The starch separated from the grain.
Habitat. S. America; cultivated in warm temperate zones.
Syn. Corn, Indian (Turkish) Corn, Maize, Mealies, Guinea (Turkey) Wheat; Amyl., Corn Starch; Fr. Mais, Fecule (Amidon) de Maize; Ger. Mais, Amylum Tritici, Weizenstarke, Starke, Kraftmehl, Maisstarke.
Ze'a. L. fr. Gr.
to live - i. e., from its life-supporting properties to beast and man.
Ma'ys. L. maydis, Sp. maiz, fr. mahiz, its native name in the Haitian Island language, its native habitat.
Am'y-lum. L. starch, Gr.
= a, not, +
a mill - i. e., so fine as not requiring to be ground in a mill.
Starch, fr. stark, strong, stiff, so called from its use in stiffening various substances.
Plant. - An annual; stem 1.2-4.5 M. (4-15°) high, erect, stiff, unbranched, grooved on one side, smooth, solid, with spongy centre, jointed; roots fibrous; leaves many, linear, .6-1 M. (2-3°) long, 5-7.5 Cm. (2-3') wide, channeled; flowers monoecious - staminate spikelets numerous, in pairs, forming a long-stalked terminal panicle (tassel), - pistillate thick spikes, from the husks of which project long, slender styles and stigmas (silk); fruit, caryopsis (kernel) and rachis (cob) form the spike (ear), which is enclosed by the bracts of the spathe
Fig. 22. - Zea Mays: a, spadiceous flower with styles protruding; b, the same freed from cover leaves reduced in size; c, a single style with stigma.
(husks). Kernels (seed, grain) occur in 8-10-12 rows, or some even number - yellow, white, red, purple; styles and stigmas (once official under the name of Zea - fluidextract (dil. alc.)), a matted mass of slender filaments, thread-like, 5-15 Cm. (2-6') long, .5 Mm. (1/50') thick, yellowish, brownish. Starch, in fine powder, irregular, angular, white masses, consisting chiefly of polygonal, rounded, spheroidal starch grains, .003-.035 Mm. (1/8325-1/5000') broad, usually with lenticular, 3-4-rayed central cleft (rounded - circular marking); insoluble in cold water, alcohol inodorous; taste slight, characteristic. Tests: 1. With iodine T. S. - deep blue. 2. Boil 1 Gm. with water (15), cool - translucent, whitish jelly. 3. Incinerate .5 Gm. - ash .5 p. c.; aqueous mixture neutral. 4. With diluted acids or diastase - dextrin, C12H20O10, dextrose, C6H12O6, water, H2O, which reveals the starch formula to be (C6H10O5)3. Solvents: water, glycerin - boiling. Dose, 3ss-2 (2-8 Gm.).
Commercial. - Starch is prepared from the grain by soaking in hot water, to which an alkali sometimes is added, until the testae are
Fig. 23. - Corn starch.
softened, then grinding under water and washing it upon large sieves with water; by this means the starch is suspended in the water and will deposit upon being allowed to remain undisturbed for some hours; the gluten when present remains in the supernatant alkaline water or Upon the sieve. When all the starch is deposited on the bottom of the container (tank), the liquid is racked off, the starch cut into blocks and carefully dried in suitable chambers. The finely ground corn meal may also be kneaded under a stream of running water until milkiness ceases, then allowing the milky water to subside.
Constituents. - C6H10O5, or a multiple of this, ash 1 p. c.
Preparations. - 1. Glyceritum Amyli. Glycerite of Starch. (Syn., Glycer. Amyl., Plasma, Glycamyl; Br. Glycerinum Amyli, Glycerin of Starch; Fr. Glycere d'Amidon, Glycerat simple (d'Amidon); Ger. Unguentum Glycerini, Glycerinsalbe.)
Manufacture: 10 p. c. Triturate, until homogeneous, starch 10 Gm. with water 10 Ml. (Cc.), add this gradually to hot glycerin 80 Gm., continue heat, constantly stirring, at 140° C. (284° F.) until translucent jelly is formed.
Unoff. Preps.: Iodized Starch (Amylum Iodatum), 95 p. c, + iodine 5, + little distilled water - bluish-black powder, dose, 3j-4 (5-15 Gm.). Paste, Poultice, Water.
Properties. - Nutritive, demulcent, protective, absorbent.
Uses. - Mostly externally as a dusting-powder to allay itching and burning of the skin in erythema, urticaria, erysipelas, smallpox, to saturate bandages for fractures, as an injection for inflamed rectum or bladder, as a vehicle for enemata, to harden pills, antidote to iodine-poisoning. Owing to starchy foods fermenting they should be avoided in fermentative dyspepsia.
While the official starch is a product from corn, hence called corn starch, it should be borne in mind that there are many plants that also yield starch, but each kind peculiar to itself. This should not be accepted to infer total physical and chemical difference, because these in the main are uniform. It is only in the shape of the starch granules as viewed under a microscope that we recognize a varying form, and that this is characteristic alone for the source whence derived. Thus, when given a starch or mixture of starches, a small portion moistened with water and viewed under high power readily reveals its origin by the various outline granules. In this way (from their contained starch) it is possible to distinguish many official roots, rhizomes, seeds, fruits, etc., as it is also the cereals, edible fruits, and vegetables.
I. Wheat Starch (Agropy'ron (Trit'icum) cesti'mim). U. S. P. 1880. Lenticular, large and small granules, layers indistinct, hilum slight, near the centre.
II. Potato Starch (Sola'num tubero'sum). Ovate, granules unusually large, layers very distinct, hilum rather small and at the narrow end.
III. Maranta Starch (Maran'ta arundina'cea). Ovate granules layers delicate, distinct, hilum at the broad end, often cleft.
IV. Corn Starch (Ze'a Ma'ys). Polyhedric granules, layers not easily distinguishable, hilum central, large.
V. Oat Starch (Ave'na sati'va). Polyhedric granules often united in ovoid masses (compound), layers and hilum indistinct.
VI. Rice Starch (Ory'za sat'i'ra). Polyhedric granules, uniform, similar but much smaller than corn starch, hilum very small.
Fig. 24. - Starch granules, magnified 475 diameters.
VII. Bean Starch (Phase'olus vulga'ris). Ellipsoidal granules, layers distinct, crossed by fissures radiating from centre.
IX. Tapioca. Brazilian Arrow-root [Man'ihot Manihot (utilis'sima)]. Cassava Starch. Muller-shaped, layers indistinct, hilum near rounded end, often cleft.
X. Sago. Pearl Sago (Metrox'ylon Rum'phii and M. Sa'gu). Ovate granules, 1 end truncate, layers more or less distinct, hilum at rounded end, often cleft.
XI. Sarsaparilla Starch (Smi'lax officina'lis). Roundish, compound, usually with cleft hilum.
1. Dextrinum, Dextrin, C6H10O5. Obtained by heating starch 204° C. (400° F.), in a cylinder or flat vessel; this yellowish product is often called in commerce British Gum; may also make it by heating starch 110° C. (230° F.), with diluted nitric acid. It is a pale yellow, amorphous, gummy mass, soluble in water, insoluble in alcohol or ether; dextrinum album - mixture of soluble carbohydrates, amylo-, achroo-, erythro-, malto-dextrin, unconverted starch; pasta dextrinata, 33 p. c, + glycerin 33, water 34.