What exactly is tapioca? Where does it come from?
Tapioca is available in many different forms, but they all start out as the root of the cassava plant.
Cassava is well-known in South America and Africa as a good, reliable source of carbohydrates. In fact, because of its high drought-tolerance and ability to grow in low-fertility soils, cassava is the staple food of an estimated 500 million people. The roots can be harvested anywhere from six to eight months to three years after the cassava is planted, making it a good emergency supply of carbohydrates in times of drought or famine.
Unfortunately, the raw roots and leaves of the cassava plant can be toxic. The two general types of cassava plant are classified into sweet and bitter, and, not surprisingly, the bitter varieties contain much more of the toxic substance. The thing is, they are also generally higher-producing: that toxin -- a form of cyanide -- protects the plant from pests.
The bitter type is mostly used in the countries in which cassava is grown. Proper processing -- drying, soaking in water, rinsing or baking -- eliminates the risk. But, particularly during times of famine, shortcuts are sometimes taken in the processing, and that has been linked to cyanide-related health problems in developing countries.
The sweet varieties contain the toxin only near the surface of the root. After normal peeling and cooking, they're safe to eat.
Obviously, tapioca is already processed to the point where the toxin is totally removed. You can buy quick-cooking tapioca that's usually used as a thickener in fruit pies and sometimes soups and stews. Pearl tapioca, with larger granules, is often used to make tapioca pudding. Tapioca flour (also called cassava flour) is also available, mostly in specialty markets. As its name implies, it's finely ground and, unlike the other forms of tapioca, dissolves completely when used as a thickener. Granules in quick-cooking and pearl tapioca become clear and gel-like when cooked, but the granules don't dissolve completely.
Quick-cooking tapioca is tailor-made for thickening soups, stews or gravy in slow cookers, because it doesn't have to be stirred to prevent it from settling. Also, it can withstand long cooking times without breaking down. Similarly, dishes made with tapioca don't lose their quality when frozen and then reheated, because the tapioca retains its thickening capabilities throughout those processes.
Chow Line is a service of Ohio State University Extension and the Ohio Agricultural Research and Development Center. Send questions to Chow Line, c/o Martha Filipic, 2021 Coffey Road, Columbus, OH, 43210-1044, or filipic.3@cfaes.osu.edu.
This column was reviewed by Jaime Foster, registered dietitian and program specialist for Ohio State University Extension in the Department of Human Nutrition, College of Education and Human Ecology.
To receive a PDF file of Chow Line via e-mail, contact Martha Filipic at filipic.3@cfaes.osu.edu.