Manihot esculenta

Cassava, manioc, tapioca

Family Euphorbiaceae

Manihot esculenta, cassava, manioc, tapioca (M. esculenta 1), is a shrub, 1-5 m high, with latex in all parts and edible tubers, which develop as swellings on adventitious roots. The leaves are very variable in size, colour of the petioles (M. esculenta 2), and number and depth of lobes. The pale yellow and unisexual flowers (M. esculenta 3) are borne in axillary racemes; the male ones 5-10 mm long with 10 stamens in 2 whirls, the female ones 10-25 mm long containing an ovary with 3 stigmas. The fruit is a globose capsule, 15 mm long, containing 3 seeds. Propagation is done with stem cuttings.

Distribution
Cassava is not known in a wild state. It is likely that the crop was grown in Peru in prehistoric times and in Mexico since the beginning of our era. The Portuguese probably took it to West Africa in the second half of the 16th century. In 1736 it was taken to Reunion and Madagascar, and it was recorded in Zanzibar in 1799. However, Speke did not notice cassava in East Africa in 1862, but Stanley reported it from Uganda in 1878. It was taken to Sri Lanka in 1786 and reached Bengal in 1794. It was introduced on Java in 1835. Today cassava has spread to all tropical countries.

Use
The many varieties can be divided into two groups: sweet cassavas with little cyanic acid content; and bitter cassavas with a high cyanic acid content. This content ranges from 10-370 mg per kg of fresh tuber. In the bitter cassavas the cyanic acid has to be destroyed by washing and cooking.

The edible root tubers (M. esculenta 4), (M. esculenta 5), (M. esculenta 6) are an important food in many tropical countries. The peeled roots may be boiled or roasted. In West Africa a thick paste, fufu, is made by pounding boiled roots in a mortar. The great value of the crop is that it can be kept in the ground until needed (M. esculenta 7). The disadvantage is that it consists entirely of starch, resulting in malnutrition if not consumed with other nutrients.

Starch (M. esculenta 8) is prepared by grinding peeled tubers and washing out the starch. It is used for food, but also for the manufacture of adhesives, in sizing textile and laundry and for paper-making.

Cassava flour is made by grinding sun-dried slices of cassava tubers.

Tapioca, a name also applied to the plant in Asia, is made by heating clean starch on hot iron plates, causing agglutination into small round pellets. It is used for confectionery and in puddings.
The leaves (M. esculenta 9) are sometimes used as a boiled vegetable.

It is estimated that world acreage is about 8 million hectares, more than half of which is grown in Africa.