Some food scientists are encouraging greater research on the butterfruit tree, or safou, [Dacryodes edulis], an underutilized plant that grows in the savannahs and tropical rain forests of West and Central Africa. It is one of many indigenous crops described in a set of books published by the US National Research Council called Lost Crops of Africa.

Butterfruit, or safou ? also called bush mango ? has been compared to avocado. It's an oil-producing fruit with a large seed and plumpy texture. Despite its somewhat sour taste, it is quite popular in parts of West and Central Africa, including the DRC, Benin, Nigeria and Central African Republic.

In many places, including southeastern Nigeria, the fruit appears at the beginning of the rainy season, when there is often little food left over from the harvests.

Anthropologist Jane Guyer of Johns Hopkins University (in Baltimore, Maryland) learned about butterfruit when she lived in Cameroon: 

"It looks like an oval plum ? with a shiny beautiful color," Guyer explains. 

"The trees have dark green leaves, and the fruit is copious and hangs down. So, you have a wonderful visual impression. We really enjoyed the season when they came into fruition, and I ate them with great gusto. There are people who prepare it as a snack on a roadside grill [where they are roasted]."

Paul Noren is a missionary with the Evangelical Covenant Church in Central African Republic. He and partner Roy Danforth have been working in agricultural development for decades.

"The butterfruit [safou].," he says,"produces a lot of fruit, which you put in boiling water and let steep for a few minutes. The flesh is softened like butter; it has a perfume type of flavor [with a] nice buttery texture and quite a bit of oil [from the pulp], so it is high in nutrition and in energy."

Butterfruit, or safou, is high not only in protein, but also in other properties that contribute to good health. It is used to strengthen undernourished children and nursing mothers.

Pablo Eyzaguirre is a senior scientist with the group Biodiversity International in Rome. 

"It is high in iodine," he says. " People who live away from the sea and don't get iodized salt have a prevalence of goiters?so safou provides some of those badly needed nutrients. And it's also high in calcium. In these forest areas, you don't keep much cattle and dairy producing animals. So between the calcium and iodine, it's a pretty healthy fruit to eat between the hard and lean times."

Eyzaguirre says pharmaceutical companies are looking into the fruit, which can help control diarrhea in young children. He says it can also be used to decrease high sugar levels, which play a role in the development of diabetes.

"They are also finding hyperglycemic properties, lower sugar levels." explains. "In the tropics [especially in cities] there are high starch diets [including large amounts of cassava, breadfruit and yams. They are eaten to compensate for small amounts of protein and other cheap foods that increase blood sugar levels].

"There's an absence of traditional lifestyles of being quite active and getting diverse plants [as food sources], so you find that in urban areas, diabetes is now a major source of disease in sub-Saharan Africa. So having a traditional fruit like this with antiglycemic properties that [are] readily available could be useful in lowering the incidence of diabetes and high blood sugar."

Butterfruit has many otheruses. 

The oil, made up of unsaturated fatty acids, can be used for cooking or in salad dressings.

The fruit can also be used like a tomato or other vegetable and eaten with cassava, maize and plantain. Sometimes, the flesh is processed into dried chips.

On the farm, the wood of the butterfruit tree can be substituted for mahogany to make furniture. Its bark produces a resin that creates a hot fire.

The tree can be used for shade in coffee and oil palm groves and to prevent soil erosion or act as a fence on family farms.

International research organizations are looking to expand production with improved horticultural techniques. 

Efforts are underway to plant the butterfruit tree in orchards. Food scientists are urging researchers to improve harvesting and storage methods to help prevent rot, shrinkage and premature fruit drop.

Agriculturalist Pablo Eyzaguirre says researchers have yet to document the full potential of butterfruit. They're also looking at its potential as and export crop, and pharmaceutical companies are showing growing interest in its oil.