This section is from the book "Practical Dietetics With Special Reference To Diet In Disease", by William Gilman Thompson. Also available from Amazon: Practical Dietetics with Special Reference to Diet in Disease.
Tapioca and cassava are made from the rhizomata of the Manioc utilissima or Manihot, a common plant in temperate and tropical regions. It is extensively grown in South and Central America, Africa, and the West Indies. Manioc flour forms the basis of food of the natives, and when made into bread and cakes it replaces the wheaten bread of Europe and North America. Cassava contains a poisonous juice that must be first drained off.
Tapioca, which is purified cassava, is made, like sago, by drying on hot plates, the clarified starch being first heated into a paste in large metal pans. It is an almost pure starch. The granules are not tough, and are very easily digested, so that they form one of the most useful of the amylaceous foods for persons with feeble digestion. Tapioca may be eaten alone in the form of puddings with cream or flavoured with lemon juice, wine, nutmeg, or other spice or aromatic, or may be used to thicken broths or soups. "Pearl tapioca " is a spurious article made from potato starch.
Air-dry tapioca contains 11.97 Percent of water. Water-free tapioca consists of: protein 0.79, carbohydrates 98.90, and ash 0.31 (C. D. Woods and L. H. Merrill).