Orphan crops can bring food security to millions of people

Introducing the African Yam Bean, a highly nutritious traditional crop

07 Sep 2016

Smallholders and people living in rural areas in Africa grow a huge variety of edible plants other than rice, wheat or maize. These crops, including the African yam bean, have long been neglected although they represent an excellent alternative food supplement to most diets.

Grown in pockets of tropical Central, West and East Africa, the African yam bean (Sphenostylis stenocarpa) has great potential to contribute to overall food security and improve local diets. This crop is not to be confused with the other yam bean, the jicama, which comes from Latin America. The African yam bean is a traditional crop, high in proteins and starch, is highly adaptable to adverse environmental conditions and can fix nitrogen in the soil, which means it does not require a large amount of fertilizers. It is usually grown together with maize or cassava.

Where it originated  

The African yam bean is thought to have originated in Ethiopia. Both the wild and cultivated varieties occur in East Africa from Eritrea to as far south as Zimbabwe, throughout West Africa from Guinea to southern Nigeria, being especially common in the latter, and in Togo and the Ivory Coast.

The crop is an enduring part of the food system of the Igbo and Yoruba peoples of Nigeria and special meals of yam beans feature in the marriage ceremonies of people living in the state of Ekiti in the western part of the country. 

What you should know 

The African yam bean, cultivated mainly for home consumption, is planted for its seeds, which are high in protein and low in calories, and are often eaten after being dried and ground into flour or simply boiled and seasoned. The starch-rich, tuberous roots, similar to spindly sweet potatoes in shape are consumed either fresh, cut in strips in salads, or dried and ground into flour. The leaves can also be cooked and eaten much in the same way spinach is.

The crop seems to be little affected by altitude and flourishes at elevations ranging from sea level to 1 800 meters. It takes five to seven months to grow and produce mature seeds. The crop, a vine growing to between 1.5 and 3 m in height, is green in colour or pigmented red. The vines twine clockwise around the stakes or climb around other crops for support; indeed the African yam bean is often used as a living fence. Due to its attractive, large pink and purple flowers, the plant is also cultivated as an ornament.  

Special qualities

  • Typical of legumes, the African yam bean adds a natural nitrogen boost in the soil and reduces the need for fertilizers in areas where it is cultivated.
  • The crop is highly adaptable and capable of growing even on acid and highly leached sandy soils of humid lowland tropics.
  • The African yam bean is usually intercropped with maize or cassava and also used in crop rotations.
  • It is mainly used as food for people, but is also used to feed animals.
  • The excessively long cooking time (4-6h) among other factors, limit the food use of the beans. However, this issue can be overcome using traditional cooking techniques, such as soaking the seeds in water from 4 to 8 hours – a practice that will reduce both the cooking time and the anti-nutrients.

Nutritional value

  • African yam beans have the advantage of producing both beans (pulse or grain) and an edible tuber.
  • The small tuberous roots are white fleshed, spindly and long like sweet potatoes, but contain more protein than sweet potatoes, cassava or yams.
  • The dried beans are also rich in protein (18.9%), with a good amount of dietary fibre (16.7%) and 1.5% of fat.

Send us pictures on our Instagram account with the hash tag #traditionalcrops, #africanyambean and any facts you might know about this crop. If you know of any recipes, we would love to hear about them.



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