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.