Vigna subterranean or Bambara nuts, Bambara groundnut, Congo goober, Earth pea, Baffin pea, Madagascar groundnut, Ground bean, Earth bean, Earth nut (English) or Juijiya, Gurjiya (Hausa) or Okpaotuanya or Okpa (Igbo) or Epiroro (Yoruba): An African important, but underutilized plant
Bambara nut is an African species, the cultivation of which predates that of groundnut. Although occasionally grown in Asia and elsewhere, its cultivation is rare outside the African continent. The distribution of wild Bambara groundnut is known to extend from Jos Plateau and Yola in Nigeria, to Garoua in Cameroon. It is in West Africa that most of the world’s Bambara groundnut is grown and where the crop is most prominent in the traditions of rural communities. Bambara groundnut grows close to the ground and the nuts are produced underground. It is therefore, a difficult crop to harvest mechanically which discourages large-scale commercialisation, but it is an ideal crop for smallholder households. Like peanut, Bambara bean develops slowly. Depending on climate and cultivar it may take anything from 90 to 180 days to mature. Most of today’s main types are ready to harvest in 130-150 days, or about 2 months after the pods first appeared. As a nitrogen-fixing legume, Gurjiya also contributes to the maintenance of soil fertility. Although normally grown in areas where cowpea and groundnut are grown, Bambara groundnut is considered to have an advantage over those crops in its adaptation to poor soils and tolerance to drought. Juijiya yields well under conditions which are too arid for groundnut, maize and even sorghum.
The crop yields reasonably well on poor soils in areas of low rainfall and can be grown without fertilisers and chemicals which are costly and often difficult to access in more remote areas. This plant can help alleviate poverty and sufferings of poor women. The bean is mostly produced by women, sold by women, and cooked and served by women. It therefore offers a convenient lever for lifting women up to a better existence. Improve this resource and you improve the lives of millions of mothers, not to mention babies born and unborn.
In a related vein, Bambara bean offers good opportunities for gender-oriented innovation and commercial development. In the Bida region in central Nigeria, for instance, women make pancakes (Kosai, Hausa) from the flour and reportedly enjoy a good living selling them.
Also in Mali women sell salted Bambara nuts, a premium product similar to macadamia nuts and suitable for urban areas and possibly for export as well. Gurjiya can be used for the prevention of food insecurity in Africa.
For much of Africa, unpredictable drought is the biggest fear and this crop might prove an ideal insulator against this periodic shock. Wherever rainfall is unreliable it tends to shine.
Bambaras, the people for whom the bean is named, live in parched, blisteringly hot districts along the Sahara’s southern fringe, and their namesake plant lives up to its etymological heritage. Bambara groundnut seeds can be eaten fresh, or cooked while still immature.
At maturity, they become very hard and, therefore, require boiling before further preparation. In many West African countries, the fresh pods are boiled with salt and pepper, and eaten as a snack. In Côte d’Ivoire, the seed is used to make flour, which makes it more digestible. In East Africa, the beans are roasted, pulverised and used to make a soup. The flour can also be used to make a stiff porridge.
Roasted seeds can be boiled, crushed and eaten as a relish. In Zimbabwe, the nuts are eaten fresh, and also dried and stored for later consumption. The fresh nuts may also be roasted and eaten as a snack. Bambara groundnut can be pounded and made into a relish mixed with onions, tomatoes and oil. The seeds may be milled into flour and used to make small flat cakes or biscuits or mixed with cereals and used to make a porridge.
The seeds are sometimes boiled and eaten together with plantains. In Zambia, it is also made into bread. In Zimbabwe, Bambara bean is canned. Another common practice is to crush the dried seeds into a paste. Various fried or steamed products made from this are very popular in Nigeria and neighbouring nations.
One, called Akara or Kosai or bean balls is a form of bean fritter that is frequently sold on the street and is especially common at bus stations. It is also prepared at home for breakfast, snacks, or side dishes at dinner. Another, called moi-moi, is a sort of savoury bean pudding. Yet a third, okpa, is a doughy paste that is wrapped in banana leaves and boiled.
These age-old favourite “fast-foods” are mainly made with other beans, but those made from Bambara are considered the best.
In the Ibo States of Nigeria, Bambara seeds are roasted and chewed with palm kernel as a snack item. Ripe or immature, the seed averages 63 percent carbohydrate, 19 percent protein, and 6.5 percent oil.
THE PROTEIN, AS FORMERLY NOTED, CONTAINS MORE OF THE NUTRITIONALLY ESSENTIAL AMINO ACID METHIONINE THAN THAT IN OTHER BEANS, MAKING IT MORE COMPLETE. Despite its high and balanced protein content, bambara remains underutilised, because it takes a long time to cook and has poor milling characteristics, since it does not dehull easily.
The long cooking time consumes more fuel and water than might be required for cowpea or common bean. Boiling from fresh Gurjiya may take 45-60 minutes, while dried beans may take as much as 3-4 hours. The seed has the reputation of being very filling. And no wonder: its nutritional energy (per 100g) has been measured at 367-414 calories, an amount greater than that of common pulses such as cowpea, lentil, and pigeon pea. Gurjiya is a good source of fibre, calcium, iron and potassium. The RED seeds could be useful in areas where iron deficiency is a problem, as they contain almost TWICE as much IRON as the cream seeds.
Often, it is the cream or white seeded Gurjiya which are more sought after and command up to a 10% premium in Ghana. Red seeds are more popular than the cream seeds in Zimbabwe, where they command a higher price with the Grain Marketing Board. Although formal infant-feeding studies are unreported, a trial has been conducted of “milks” prepared from Bambara bean, cowpea, pigeon pea, and soybean. Whereas all were declared acceptable, the scientists ranked Bambara-milk first in flavour, nutritional value, and colour.
The mothers and (seemingly) their babies preferred it too. Among beans this one is said to have the highest concentration of soluble fiber, a non-nutrient famously occurring in oat-bran and believed to reduce the incidence of heart disease and to help prevent colon cancer. In addition, the crop has medicinal uses in many areas in Africa.
In Botswana, for example, the black seeded landraces have the reputation of being a treatment for impotence. The medicinal role of Bambara nuts is mainly based on information obtained from communities in several parts of Africa, where this crop is reportedly responsible and useful for treatment of various ailments.
As a treatment for diarrhoea, a mixture of Gurjiya and water from boiled maize are consumed.
Raw Bambara nuts seeds are chewed and swallowed by pregnant women to alleviate the nausea associated with pregnancy.
The following uses of Gurjiya as traditional medicine have been noted by the authors:
Health benefits of Bambara nuts
(a) In several countries in sub-Saharan Africa, Bambara groundnuts play an important role in the diets of especially young rural children as it helps in overcoming the protein deficiency Kwashiorkor;
(b) The Igbos tribe in Nigeria use the seeds for treatment of venereal diseases;
(c) To treat polymenorrhea (frequent menstrual periods) it is recommended that Gurjiya seeds be roasted before consumption;
(d) The water in which Bambara seeds are boiled is used as treatment for internal bruising, and a mixture of water and crushed seeds are prescribed for treatment of cataracts;
(e) Gurjiya seeds have the highest concentration of soluble fibre as compared to other beans; this could contribute to the reduction of heart disease incidence and prevention of colon cancer;
(f) Surveys amongst local communities in northern Côte d’Ivoire revealed that the Bambara seeds are mainly used for medical treatments as opposed to other parts of the plant. The seeds are used to treat anaemia, ulcers (black Bambara variety mixed with an unidentified plant) and menorrhagia (heavy menstrual bleeding) during pregnancy (haemostatic drink prepared by a mixture of Bambara groundnuts flour and Pupalia lappacea (L.) Amaranthaceae (Ɗanka dafi, Hausa) dissolved in water).
The traditional uses of Bambara nuts to treat several ailments are noteworthy, and present a gap for detailed study on the pharmaceutical value of the crop.
This would provide yet another means of highlighting the potential of Gurjiya as an underutilised legume and tap into ways of encouraging more sustained production and use of Bambara groundnuts.
These are the thoughts of:
Sa’eed Halilu Bawa
Senior Lecturer (Associate Professor) at University of the West Indies, St. Augustine Campus, Trinidad.
Studied Food and Nutrition Sciences, Dietetics at Kaduna Polytechnic, Nigeria; Warsaw University of Life Sciences, Poland.