Processing oil bean seeds involves several key steps to transform the raw seeds into a popular fermented food product known as Ugba or Ukpaka. This traditional method ensures the seeds are safe to eat and develops their unique flavour and texture through fermentation.
The process of converting oil bean seeds into Ugba follows a specific sequence of actions.
Key Processing Steps for Oil Bean Seeds (Ugba)
Based on traditional methods, the processing of oil bean seeds involves a series of physical and biological treatments. The main steps are:
- Boiling or Roasting: The process begins with cooking the raw oil bean seeds. This can be achieved by either boiling or roasting them.
- Dehulling: After cooking, the outer covering or husk of the seeds is removed.
- Shredding / Slicing: The cooked and dehulled seeds are then cut into smaller pieces, typically by shredding or slicing. This increases the surface area, which is important for subsequent steps like soaking and fermentation.
- Soaking: The shredded or sliced seeds are soaked. This step helps in washing and potentially reducing anti-nutritional factors.
- Washing: Thorough washing is carried out, often multiple times, to further clean the seeds and remove any residual undesirable compounds.
- Packaging: The prepared seeds are packaged, typically wrapped tightly in leaves (like banana or plantain leaves) or sometimes in plastic bags. This creates an anaerobic or semi-anaerobic environment necessary for fermentation.
- Fermenting: The packaged seeds are left to ferment for a specific period, usually a few days, at ambient temperature. This fermentation is driven by naturally occurring microorganisms, which break down complex compounds in the seed, developing the characteristic aroma, flavour, and texture of Ugba.
This sequence of boiling or roasting, dehulling, shredding / slicing, soaking, washing, packaging, and fermenting (Table 5 in reference) is essential for producing Ugba from oil bean seeds.
