be fit for human food, must be of moderate size. In form, the nearer Ihe potato approaches the shape of an egg, and the less the number of eyes or tendencies to irregular contour, the better. It should not exceed a pound in weight, and be of a dry mealy flavour and quality. The composition of the potato has often been made the subject of chemical investigation. The existence of starch in the tuber was discovered about the middle of last century. The diflerent varieties of potatoes contain the same ingredients, but the proportions vary considerably. The quantity of water ranges from 73 to 81 per cent. ; of starchy fibrine from 6to 8 per cent ; of pure starch from 9 to 15 per cent. ; and of gum from 3 to 4 per cent. ; while small proportions of vegetable albumen, acids, and salts make up the remainder of the bulk. Besides its ordinary use as human food, the potato is employed in rearing live stock and in distillation. It 3 fecula, wanting gluten, does not undergo the panary fermentation, but it may be so mixed with wheat flour as to produce good bread, and it is applicable to other purposes of domestic economy, while the use of its starch is extending in various forms. The results of examination, on the comparative yield of starch in the potato, show that, while it abounds towards the latter part of the season, it decreases when the tubers begin to germinate in the spring. It was found that 2401b5. of potatoes taken from the ground contained of stareh —

The quantity of starch remained the satne during the dormant state of winter, but decreased vrhenever the plant began to grow, and to require a supply of nour ishment. The manufacture of starch from potatoes is carried on to a very Urge extent in France, not less than 27,000,0001b5. being produced* there annually. From 50, 000 to 60,000 tons of potatoes are used for this purpose in the neighbourhood of Paris. In this country, also, potato starch has of late been manufactured in considerable quantity, and sold for food under a variety of imposing names. Some of the starch sold as Indian corn starch is merely potato starch with various slight additions to impart a flavour. The potato flour and English arrowroot, met with in many Italian warehouses in London, is the same substance. Potato starch may be known from true arrowroot by rubbing a httte of it between the finger and thumb, when it will be observed that the potato starch is softer to the touch, and more shining to the tight, than arrowroot. Tho microscope is, however, the most important agent in distinguishing the diffeient starches from each other ; and by it we can readily detect potato starch. We recognUe it by the size, shape, and structiue of its grains, and the numerous concentric rings visible on its »urface. Though the size varies somewhat, yet on the average it exceed* that of other commercial starches, always excepting tow* let moit, whose grains are usually

rather larger. The actual size of the grains varies from l-500th to l-80th of a line in diameter. The shape of the larger particles is ovate. The quantity of starch obtained from potatoes, as we have already shown, is subject to considerable variation.

All starch in potatoes is confined very near the surface ; the heart contains but little nutriment ; indeed is often hollow and transparent. Ignorance of this fact may form a plausible excuse for those who cut off thick parings in preparing for cooking, but none to those who know better. Chculate the injunction — '• Pare thin the potato skin." In manufactories the maximum quantity of starch obtained rarely exceeds eighteen per cent. ; and it deserves especial notice that frosted potatoes yield as much fecula, as those which aie unhosted. The nutritious matter of the potato may be preserved in a dry state by washing the tubers well in water, then subjecting them to the teinpoiary action of steam, by which the skins are readily detached, and finally shcing them into thin pieces, drying them, and giinding the whole into a powder. Of this bread may be made by an admixture of wheaten flour or oatmeal. Thiee qualities of potato meal are obtained in grinding — fine, middle, and black ; 1 pound of bran or refuse is obtained fiom 12 of meal. The manufacturers of potato starch in Germany adopt a very simple process for determining the qualities of their potatoes. They piepare » solution of salt of certain density, into which they throw the potatoes ; all those which float are considered to watery to be profitably used in the manufacture of starch, and are i ejected. By taking a number of vessels, and partially filling them with solutions of salt of different densities, and then successively intioducing the roots into one vessel after another, until a solution is found in which they nearly float, we can ascertain in a. rough way its relative quality when complied with another root. The potato Btarch when sepaiated fiom the pulp and dried, has still a peculiar rank taste, which renders it disagreeable for food. To remove this nauseous odour and taste, it is washed with a weak solution of carbonate of soda, which renders it perfectly sweet. Besides its application in the manufactuie of artificial tapioca, sago, and vermicelli, &c, it is also used in large quantities in print works, for thickening colour and finishing goods, and also as a substitute for wheaten staich in laundry purposes.

iidney potato, is 2 Potato varieties — Shaw's Champion Chair-rouge L'Orpheline 28 to 32 (Dr. Peaison. 18-8 (Vauquelin.) 15-9 12-2 24-2

The proportion in 100 parts of the

lbs. lbs. per cent. [n August 23 to 25 or 9 6 to 10"4 September ... 32 ... 38 ... 133 ... 160 October 32 ... 40 ... 13-3 ... 16"6 November ... 38 ... 45 ... 16-0 ... 18'V April 38 .. 28 .. 16-0 ... 11-6 May 28 ... 20 ... 11-6 ... 8-3