HOW TO FERMENT UGBA (OIL BEAN)
Ugba, a product of alkaline fermentation of oil bean seeds (Pentaclethra macrophylla) is very popular among the Ibos and other ethnic groups in southern Nigeria. The product serves both as a delicacy and a food flavoring agent.
As an important nutritional item, ugba is very rich in protein. It similarly plays an economic, social and cultural role among the Igbos in the eastern part of Nigeria. The production of ugba is usually pursued as a family business that has become an art that is handed over from one generation to another.
The processing of these large brown glossy seeds of the African oil bean to obtain ugba is usually by natural fermentation, a process that involves microbiological and biochemical changes, caused by hydrolysis and desirable changes.
This process is usually influenced by the raw materials and the processing method with variations observed from one production batch or producer to another
However, studies have shown that fermentation drastically reduces anti-nutritional factors in many fermented legumes-based foods. It is well known that these foods contain naturally occurring toxins and anti-nutritional compounds.
The removal of anti-nutrients from Nigerian fermented food is an important step in ensuring toxicological safety and quality
Oil bean seeds require careful processing and fermentation before they can be eaten. Enujiugha, (2000) showed that seeds must be boiled in water before removal of the seedcoat.
Ugba is known to be rich in proteins, carbohydrates and lipids. Minerals and vitamins are reported to be in small quantity in unfermented ugba. Kabuo et al., (2007) reported that ugba contains some flavor and aroma components like ethyl oleate and ethylphenol. This makes ugba a good flavouring and seasoning agent in soups and local dishes.
The production process of ugba been previously described as alkaline fermentation of the seeds of the African oil bean tree.
Although the production method varies from one community to the other and from one processor to another, a similar end-product, which usually comes with pungent ammonia-like smell, is commonly produced across South Eastern Nigeria.
There is variation in boiling time and the procedure that aided dehulling of the seeds. After dehualling, cotyledons are either sliced or cooked for 30 min or longer.
There is overnight boiling before soaking and slicing. In the fermentation process, varied methods are used.
In some fermentation process the cotyledons are mixed with salt (sodium chloride ca.1–2 w/w), put in a clean pot, covered and fermented for up to 5 days at room temperature, with or without salt.
Sometimes sliced cotyledons were washed and allowed to drain for ½-1 h, in a basket lined with banana leaves (Musa sapientum Linn.) and later wrapped (about 40–50 g of slices per wrap) using another leaf (Mallotus oppositifolius) and incubated for 72 h at room temperature.
The differences in the various processing methods described could be responsible for the variations in the products quality observed from one community to the other.
The fermented bean slices at the end of the fermentation process are kept near smoldering firewood to develop the characteristic ugba flavor and the product is consumed as native salad.
However, fermentation for a longer period of time (6–10 days) produces very soft ugba which is used as soup flavoring (Sanni et al., 2002). Irrespective of which method is employed in the processing, one major drawback observed is the drudgery involved in the slicing process.
The Processes involved in Oil bean (Ugba) production
African Oil Bean Seed (Unprocessed Ugba)
Boiling (6 hours)
Cooling, Washing and Slicing (4-5×0.1-0.2 cm)
Washing and Boiling (2 hours)
Washing and Soaking (12 hours/ overnight)
Washing and Draining (30 minutes)
Packaging in Banana (Musa sapietum) leaves
Fermentation (72 – 96 hours)
By Akubuo Chigaemezu