Cassava: A Lesson in Human Ingenuity!

Sometimes it amazes me that certain plants have become food! Cassava, for example, has been domesticated for 8-10,000 years. But cassava contains cyanogenic glucosides which become hydrogen cyanide. The cyanide combines with hemoglobin making it unable to carry oxygen to tissues.

Cassava was most likely first domesticated by people near the southern border of Brazil, however early evidence of its use in Central America has also been found.

Portuguese explorers found people using cassava as a staple when they visited South America. As the explorers participated in the slave trade, they introduced the crop to Africa in about 1550. From the slave trading stations near the mouth of the Congo River, cassava soon spread to all of central Africa. The Portuguese also spread cassava to East Africa, Madagascar, India, Ceylon, Malaya, and Indonesia by the 1700s.

image from blog.terramadre.org/index.php/kubrick/2006/09/P10/

The people found using cassava in South America were the Tupinamba. They processed the tubers into meal and bread using techniques similar to those still used today. These techniques remove the dangers from cyanogenic glucosides.

But how did the people figure this out? Human ingenuity? We may never know, but we can use their preparation techniques to protect ourselves from the dangers.

Peeling the tuber is the first line of defense because most of the cyanogenic glucosides are found in the tuber skin. Pulping the tuber is another method of detoxifying the cassava. In pulping, the peeled tuber is grated and crushed, pressing most of the water and toxins out of the pulp. Boiling can also remove the toxicity.

Cassava varies in bitterness depending on growing conditions and the genetics of the individual plant. Higher contents of cyanogenic glucosides correspond to more bitter tasting cassavas.

Amounts of cyanogenic glucosides in cassava are:
–Sweet Cassava 40-130ppm
–Non-Bitter Cassava 30-180ppm
–Bitter Cassava 80-412ppm
–Very Bitter Cassava 280-490ppm
where ppm is parts per million and concentrations less than 50 ppm are considered safe.


Most cassava tubers sold in grocery stores in the United States is sweet cassava. Bitter cassava is often processed into flour, with the toxins removed during processing. However, in some tropical nations some people eat bitter cassava if they have no other food. These people can suffer neurological disorders and other problems if they do not prepare the cassava properly. Over 500 million people in the world depend on cassava as their main calorie source.


More information about cassava can be found at
http://researchnews.osu.edu/archive/cassava.htm and

http://quazen.com/recreation/food/how-garri-is-produced-from-cassava/2/#ixzz13W64kAfb