Arrowroot is an easily digested starch extracted from the roots of the arrowroot plant, Maranta arundinacea. The starch is used as a thickener in many foods such as puddings and sauces, and is also used in cookies and other baked goods. It is extremely bland, making it suitable for neutral diets, especially for people who are feeling nauseous. The starch is not terribly nutritious, but some people believe that it helps to soothe upset stomachs, which is why many health food stores carry arrowroot cookies.
The arrowroot plant is native to the tropics of South America. It has a long history of cultivation by native peoples, who developed an extensive treatment process for extracting the usable powder from the roots. The roots are washed, scraped, beaten, soaked, pulped, and finally forced through a sieve. The liquid and fine powder which make it through the sieve are dried, leaving the useful arrowroot powder behind.
When Europeans first encountered arrowroot, the Arawak Indians informed them that it was called aru-aru, “meal of meals.” The Indians placed a high value on the root as a food, and the Europeans duly brought it back with them along with numerous other unusual plants and animals. Arrowroot was also used medicinally, with some Indians believing that it should be placed on wounds made with poisoned arrows to draw out the toxins. The Europeans may have begun calling it arrowroot because of the perceived medicinal properties, or they may have simply corrupted aru-aru.
In some stores, this starch is sold as arrowroot flour. The powder should be fine and white, similar to cornstarch. Some manufacturers adulterate it with other starches, so consumers should make sure that they are purchasing pure arrowroot, since these other starches may behave differently in the kitchen. The powder should be mixed with a cool liquid before being introduced to a recipe, and it should be added towards the end, since overcooking can destroy its gelling properties. Unlike many starches, arrowroot turns clear as it sets, and will not interrupt the color of dishes it is included in.
In some stores, arrowroot can be found in the form of a fresh whole root, labeled as Chinese potato or tse goo. The whole root can be processed to extract the powder, but it can also be used in recipes. The papery layer should be peeled off before the root is boiled or fried, and cooks should remember that it is relatively bland.