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Maranta

arrowroot, any of several species of the genus Maranta, members of the family Marantaceae, the rhizomes, or rootstocks, of which yield an edible starch. The most commonly used species is M. arundinacea, the source of genuine, or West Indies, arrowroot. This herbaceous perennial, a native of Guyana and western Brazil, is cultivated throughout the West Indies, Southeast Asia, Australia, and South Africa. Its creeping rootstock has fleshy tubers (underground storage organs), and its many-branched stem, reaching a height of 1.5 metres (5 feet), bears numerous leaves, having long narrow sheaths and large spreading ovate blades, and a few short-stalked white flowers. Plants are harvested when the tubers are gorged with starch, just before the plant’s dormant season. The roots are peeled and then grated in water. The resulting mixture is dried to a powder and purified by several washings.

Arrowroot starch supplies no vitamins and contains only 0.2 percent protein. In cookery, it is used as a thickener in soups, sauces, puddings, and desserts. When boiled in water, it yields a transparent, odourless, pleasant-tasting jelly. Its fine texture allows cooking at lower temperatures and for shorter periods than other starches, making it especially suitable for such egg preparations as custards, which are adversely affected by overcooking. Arrowroot is easily digested and is used in diets requiring bland, low-salt, and low-protein foods.

The name arrowroot is sometimes applied to starches obtained from other plants and used as substitutes for true arrowroot. Tous-les-mois, or tulema arrowroot (Canna coccinea), is another West Indies plant and produces a larger-grained product. East India arrowroot is a product of several species of the genus Curcuma, of the family Zingiberaceae, chiefly C. angustifolia, native to central India. Brazilian arrowroot, from the cassava plant (Manihot esculenta), is the source of tapioca. Tacca, or Otaheite arrowroot, comes from the pia plant (Tacca pinnatifida) of the South Pacific islands. Portland arrowroot, once manufactured in Portland, Dorset, England, is derived from tubers of the common cuckoopint (Arum maculatum), and other Arum species are important food starch sources in hot countries. Potato farina, sometimes marketed as British arrowroot, has been used to adulterate more costly preparations.

Venus's-flytrap. Venus's-flytrap (Dionaea muscipula) one of the best known of the meat-eating plants. Carnivorous plant, Venus flytrap, Venus fly trap
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starch, a white, granular, organic chemical that is produced by all green plants. Starch is a soft, white, tasteless powder that is insoluble in cold water, alcohol, or other solvents. The basic chemical formula of the starch molecule is (C6H10O5)n. Starch is a polysaccharide comprising glucose monomers joined in α 1,4 linkages. The simplest form of starch is the linear polymer amylose; amylopectin is the branched form.

Starch is manufactured in the green leaves of plants from excess glucose produced during photosynthesis and serves the plant as a reserve food supply. Starch is stored in chloroplasts in the form of granules and in such storage organs as the roots of the cassava plant; the tuber of the potato; the stem pith of sago; and the seeds of corn, wheat, and rice. When required, starch is broken down, in the presence of certain enzymes and water, into its constituent monomer glucose units, which diffuse from the cell to nourish the plant tissues. In humans and other animals, starch from plants is broken down into its constituent sugar molecules, which then supply energy to the tissues.

Most commercial starch is made from corn, although wheat, tapioca, and potato starch are also used. Commercial starch is obtained by crushing or grinding starch-containing tubers or seeds and then mixing the pulp with water; the resulting paste is freed of its remaining impurities and then dried. Aside from their basic nutritional uses, starches are used in brewing and as thickening agents in baked goods and confections. Starch is used in paper manufacturing to increase the strength of paper and is also used in the surface sizing of paper. Starch is used in the manufacture of corrugated paperboard, paper bags and boxes, and gummed paper and tape. Large quantities of starch are also used in the textile industry as warp sizing, which imparts strength to the thread during weaving.

Slices of lemon pie topped with meringue.
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The Editors of Encyclopaedia BritannicaThis article was most recently revised and updated by Melissa Petruzzello.