*3.1.3 Okpeye*

*Okpeye*, much like *dawadawa* is a traditional seasoning produced by solid substrate alkaline fermentation of *Prosopis africana* (African mesquite) seeds. *P. africana* grows across the African Savannah and rain forest regions, but is mostly used as source of seasoning in the middle belt and parts of the Southeastern Nigeria [3]. Like *dawadawa*, the household technology used for producing *okpeye* can also vary between cultures. Perhaps, the most common procedure for preparation of *okpeye*, as practiced in parts of Southeastern Nigeria is as described (**Figure 4)** [9]. The process involves boiling of the mesquite seeds for 12–24 h to cook the seeds, soften the seed coat and ease the de-hulling process. This is followed by de-hulling in a very laborious manual process. The cotyledons are washed thoroughly, drained and reheated (dry heat) in a pot lined with the leaves of *Alchornea cordifolia* popularly known as (*akwukwo okpeye*) by the native people. Other leaves such as banana leaves may be used when the conventional leaves are unavailable. The cotyledons are spread to a few cm depth in a shallow raffia basket already lined with leaves of *Alchornea cordifolia*, covered with more leaves and weighted with pebbles. This solid substrate fermentation arrangement is then placed outside under the sun in the day time and inside the house in the night (avoiding precipitation and moisture for the duration of the process). Fermentation proceeds for 4 days at uncontrolled temperature which varies from less than 30°C at night to over 37°C in the afternoons during very sunny days. At the end of this stage the fermented cotyledons now dark brown in color with strong ammonia-like smell are ground into a smooth paste and molded into different shapes and sizes. At this moment the product may be used but for more desirable quality, it is usually sun dried for a variable length of time at the end of which the product becomes hard and black with a more mellow and preferable aroma. The dried condiment is resistant to spoilage by microorganisms and has a very long shelf life with occasional re-drying under the sun [3]. **Figure 5** shows the stages in the traditional process of *okpeye* production. During the natural process the pH increases from an initial of 6.0–6.2 in the boiled unfermented substrate to 8.0–8.8 (sometimes pH of 9.0–9.2 may be achieved) in the fermented product [49]. In our laboratory a diversity of microorganisms were established to be involved in

#### **Figure 4.**

the primary fermentation. However, only species and strains of *Bacillus* were shown to be principal drivers of the process. Their populations increased significantly and persisted until the end. The organisms include *B. subtilis, B. velezensis*, and *B. amyloliquefaciens*. Other *Bacillus* species isolated include *B. licheniformis, B. anthracis, B. thuringiensis* and *B. cereus*. Apart from *Bacillus* species other bacteria that also participated in the fermentation especially at the early stages include *Enterobacter* sp., *Proteus mirabilis, Pseudomonas* sp., *Micrococcus* sp. and *Staphylococcus* sp. [49]. As in similar processes, these organisms are transient, incapable of producing condiments in pure culture and their roles in the process remain unclear.

## *3.1.4 Ugba*

*Ugba* is a Nigerian-based condiment prepared by the solid state alkaline fermentation of seeds of the African oil bean (*Pentaclathra macrophylla)*. It is also known

**25**

**Figure 5.**

*Current Status of Alkaline Fermented Foods and Seasoning Agents of Africa*

as *ukpaka* by the Igbos in the Southeastern part of Nigeria where it is most popular. *Ugba* is consumed as a delicacy, appetizer or used as a flavoring agent in various traditional dishes. Prepared in different ways, *ugba* is an important food product for various traditional ceremonies [9]. The production, like other traditional processes, is still carried out in various homes on small scale under uncontrolled condition

*Steps in the traditional fermentation of* P. africana *seeds to produce* okpeye*. (A) Seeds before boiling; (B) boiled seeds; (C) de-hulled seeds before fermentation; (D) de-hulled cotyledons spread on leaf lined basket; (E) fermentation taking place outside under the sun; (F) fermented cotyledons; (G) ground paste; (H) molded* 

The basic procedures (**Figure 6)** involve boiling of oil bean seeds for 12 h or more, removing the seed coat and slicing the cotyledons into thin slices. The slices are then soaked in water overnight, washed thoroughly and wrapped with fresh leaves for fermentation to take place. Fermentation is usually done at ambient temperature and the duration varies depending on the intended use. Fermentation can last as short as 3 days or up to 5 days. **Figure 7** shows African oil bean seeds, fermented slices of oil

Microbiological and biochemical changes that take place during the traditional process have been studied extensively [50, 51]. A diverse group of microorganisms were reported to participate in the traditional fermentation of African oil bean, with *Bacillus cereus* dominating the process [50]. Over 30 different organic compounds of varying molecular weights and volatility including alcohols, organic acids, ketone, aldehydes, hydrocarbons amines and esters have been shown to contribute to the flavor of the final product [51]. The specific contributions of these various molecules

bean cotyledons and fermented product (*ugba*) packaged in different ways.

remain to be established as also their flavor threshold in the product.

resulting in products that are non-uniform in quality.

*seasoning undergoing drying under the sun; (I) dried* okpeye *seasoning. Source: [89].*

*DOI: http://dx.doi.org/10.5772/intechopen.87052*

*Current Status of Alkaline Fermented Foods and Seasoning Agents of Africa DOI: http://dx.doi.org/10.5772/intechopen.87052*

#### **Figure 5.**

*New Advances on Fermentation Processes*

the primary fermentation. However, only species and strains of *Bacillus* were shown to be principal drivers of the process. Their populations increased significantly and persisted until the end. The organisms include *B. subtilis, B. velezensis*, and *B. amyloliquefaciens*. Other *Bacillus* species isolated include *B. licheniformis, B. anthracis, B. thuringiensis* and *B. cereus*. Apart from *Bacillus* species other bacteria that also participated in the fermentation especially at the early stages include *Enterobacter* sp., *Proteus mirabilis, Pseudomonas* sp., *Micrococcus* sp. and *Staphylococcus* sp. [49]. As in similar processes, these organisms are transient, incapable of producing condiments in pure culture and their roles in the process remain unclear.

*Ugba* is a Nigerian-based condiment prepared by the solid state alkaline fermentation of seeds of the African oil bean (*Pentaclathra macrophylla)*. It is also known

**24**

*3.1.4 Ugba*

**Figure 4.**

*Traditional process for the production of okpeye.*

*Steps in the traditional fermentation of* P. africana *seeds to produce* okpeye*. (A) Seeds before boiling; (B) boiled seeds; (C) de-hulled seeds before fermentation; (D) de-hulled cotyledons spread on leaf lined basket; (E) fermentation taking place outside under the sun; (F) fermented cotyledons; (G) ground paste; (H) molded seasoning undergoing drying under the sun; (I) dried* okpeye *seasoning. Source: [89].*

as *ukpaka* by the Igbos in the Southeastern part of Nigeria where it is most popular. *Ugba* is consumed as a delicacy, appetizer or used as a flavoring agent in various traditional dishes. Prepared in different ways, *ugba* is an important food product for various traditional ceremonies [9]. The production, like other traditional processes, is still carried out in various homes on small scale under uncontrolled condition resulting in products that are non-uniform in quality.

The basic procedures (**Figure 6)** involve boiling of oil bean seeds for 12 h or more, removing the seed coat and slicing the cotyledons into thin slices. The slices are then soaked in water overnight, washed thoroughly and wrapped with fresh leaves for fermentation to take place. Fermentation is usually done at ambient temperature and the duration varies depending on the intended use. Fermentation can last as short as 3 days or up to 5 days. **Figure 7** shows African oil bean seeds, fermented slices of oil bean cotyledons and fermented product (*ugba*) packaged in different ways.

Microbiological and biochemical changes that take place during the traditional process have been studied extensively [50, 51]. A diverse group of microorganisms were reported to participate in the traditional fermentation of African oil bean, with *Bacillus cereus* dominating the process [50]. Over 30 different organic compounds of varying molecular weights and volatility including alcohols, organic acids, ketone, aldehydes, hydrocarbons amines and esters have been shown to contribute to the flavor of the final product [51]. The specific contributions of these various molecules remain to be established as also their flavor threshold in the product.

**Figure 6.** *Flow chart for the traditional production of ugba.*

**Figure 7.**

*African oil bean seeds (A), fermented slices of oil bean cotyledons (B) and fermented oil seeds cotyledons (ugba) packaged in polythene bags or wrapped with local leaves.*
