Arrowroot, a name loosely applied to the starch extracted from a number of roots and grains, as the maranta, manihot, tacca, arum, potato, etc. It was originally limited to the starch of the maranta arundinacea, a plant which grows in the East and West Indies, and which was considered a specific for the wounds caused by poisoned arrows. It is a simple food, in high repute for invalids. Not containing nitrogen, it is well adapted for producing fat and promoting the warmth of the body. According to Liebig, 4 lbs. of it contain as much carbon for supplying animal heat by its combustion as 15 lbs. of animal flesh. In its preparation the tubers are mashed, and the pulp is soaked in water. This dissolves out the starch, which is separated from the fibre by straining. After settling, the clear water is drawn off, and the starch washed with fresh water and again allowed to settle. It is finally dried in the sun.
The most common adulterations are with the cheap potato starch, sago, and manioc or tapioca, all which can be detected by the micro-scope. The granules of the potato are of very irregular, ovoid, and truncated forms, and of various sizes, from 1/200 of an inch in diameter, while the particles of the arrowroot are very regular ovoid forms, and of nearly equal sizes. Dilute nitric acid is also a good test. When triturated with it in a mortar, arrowroot changes into an opaque paste, which is some time in becoming viscid; but potato and flour starch thus treated form immediately a transparent, thick paste. From the inferior starches alcohol extracts an unwholesome oil of disagreeable odor, but none from arrowroot. The composition of the fresh root was ascertained by Benzon to be in 100 parts as follows: volatile oil, 0.07; starch, 26; vegetable albumen, 1.58; a gummy extract, 0.6; chloride of calcium, 0.25; insoluble fibrine, 6; and water, 65.5. Of the starch 23 parts are obtained in the form of powder, and the other 3 are extracted in the form of paste from the parenchyma with boiling water. - There is a so-called arrowroot brought from Florida, derived from a plant allied to the sago palm, and sometimes known as coontie. The plant grows among the everglades in great profusion.
It is of an inferior quality, containing only 12 per cent. of starch.
Florida Arrowroot (Coontie) and Fruit.