(Sago; Saguslaevis, Rumph., et aliae fortasse Palmarum species. Caudicis Faecula, L.)
History.—Sago does not appear to have been known to the Greeks, Romans, or Arabians. The preparation of sago-meal and sago-bread, as carried on at Fanfur (Kampar, in Sumatra?), was first described by Marco Polo [Travels in the Eastern part of the World in the Thirteenth Century, translated from the Italian, with Notes, by W. Marsden, p. 614, 4to. Lond. 1818.] in the 13th century. Sago-bread was described and figured by Clusius. [Exotic, lib. i. cap. iii. p. 5, 1605.]
Granulated sago was not known until a later period. It is said [Steck, quoted by J. A. Murray, App. Medicam. vol. iv. p. 17, 1790.] to have been introduced into England in 1729, into France in 1740, and into Germany in 1744. Rumphius [Herbarium Amboin, pars 1ma, p. 64, Amst. 1750. "...... in Borneo ex eadem eonficiunt farina rotunda grana Coriandri semen magnitudine et forma referentia" I have given the words of Rumphius, because some highly respectable authorities (J. A. Murray and Guibourt) have overlooked this passage, and assumed that Rumphius does not mention granulated sago.] states that in Borneo grains of the size of a coriander seed are made from the farina of the Saguerus (Saguerus saccharifer, Blume).
The word sagu (also written by some of the earlier authors zagu and saga [See the authorities quoted in C. Bauhin's Pinax.]) is the Malay name both for the palm and its farina: [Crawfurd, History of the Indian Archipelago, vol. i. p. 387, 1820.] it is also used in Java to signify the bread made from the farina. [Sir F. Drake, in Hakluyt's Principal Navigations, Voyages, &c., vol. iii. p. 742.]
Commerce.—Sago is brought to England from Singapore in bags, &c. The quantity on which duty was paid in 1840 was 26,895 cwts.
Newbold [Political and Statistical Account of the British Settlements in the Straits of Malacca, vol. i. p. 301, Lond. 1839.] gives the following as the quantities imported into Singapore in 1836:—
|Sago from Sumatra||157750|
|Sago from West Side Peninsula||140|
|Sago from Borneo, 1308 piculs||140560|
|Sago from North Islands, 140 piculs||15251|
The quantity exported from Singapore in the same year was 28,764 piculs.
Manufacture. a. Of Raw Sago-Meal.—The manufacture of sago-meal varies somewhat in different localities. In the Moluccas, it is procured as follows: When the tree is sufficiently mature, it is cut down near the root, and the trunk subdivided into portions of six or seven feet long, each of which is split into two parts. From these the medullary matter is extracted, and with an instrument of bamboo or hard wood is reduced to powder, like sawdust. To separate the farina from the accompanying bran and filaments, it is mixed with water, and the mixture then strained by a sieve. The strained liquor deposits the farina, which, after two or more edulcorations, is fit for use. This is raw sago-meal. [Crawfurd, op. supra cit. vol. i. p. 300. Mr. Crisp (Asiat. Researches, vol. vi. 1799) has described the mode of preparing sago-meal in the Poggy Islands, lying off Sumatra. See, also, Forrest's Voyage to New Guinea, 2d edit. 1780, pp. 39-41, for the method of preparing it by the Papuans.]
b. Of Sago-Bread.—In the Moluccas, sago-cakes are made by throwing the dry meal into heated earthenware moulds: a hard cake is formed in a few minutes, so that one heating of the mould serves to bake several series of cakes. [Forrest (op. supra cit.) has figured a mould, which he calls the Papua oven.]
c. Of Granulated Sago.—To prepare this the meal is mixed with water and made into a paste, which is then granulated. Forrest says that in New Guinea granulated sago is made by mixing the sago-meal with water and passing the paste through a sieve into a very shallow iron pot held over a fire, by which it is made to assume a globular form; so that, he adds, our grain sago is half baked and will keep long. This, according to Blume, is the process which is followed by the Chinese colony in Singapore; the meal being first repeatedly worked and dried. Blume adds that, during the heating process, the grains are constantly turned, and that, though quite white at the commencement, they become hard and somewhat pellucid during the process.
One kind of pearl sago of the shops has been obviously subjected to some heating process: this is the Tapioka sago of Guibourt; but the application of heat must have been most carefully regulated, for charred sago is unknown to commerce. Some of the granulated sago of the shops presents no evidence of having been heated; and it has, therefore, been supposed that its granulation must have been effected by a mill.
Description of Sago.—Sago occurs in commerce in two states—pulverulent and, granulated.
1. Pulverulent Sago; Sago Meal; Sago Flour (Farina Sagi).—This is imported in the form of a fine amylaceous powder. It is whitish, with a buffy or reddish tint. Its odour is faint, but somewhat unpleasant and musty. Viewed by a powerful pocket-lens, it presents a glistening granular appearance. Examined by the microscope, it is found to consist of irregularly elliptical or oval, more or less ovate, usually isolated particles, which are often somewhat narrowed or tapered af one extremity. Owing to their mutual pressure, many of them appear as if truncated, either by a single plane perpendicular to the axis of the particle, in which they are more or less mullar-shaped—or by two inclined planes, giving the particles a dihedral extremity. Some of them resemble in form a caoutchouc bottle cut off at the neck. From their strong lateral shading they are obviously convex. Many of the particles are more or less broken. Most of them have an irregular or tuberculated surface, as if eroded. The hilum, when perfect, is circular; but it cracks in the form of a single slit, or of a cross, or in a stellate manner. The surface of the particles presents the appearance of a series of concentric rings or annular lines, which, however, are much less distinct than in potato starch. These lines are indicative of the concentric layers of which each particle is composed. When examined by the polarizing microscope, the particles show a black cross, the centre of which is the hilum. [The following measurements, in parts of an English inch, of the particles of starch of sago-meal, brown saga, and pearl sago, were made for me by Mr. George Jackson:—
|Sago-meal.||Brown Sago.||Pearl Sago.|
|Long diam.||Short diam.||Long diam.||Short diam.||Long diam.||Short diam.|
I have met with sago-meal in commerce under different names. Once, I received a sample from Cockermouth, in Cumberland, where it was sold as "Food for the People." A sample of a fine white and carefully-prepared sago-meal was given me under the name of arrow-root. I shall distinguish it as refined sago-meal.
The following information respecting the mode of refining sago-meal was furnished me by a starch manufacturer: "By sifting and washing, the best sago-meal loses about one-fifth of its weight in the form of earthy matter and woody fibre. The meal thus sifted and washed is then bleached by means of chloride of lime and sulphuric acid. The bleached meal is afterwards washed in successive waters until a perfectly pure product is obtained. In this state it serves as a food for infants and invalids. Coloured by turmeric, and flavoured by the essential oils of cassia and bitter almonds, it forms a custard powder. Without the colouring matter, it serves as a blanc-mange powder."
2. Granulated Sago; Grain Sago (Sagus granulosa); Grana Sagi.—The grains are more or less rounded masses of variable size and colour. Examined by a microscope with a low object-glass (say of 2- or 3-inch focus), they are seen to be masses of glistening particles. There are two kinds of granulated sago—brown sago, and pearl sago.
α. Common or Brown Sago (Sagus fusca); Sagou gris des Moluques, Planche and Guibourt.—This is the only kind of sago which was known in English commerce prior to the introduction of pearl sago.
It occurs in somewhat irregularly-rounded or globular masses or grains, which are whitish on one side, and grayish-brown on the other. The ordinary brown sago of the shops consists of grains which are usually about the size of the grains of pearl barley. This may be termed the smaller or ordinary brown sago. It is the sagou gris des Moluques of both Planche and Guibourt. But there is another variety, the globular masses of which are larger, sometimes as large as gray peas. To distinguish it from the smaller sort just mentioned, I shall call it large brown sago. I received it first from Dr. Douglas Maclagan, of Edinburgh, and subsequently from Professor Guibourt, who terms it gros sagou gris des Moluques. The smaller masses of it are about equal in size to the larger masses of the former sort of brown sago. Except in the size of the grains or masses, the two sorts are identical.
Examined by the microscope, the grains of brown sago are found to consist of particles like those of sago-meal, but somewhat more broken and less regular in their shape. Some of them present the appearance of containing in their interior a smaller particle, or rather, perhaps, an air-cavity, which, when examined by polarized light, forms the centre of the black cross. Intermixed with the starch particles is a yellowish-brown substance, which gives colour to the sago.
β. Pearl Sago (Sagus perlata).—The manufacture of this kind of sago is comparatively recent. Crawfurd, [History of the Indian Archipelago, vol. iii. p. 349, 1820.] who wrote in 1820, says: "Within the last few years the Chinese of Malacca have invented a process by which they refine sago so as to give it a fine pearly lustre. ... A small quantity of it, exposed for sale in the London market in 1818, sold for about thrice the price of ordinary [that is, brown] sago." The sago used by the Chinese at Malacca in the manufacture of pearl sago is, according to Newbold, [Political and Statistical Account of the British Settlements in the Straits of Malacca, vol. i. pp. 213-4, 1839.] brought from Sumatra. Pearl sago is also prepared at Singapore. [Blume, Rumphia, vol. ii. p. 148.]
Pearl sago occurs in pearl-like grains, which vary in size from that of poppy seeds to that of white mustard seeds, or even somewhat larger than these. The shape of the larger grains is more or less globular, that of the smaller ones being often much less regular. The surface of the larger grains is smooth, even, and regular; that of the small grains often rough, uneven, and somewhat tuberculated. Occasionally, two or three of the smaller grains adhere together. Some samples are white, some brownish yellow, pink, or roseate. The coloured grains are not of uniform tint over the whole of their surface; often being on one side white, on the other coloured. By the aid of a solution of chloride of lime, the coloured kinds can be bleached and rendered perfectly white (bleached pearl sago).
When submitted to microscopic examination, pearl sago is found to consist of the same kind of starch particles as sago-meal, but all more or less ruptured, and presenting indistinct traces of rings. These peculiarities are doubtless produced by the process of granulation.
αα. White Pearl Sago.—Grains smaller than white mustard seeds; opake and white on one side, pearly on the other. The filtered cold aqueous infusion does not strike a blue colour with tincture of iodine. The whiteness of this kind of pearl sago has probably been produced by bleaching.
ββ. Coloured pearl sago.—Grains of different size. Those of some sorts are not larger than poppy seeds (small coloured pearl sago), while those of other sorts are nearly as large, or even somewhat larger, than white mustard seeds (large coloured pearl sago). The colour varies in intensity, and slightly in shade also; but the prevailing tint is that of bran, or sometimes pinkish brownish yellow. Some sorts are as pale as ground, unsifted wheat-flour (pale-coloured pearl sago); others are nearly as deep-coloured as bran itself. Some of the larger sorts have a grayish or brownish colour (grayish or brownish pearl sago); but, like all kinds of coloured sago, the tint is not uniform on different parts of the same grain, being deep on one side and pale on the other.
The filtered cold aqueous infusion of some sorts does not strike a blue colour with tincture of iodine. This kind corresponds to the Sagou rosé des Moluques of Planche and Guibourt.
The filtered cold aqueous infusion of other sorts yields a blue colour on the addition of tincture of iodine, showing that a higher temperature has been employed in the preparation of it than of other sorts. This corresponds to the Sagou-tapioka or Tapioca-sago of Guibourt. When examined by the microscope, the particles are found to be more ruptured and torn—an obvious effect of heat on them. This sort of pearl sago is often not distinguishable by its external appearance from that of the Sagou rosé des Moluques of Planche and Guibourt.
Under the name of damaged pearl sago, I have received a sample of coloured pearl sago, some of the particles of which are yellow (from sulphur-yellow to orange coloured). When bleached by means of chloride of lime, it becomes quite white (bleached pearl sago).
Factitious Sago.—This is prepared in both Germany and in France (at Gentilly, near Paris) with potato-starch. It occurs both white and coloured.
I have two kinds of white factitious sago—one small-grained, the grains of which are scarcely so large as white mustard seeds; the other large-grained, the grains of which are intermediate in size between white mustard seeds and coriander seeds. The first, I met with in English commerce; for the other, I am indebted to Professor Guibourt.
I have also two kinds of coloured factitious sago, both large-grained—one red, [This is, perhaps, the kind mentioned by Planche (Journ. de Pharm, t. xxiii. p. 305, 1837) as being "falsified sago coloured by cochineal."] the other brownish, [This, perhaps, is the brown sort of German sago made from potato-starch, and said, by Dierbach (Synopsis Materiae Medicae, Abt. i. S. 37, 1841), to be coloured by burnt sugar.] and somewhat resembling brownish pearl sago. For both of these I am indebted to Professor Guibourt.
The white and the red sorts are remarkable for being spherical and smooth.
The microscope can alone distinguish factitious sago from the real sort. The difference in the size, the shape, and other characters, between the particles of sago-starch and the unaltered particles of potato-starch, readily distinguish the one from the other. (See also Potato-starch.)
But many of the starch particles of potato sago are ruptured by the influences to which they have been subjected during the preparation of the sago. They have become swollen, ruptured in the direction of their long axis, and, by drying, have shrivelled, leaving a long, linear, sometimes curved or even-branched line with incurved or involuted edges, indicating the situation of the rupture.
I have received from Professor Guibourt samples of "Sagou des Maldives de Planche, donné par lui," and "Sagou de la Nouvette Guinée de Planche, [Journ. d. Pharm, tom. xxiii. p. 155, 1837.] donné par lui," and find them to be fictitious sagos made from potato-starch. The grains of New Guinea sago are undistinguishable externally, and, by the microscopic examination of their starch particles, form red-coloured "Sagou de fécule de pomme de terre," also sent me by Professor Guibourt. Both are bright red on one side and whitish on the other. Most of their starch grains are ruptured and shrivelled as above described. The Maldive Sago is paler coloured, and some of its starch particles are little or not at all altered; others are ruptured and shrivelled.
Composition.—Sago has not been analyzed. The pure starch, of which it essentially consists, doubtless has the same composition as other amylaceous substances, viz., C18H10O10. Sago-meal is contaminated with various impurities (see ante, p. 164). Granulated sago contains some colouring matter, particles of which may readily be detected by the microscope.
Chemical Characteristics.—Sago possesses the general characters of an amylaceous substance.
Sago-meal is insoluble in cold water; but, by boiling in water, it almost entirely dissolves, and yields a tolerably clear solution. The decoction, when cold, strikes a blue colour with tincture of iodine.
Granulated sago swells up in cold water, but does not completely dissolve by boiling, a more or less considerable amount of insoluble matter remaining behind. The remarkable difference in the action of boiling water on sago-meal, and on different kinds of granulated sago, leads me to suspect that some substance of difficult solubility in water is used in the preparation of the paste for making granulated sago. The filtered cold aqueous infusion of some sorts of pearl sago (Sagou-tapioka of Guibourt) strikes a blue colour with tincture of iodine. The cold infusion of brown sago is rendered milky by nitrate of silver, diacetate of lead, and protonitrate of mercury; but the cold infusions of pulverulent and of pearl sago are scarcely affected by these tests.
Physiological Effects.—It is nutritive and easy of digestion, and is an important article of food in some parts of the East. "The Malay sago palm," says Dr. Roxburgh, "is the tree, the pith of which is the staff of life to the inhabitants of the Moluccas." It is probable that this pith contains some nitrogenized nutritive substance in addition to the amylaceous matter.
Uses.—Sago puddings are occasionally brought to table. But the principal use of sago is to yield a light, nutritious, easily-digestible, and non-irritating article of food for the invalid in febrile and inflammatory cases. For this purpose it should be boiled in water (in some cases milk is preferred), the solution strained, and flavoured with sugar and spices, or even with a little white wine, when the use of this is not contraindicated.