Fermented locust bean is a common condiment to traditional stews and sauces in West Africa. It is made from the seeds of a number of trees, like Ceratonia siliqua (Carob),Parkia biglobos, P. africana (in Sudan)
It is called Iru in Yoruba, dawa dawain Hausa, and ogiri okpe in Igbo. It is also known
as afintin in Benin, sumbala in Mali & Guinea, netetou in
Senegal, and nere in some parts of Burkina Faso.
A common feature among these fermented legume seeds is the utilization of bacilli as the predominant microorganisms in the fermentation process, which produce an alkaline pH, contrary to most other fermentation processes. Because of the freed up ammonium that is released in the process, many of these products have an unpleasant smell.
The seeds are boiled to soften the hulls, which are then removed by pounding in a wooden mortar - sand is added to help loosen the hulls. Next the hulls are washed. There is a second boil after which the cotyledons are spread inside an ash lined calabash. The calabash is covered and wrapped to allow the beans to ferment. Fermentation takes 24 to 36 hours. Iru is rich in protein and lipids and contributes useful amounts of thiamine and riboflavin. In sun-dried form they can be stored for at least a year.
