This document discusses potential areas for improving traditional fermented food products in Nigeria. It suggests documenting traditional knowledge to prevent its loss, and developing a scientific understanding of microbial processes to refine production techniques. Areas for improvement include better understanding fermentation processes, controlling factors like starter cultures and conditions, and disseminating knowledge gains to support small-scale producers.

1. 1
BRIEF REVIEW ON IMPROVEMENT TECHNIQUES OF LOCALLY FERMENTED FOODS
ABSTRACT
Fermented foodstuffs and condiments are very popular in Nigeria. In many cases, fermentation is
responsible for the development of taste or aroma, improved digestibility, improvement of nutritional
composition, stabilization of the original raw materials and detoxification of anti-nutrient factors in
these products. Traditional fermented condiments (dawadawa, iru, ogiri) based on vegetable proteins,
and consumed by different ethnic groups in Nigeria have been the pride of culinary traditions for
centuries. It is evident that these products have played a major role in the food habits of communities in
the rural regions serving not only as a nutritious non-meat proteins substitute but also as condiments
and flavouring agents in soups. These condiments are being increasingly marketed throughout the
country and beyond in informal ways. Differences in the chemical composition of fermented
condiments are evident mainly because different ingredients have been used in their preparation.
Traditional methods of manufacture should take advantage of biotechnological progress to assure
reasonable quality and at the same time assure safety of these products. The requirements for a
sustainable biotechnological development of Nigerian condiments are discussed in the scope of the
microbiology and biochemical changes of the raw materials. Schemes to standardize the manufacturing
stages are proposed. Emphasis is placed on the relevance of the role of starter cultures in the traditional
methods of manufacture to ascertain appropriate nutritional quality and physical properties of the final
product. Fermented vegetable proteins have potential food uses as protein supplements and as
functional ingredients in fabricated foods. Relevant research and development activities are suggested.
Moreover, it is essential to increase the knowledge and understanding of the methods of preparation, in
order to improve the efficiency of fermentation, especially the traditional processes as the yields of
traditional fermentation processes are often low and sometimes the products are unsafe. This Work
discusses potential areas for improvement of indigenous fermented fruit and vegetable products.

2. 2
CHAPTER ONE
1.0 INTRODUCTION
Traditional diets in West Africa often lack variety and consist of large quantities of the staple food
(cassava, yam, maize) with supplements of plantain, cocoyam, rice, and beans depending on
availability and season (Achi, 1999). Soups eaten with the staples are an essential component of the
diet and may contain a variety of seeds, nuts, pulses, and leaves (Campbell-Platt, 1980).
The staple foods provide the calories but are poor in other nutrients. Soups are the main sources of
proteins and minerals and one of the ways to improve the diet have been to improve the nutrient
content of soups.
Seeds of legumes may account for up to 80% of dietary protein and may be the only source of protein
for some groups. Their cooked forms are eaten as meals and are commonly used in fermented form as
condiments to enhance the flavors of foods (Odunfa, 1985c; Aidoo, 1986; Achi, 1991; Oniofiok, 1996).
With high contents of protein, legume condiments can serve as a tasty complement to sauces and soups
and can substitute for fish or meat.
The food flavouring condiments are prepared by traditional methods of uncontrolled solid substrate
fermentation resulting in extensive hydrolysis of the protein and carbohydrate components (Fetuga et
al., 1973; Eka, 1980). Apart from increasing the shelf life, and a reduction in the anti-nutritional factors
(Odunfa, 1985b; Reddy and Pierson, 1999; Barimalaa et al., 1989; Achiand Okereka, 1999),
fermentation markedly improves the digestibility, nutritive value, and flavors of the raw seeds.
Although fermented food condiments have constituted a significant proportion of the diet of many
people, Nigerians have exhibited an ambivalent attitude in terms of consumer tastes and preferences for
such foods (Achi, 2005). The introduction of foreign high technology products especially processed
ones because of globalization and liberalization of the economy radically changed the Nigerian food
culture into a mixed grill of both foreign and local dishes (Ojo, 1991).
Many developing countries are still preparing traditional fermented products for human consumption
(Campbell Platt, 1987). Fermented products remain of interest since they do not require refrigeration
during distribution and storage. The traditional condiments have not attained commercial status due to
the very short shelf life, objectionable packaging materials, stickiness and the characteristic putrid
odour (Arogba et al., 1995). Fermented condiments often have a stigma attached to them; they are
often considered as food for the poor. The production of fermented vegetable proteins for use as food
condiments is craft-based. Remarkably, in many areas of Nigeria today they are still made in traditional
ways, with success depending upon observance of good manufacturing practices and control of

3. 3
environmental conditions during the manufacturing phase. Starter cultures are not normally used and
therefore variations in the quality and stability of the products are often observed.
As with any other fermentation process the understanding of the microbial ecology of vegetable
fermentations requires the knowledge of the fermentation substrates, i.e. the seeds of the various plants
as well as the products obtained thereof. Information on the manufacturing and microbiology of
indigenous fermented legumes has been reported (Odunfa, 1981a, 1983a; 1985a, 1985c; Odunfa and
Adewuyi, 1988a,b; Achi, 1992; Sanni, 1993; Sanni and Ogbonna, 1998). The use of these condiments,
it is suggested, could be extended as a food ingredient included into most fabricated foods in order to
further increase their versatility and utility (Giami and Bekebain, 1992; Achi, 1999). Fermented fluted
pumpkin flour has been incorporated into weaning food formulations (Achinewhu, 1987; Banigo and
Akpapunam, 1987).
Apart from dawadawa prepared from the African locust bean, by far the bulk of the indigenous
fermented condiments of Nigeria are to be found in the southern states of Nigeria. The north is very
poor in food fermentations, which are practically confined to the staple sorghum porridges and to
soured milks (Dirar, 1993). However, inter state trade and relocation has widened the scope of the
spread of food condiments throughout the country and beyond (Iwuoha and Eke, 1996).
Excellent reviews of traditional fermented foods have been published by Odunfa (1985c), and Iwuoha
and Eke (1996). Against the background of the significance and benefits of traditional fermented

4. 4
condiments, the object of this review was to evaluate the current state of knowledge of fermented food
condiments dealing with aspects of manufacture, biochemical changes, and nutritional properties. Use
of other raw materials other than the traditional legumes for condiment-making will be included.
Traditional diets in West Africa often lack variety and consist of large quantities of the staple food
(cassava, yam, maize) with supplements of plantain, cocoyam, rice,and beans depending on availability
and season (Achi, 1999). Soups eaten with the staples are an essential component of the diet and may
contain a variety of
seeds, nuts, pulses, and leaves (Campbell-Platt, 1980).
The staple foods provide the calories but are poor in other nutrients. Soups are the main sources
of proteins and minerals and one of the ways to improve the diet have been to improve the nutrient
content of soups. Seeds of legumes may account for up to 80% of dietary protein and may be the only
source of protein for some groups. Their cooked forms are eaten as meals and are commonly used in
fermented form as condiments to enhance the flavors of foods (Odunfa, 1985c; Aidoo, 1986; Achi,
1991; Oniofiok, 1996). With high contents of protein, legume condiments can serve as a tasty
complement to sauces and soups and can substitute for fish or meat. The food flavouring condiments
are prepared by traditional methods of uncontrolled solid substrate fermentation resulting in extensive
hydrolysis of the protein and carbohydrate components (Fetuga et al., 1973; Eka, 1980). Apart from
increasing the shelf life, and a reduction in the anti-nutritional factors (Odunfa, 1985b; Reddy and
Pierson, 1999; Barimalaa et al., 1989; Achi and Okereka, 1999), fermentation markedly improves the
digestibility, nutritive value, and flavors of the raw seeds.

5. 5
CHAPTER TWO
2.0 A BRIEF REVIEW OF POSSIBLE IMPROVEMENT TECHNOLOGY IN TRADITIONAL
FERMENTATION PROCESS
Fermentation is one of the oldest forms of food preservation technology in the world. Indigenous
fermented foods such as bread, cheese and wine, have been prepared and consumed for thousands of
years and are strongly linked to culture and tradition, especially in rural households and village
communities. Fermented foods are popular throughout the world and in some regions make a
significant contribution to the diet of millions of individuals. For instance Soy sauce is consumed
throughout the world and is a fundamental ingredient in diets from Indonesia to Japan. Over one billion
litres of soy sauce are produced each year in Japan alone. In Africa fermented cassava products (like
gari and fufu) are a major component of the diet of more than 800 million people and in some areas
these products constitute over 50% of the diet. Fermentation is a relatively efficient, low energy
preservation process, which increases the shelf life and decreases the need for refrigeration or other
forms of food preservation technology. It is therefore a highly appropriate technique for use in
developing countries and remote areas where access to sophisticated equipment is limited. There is
tremendous scope and potential for the use of micro-organisms towards meeting the growing world
demand for food, through efficient utilisation of available natural food and feed stocks and the
transformation of waste materials.
There is a danger that the introduction of 'western foods' with their glamorous image will displace these
traditional fermented foods. Although fermentation of foods has been in use for thousands of years for
the preservation and improvement of a range of foods, the microbial and enzymatic processes
responsible for the transformations were, and still are, largely unknown. Because of the tremendously
important role indigenous fermented fruits and vegetables play in food preservation and their potential
to contribute to the growing food needs of the world, it is essential that the knowledge of their
production is not lost. Moreover, it is essential to increase the knowledge and understanding of the
methods of preparation, in order to improve the efficiency of fermentation, especially the traditional
processes as the yields of traditional fermentation processes are often low and sometimes the products
are unsafe. This Work discusses potential areas for improvement of indigenous fermented fruit and
vegetable products. It can be divided into four main areas:
 Improve the understanding of the fermented products
 Refine the processes
 Disseminate the improvements
 Create a supportive policy environment.
2.1 Improving the understanding of fermented products
For fermented products such as cheese, bread, beer and wine, which are produced on a commercial
scale, a good understanding of the microbial processes has been developed. However with many of the
fermented products in Africa, Asia and Latin America, knowledge of the processes involved is poor. It
is likely that the basic principles apply across the board, but production conditions vary enormously
from region to region, giving rise to numerous variations of the basic fermented product. It is not the
intention or the desire to standardise the process and thereby lose this huge diversity, rather it is to
harness the tremendous potential these methods have to contribute to increasing not only the quantity,
but quality of food available to the worlds population.

6. 6
There are two main reasons for gaining a better understanding of indigenous fermented products:
 Documenting the traditional knowledge to ensure that the huge diversity is not lost
 Developing a scientific understanding of the microbial processes, with a view to improving the
efficiency of the process
2.1.1 Documenting the traditional knowledge
Fermentation is one of the oldest food processing technologies in the world. The knowledge of how to
make these products has often been passed down from parent to child (usually mother to daughter) and
belongs to that undervalued body of "indigenous knowledge". Most of this knowledge has not been
documented and is in danger of being lost as technologies evolve and families move away from
traditional food preservation practices.
The collection and preservation of indigenous knowledge is of interest to governments, historians,
anthropologists and scientists, to name but a few. Several individuals and organisations are actively
involved in research in this area:
Several research institutes and scientists in Africa, Asia and Latin America are recording information
on traditional fermented foods. Dr Karki in Nepal and Hamid Dirar have been extensively quoted in
this book and their work on fermented products in Nepal and Sudan is of great importance.
Intermediate Technology has been collecting information about traditional food products from Africa,
Asia and Latin America. The first volume of products was published in 1997 (Fellows, 1997). This
included the following fermented food products: kenkey, ogi, injera, fermented sweet bread, sorghum
beer, palm wine, banana beer, pineapple peel vinegar, lime pickle, tamarind pickle, mango pickle, gari,
vegetable pickle, coconut toddy, yoghurt, ayib and dawdawa. Volume 2 will be published in 1999 and
regional publications on the traditional food products of Bangladesh, Southern Africa and the Andes
are planned.
The European Union has just completed an audit of the traditional food products of Europe. The results
have been published in a series of publications (Cowan, 1998).
The Special Programme on Biotechnology and Development Cooperation for the Netherlands
Government was established in 1992 to improve the access of developing countries to biotechnological
expertise and innovation with a focus on using biotechnology for the benefit of small-scale farmers and
producers. Part of the programme involved a competition to identify farmers' existing biotechnology
practises. This programme resulted in the collection of valuable information about traditional
fermented food products (Bunders et al, 1996).
Finally, the Food and Agriculture Organisation of the United Nations sees the value in collecting and
preserving this source of knowledge. This book is an example of their work.
2.1.2 Developing a scientific understanding of the microbial processes
Most traditional fermented products are made by natural fermentations carried out in a non-sterile
environment. The specific environmental conditions cause a gradual selection of micro-organisms
responsible for the desired final product. This is appropriate for small-scale production for home
consumption. However the method is difficult to control and there are risks of accompanying micro-
flora causing spoilage and unsafe products.

7. 7
If the processes are to be refined, with a view to production on a larger scale, it is essential to have a
scientific understanding of the fermentation processes. This can be developed by:
 The isolation and characterisation of the essential micro-organisms involved;
 The determination of the role of external factors in fermentations and the effects of these on the
metabolism of micro-organisms
 The investigation of the effects of pre-treatments of raw materials on the fermentation process
 The identification of the options for further processing and how these affect the taste and
texture of the product.
This research is capital intensive and usually requires scarce foreign exchange. It requires the use of
sophisticated equipment and reagents backed with a consistent energy and water supply which are not
always available in developing countries. To meet the current and future challenges in developing
countries, it is important that these countries develop the capabilities to benefit from improvements in
fermentation methodologies.
Biotechnologies need to be developed which are affordable by the poor, since it is they who are likely
to benefit most by improvements to the traditional processes.
2.2 Refining the process
The art of traditional processes needs to be refined to incorporate objective methods of process control
and to standardise quality of the final product without losing their desirable attributes such as improved
keeping quality, taste and nutritional qualities.
Science based fermentation research has often focused mainly on improving the metabolic properties
of the micro-organisms used as a starter culture, using the techniques of selection, mutation and genetic
modification. To achieve this a full understanding of the fermentation process is needed. The properties
of the starter culture must be known and culture conditions must be controllable. This means that
science based fermentation research currently has little to offer traditional food processing (Broerse
and Visser, 1996).
2.2.1 Process control
Once the details of the fermentation process and the microbes involved are known and understood, it is
possible to begin to refine and improve the process. The commercially produced products, such as
bread, wine, soy sauce and pickles are all examples of processes which have been studied and
optimised. Recently traditional fermented products in Africa have been industrialised. In Nigeria,
Dadwa (a fermented legume product) is now made by Cadburys and in Zimbabwe, traditional
fermented milk is made industrially and sold as "Lacto" (Okafor, 1992).
The areas where the efficiency and yield of food fermentation processes can be increased are:
 The selection or development of more productive microbial strains
 The control and manipulation of culture conditions
 The improvement of product purification and concentration.

8. 8
Techniques to control the fermentation processes could include the development of pure starter
cultures. Developing these by laboratory selection or genetic engineering is not viable. A more feasible
approach would be to exploit the ecological principle of inoculum enrichment by natural selection.
Another approach to stabilise fermentation under nonsterile conditions is the use of multi-strain
dehydrated starters which can be stored at ambient temperature. These are already used for the
manufacture of tempeh (Nout, 1992).
2.2.2 Quality control
The aim of quality control is to ensure that every batch of food produced has a satisfactory and uniform
quality. This does not necessarily mean that it is the highest quality possible but that it reaches the
standard the customers are willing to pay for (Fellows, 1996) .
Inadequate quality control can have an adverse effect on local demand for the product. This is
particularly a problem for small-scale traditional production. In modern industrial applications, the
fermentation equipment and processes are controlled using expensive technology, resulting in a
consistent product of a known quality. Traditional practises take place in a less predictable
environment. This can result in mistakes including sour beer and mouldy pickles.
It is often felt that traditional products made at the small scale are unhygienic and unsafe. This is
sometimes true. However the case is often overstated. Many fermented foods are inherently safe due to
low moisture contents or high acidity. Lime pickle from India and Gundruk from Nepal are good
examples. Several of the steps in traditional processing are designed to reduce contamination. These
include boiling, adding salt and sun drying.
Quality control procedures are essential for the production of safe products and contribute to the
success of small food processing businesses. Appropriate quality control procedures need to be
developed and implemented. These procedures need to be developed with the processors who must
understand and apply them. The quality of food is highly subjective. What is acceptable to one
customer is not acceptable to another. It is important to carry out participative research to identify ways
to improve the quality control procedures for fermented food products.
The sort of areas that should be investigated include:
 Selecting good quality raw materials
 Processing under correct conditions
 Ensuring high standards of personal hygiene by the food processors
 Ensuring the processing area is sufficiently clean
 Using correct packaging
2.3 Disseminating improvements
Documentation of the traditional methods of food fermentation and research to identify improved
methods of production are meaningless if the results are not disseminated to those who are likely to put
them into practice.

9. 9
There is a danger of mystifying the fermentation process by enrobing it in scientific theory. What was
once a simple process carried out by any family member, in the confines of the household, using
locally available equipment and materials, could become a process to be feared. It is important to be
realistic and to ensure that the improvements recommended are ones which can easily be put into
practice. The aim is not to deter the production of fermented foods at the small scale, but to encourage
their production and consumption on a larger scale.
Fermented foods often have a stigma attached to them – they are considered as poor mans food. As
soon as a family can afford to buy processed foods, they move away from carrying out home
fermentation. This is a pity, because as we have seen earlier, fermented food products have many
nutritional advantages which surpass western-style fast foods and processed foods. Where cultural
values attached to the fermented food are strong, it is unlikely that there will be an image problem. For
example, kimchi is considered part of the national heritage in Korea. It is a vital ingredient of all meals
and as such is a highly valued food. This is reflected in the amount of research carried out on the
product and the detailed understanding of the process, which already exists.
It is not difficult to gain access to village people, both to collect the traditional information and to
disseminate improved practices. Numerous organisations are involved in field projects. They can be
used to organise training sessions and group meetings for the dissemination of new methods, for
example, for the use of pure starter cultures.
One of the problems likely to be encountered is gaining access to starter cultures and other improved
methods. Agricultural extension services should take a responsibility for the promotion and the supply
of starter cultures at a price which is affordable.
2.4 Creating a supportive environment for production of fermented food products
Developing countries need to build their resources of trained, knowledgeable individuals, who are able
to apply the basic microbiological principles to the production of fermented foods. Extra support
should be made available to train professionals in this discipline.
Fermented foods should be recognised as part of each countries heritage and culture and efforts made
to preserve the methods of production. A recognised body (government or non-government) should
take the responsibility for the collection of details and the promotion of fermented food products.
Consumers need to be made aware of the numerous benefits of fermented foods and their prejudices
against fermented foods, especially those traditionally produced at the home scale, dispelled.
Many traditional fermented foods are produced from minor or wild fruits and vegetables, many of
which are being lost through deforestation and loss of biodiversity.
For the purpose of this literally research review, traditional fermentation of vegetable protein
condiments are considered.

10. 10
CHAPTER THREE
3.0 Traditional Fermented Protein Condiments in Nigeria
Traditional fermented condiments (dawadawa, iru, ogiri) based on vegetable proteins, and consumed
by different ethnic groups in Nigeria have been the pride of culinary traditions for centuries. It is
evident that these products have played a major role in the food habits of communities in the rural
regions serving not only as a nutritious non-meat proteins substitute but also as condiments and
flavouring agents in soups. These condiments are being increasingly marketed throughout the country
and beyond in informal ways. Differences in the chemical composition of fermented condiments are
evident mainly because different ingredients have been used in their preparation. Traditional methods
of manufacture should take advantage of biotechnological progress to assure reasonable quality and at
the same time assure safety of these products. The requirements for a sustainable biotechnological
development of Nigerian condiments are discussed in the scope of the microbiology and biochemical
changes of the raw materials. Schemes to standardize the manufacturing stages are proposed.
Emphasis is placed on the relevance of the role of starter cultures in the traditional methods of
manufacture to ascertain appropriate nutritional quality and physical properties of the final product.
Fermented vegetable proteins have potential food uses as protein supplements and as functional
ingredients in fabricated foods. Relevant research and development activities are suggested.
Key words: Traditional condiment fermentation, dawadawa, iru, ogiri, manufacturing process, starter
cultures.
3.1 Names and Substrates of Fermented Condiments
Throughout Nigeria, many names are applied to the multitude of fermented food condiments. Table 1
shows the variety of names by which the products are known in different parts of the country. The
exact origin of such names could be attributed to (a) the region or area of manufacture (b) the type of
legume or oil seed used and (c) the spelling according to region or area. The Yorubas of the
southwestern Nigeria locally call fermented condiments ‘iru’ while the Hausas who inhabit most of the
northern part of Nigeria call it dawadawa. Ogiri’ is the name used by the Ibos of the southeastern
Nigeria. Owoh on the other hand, is the popular name among the Urhobos and Itsekiris in the Niger
Delta region for foodcondiments. Similarly, okpiye is popular among the Igala and Idoma people of the
Middle Belt region.
The conventional substrates for condiment production are diverse and each can be produced
from more than one raw material. Almost any edible plant material can be subjected to fermentation.
Judging by the available literature, over nine different fermented products are condiments. A list of
these substrates is given in Table 1. For instance, dawadawa or iru is traditionally prepared from
African locust bean (Parkia biglobosa) (Campbell- Platt, 1980; Odunfa, 1981a; Antai and Ibrahim,
1986), soybean (Glycine max) (Popoola and Akueshi, 1984; Ogbadu and Okagbue, 1988) and bambara
groundnut (Vigna subterranea)(Barimalaa et al., 1994).

11. 11
Ogiri is traditionally prepared by fermenting melon seeds (Citrullus vulgaris) (Odunfa, 1981b;
Ogundana, 1980), fluted pumpkin (Telferia occidentale) (Odibo and Umeh, 1989) or castor oil seed
(Ricinus communis) (Anosike and Egwuatu, 1981; Odunfa 1985b; Barber et al., 1988).
Owoh is processed from fermented seeds of the cotton plant (Gossypium hirsutum) (Sanni and
Ogbonna, 1991; Sanni and Ogbonna, 1992) and African yam bean (Sphenostylis stenocarpa) (Sanni et
al., 2001), while Okpiye is prepared from the seeds of Prosopis africana (Achi, 1992: Odibo et al.,
1992; Sanni, 1993). Quite often seeds that are used for fermentation are inedible in their
raw unfermented or cooked state.
3.2 Basics ofManufacturing Processes
The methods employed in the manufacture of fermented condiments differ from one region to another
because these processes are based on traditional systems, some of which are summarized in Table 2. A
basic scheme of vegetable fermentation for production of condiments is depicted in Figure 1.
According to local custom, climate conditions and the type of substrates used, specific process
variations occur. In general, fermentation takes place under conditions which the producers have found
to be favorable for the appropriate growth and activity of the microorganisms.
Traditionally, raw beans are cooked for upward of 12 hours in excess water until they are very soft to
allow for hand de-hulling. The length of time of cooking depends on the strength of the testa and on the
de-hulling efficiency of the seeds. Parkia biglobosa can be cooked for 8-12 h (Oyewole and Odunfa,
1990), though Prosopis africana can be cooked for 5-6 h (Achi, 1992). Boiling in 0.1 M Na2CO3
reduces the cooking time to 4 h and increases the de-hulling efficiency to 89% (Achi and Okereka,
1999). While Telferia seeds require minor cooking for 30 to 60 min, Citrullus vulgaris and castor seeds
are deshelled before cooking.

12. 12
At present, most de-hulling processes rely on the tedious method of hand separation. Abrasive de-
hulling of dry beans of Parkia or Prosopis is not possible because of the strong adherence of hulls to
the seed. Nevertheless, roasting prior to boiling in water has been identified as a technique for effecting
reduction in cooking time (Ijabo et al., 2000). Boiling in excess water serves not only the purpose of
partial cooking, but facilitates microbial penetration and human digestion. The bitter and beany taste of
soybean disappears in less than 15 min at 95°C (Nout et al., 1985).
After cooking and de-hulling processes have been completed, the cotyledons are prepared for
fermentation. For some seeds, such as the African oil bean (Pentaclethra macrophylla), the cotyledon
may be boiled again for 1-2 h. A softening agent ‘kaun’ (potassium carbonate) may be added to aid
softening of the cotyledons (Odunfa, 1985c; Ikenebomeh et al., 1986). Ugba is produced from the
sliced seeds of Pentaclethra macrophylla. These slices are mixed well with salt and wrapped in banana
leaves. A three-day fermentation provides the delicacy, while 5 days of fermentation produces the soup
condiment (Odunfa and Oyeyiola, 1985). Other substrates are pounded into a batter before wrapping in
banana leaves or other suitable leaves. Incubation takes 72-96 h at 28-42°C. The process involves
moist solid substrate fermentation by spontaneous natural inoculation. This is unlike most other
Nigerian fermented foods, which take place in a liquid environment. The imperative incubation
condition could be described as that of oxygen starvation, allowing microbial growth. In practice this is
achieved by wrapping with suitable leaves so that the package can be opened for aeration and cooling
if necessary.

13. 13
Insufficient packaging density with consequent pockets of air, non slicing of African oil bean,
including packaging in polyethylene bags and other factors may result in fermentation failure as
reported by Ogbonna et al. (2001).
The consistency of the fermenting vegetable mash as fermentation progressed could be
described as a thick cheesy pudding. After fermentation for 72-96 h, the mash become soft and dark
and has a characteristic strong ammoniacal odour resembling Japanese natto (Odunfa, 1985c, 1986;
Achi, 1992; Barimalaa et al., 1994).
Fermented condiments do not keep well if the fermentation is allowed to continue long
uninhibited. If fermentation is prolonged, the environment will be changed to become suitable for yeast
growth (Campbell- Platt, 1987). Furthermore, over-fermentation is capable of generating unacceptable
levels of volatile fatty acids.
3.3 MICROBIAL ECOLOGY
The dynamics of fermentation in any food matrix is a complex microbiological process involving
interactions between quite different microorganisms (Daeschel, 1987). The contribution of the
accompanying flora of fermenting substrates is determined by the substrate composition and hygiene
during production. During fermentation, the microorganisms use the nutritional components of the
seeds, converting them into products that contribute to the chemical composition and taste of the
condiment. Quite a number of Bacillus species have been isolated from various fermented food
condiments (Table 3). Although yeasts and other bacteria are also seen, only part of them can be
considered to play a substantial role in fermentation processes. For example, non-fermenting species
may just be ubiquitous contaminants although they may affect the flavour of the final product when
occurring in high numbers. Other bacteria present include Staphylococcus spp. Proteolytic and salt-
tolerant microorganisms have been detected in appreciable numbers (from 104 to 10 6 cfu/g) in
samples of fermenting Parkia seeds after 36 h (Odunfa, 1981a).

14. 14
The spore-forming species B. subtilis and B. lichenformis were identified as the main bacteria present.
The predominance of Bacillus species has been demonstrated in other fermenting legume proteins
(Achi, 1992; Barimalaa et al., 1994; Barber et al., 1998; Omafuvbe et al., 2002). The codominance of
Staphylococcus and Bacillus spp. was typical of the microflora of fermenting beans (Obeta, 1983;
Antai and Ibrahim, 1986; Achi, 1992). Staphylococcus species have been associated with fermenting
foods of plant origin especially vegetable proteins (Odunfa and Komolafe, 1989; Jideani and Okeke,
1991). Fresh fruits and vegetable often carry high levels of these organisms as part of their normal
flora. Members of the Enterobacteriacceae also contributed to the ecology of fermenting plant proteins
especially at the early stages (Mulyowidarso et al., 1989; Achi, 1992). These species do not survive
until the end of the fermentation, presumably because of the modified environment, which had
developed at later stages.
In view of the fact that the major constituents of vegetable seeds are proteins, the organisms
responsible for fermenting them must be capable of utilizing these constituents (Antai and Ibrahim,
1986; Ouoba et al., 2003a). Bacillus species isolated from variable sources have been reported to be
proteolytic and are able to breakdown oils (Frazier, 1967; Forgarty and Griffin, 1973; Ouoba et al.,
2003b). It is evident that production of fermented condiments is initially mediated by a diverse
microbial flora, which eventually becomes Gram-positive flora (a reflection of many African
fermented foods) (Odunfa, 1985c). The contribution of this accompanying flora of bacteria to the
properties of the legume product is only partly understood (Iwuoha and Eke, 1996). Most probably,
they play a role in flavour development and influence the chemical composition through substrate
modification and synthesis of vitamins (Nout and Rombouts, 1995). However it is necessary to
ascertain the contribution of these organisms in vegetable fermentations. Undoubtedly, traditionally
fermented condiments have not been incriminated in relation to food poisoning.
3.4 STARTER DEVELOPMENT
The fermentation process for condiment production is still being carried out by the traditional village-
art method.
There is need to apply modern biotechnological techniques like the use of starter cultures in improving
traditional food processing technologies (Achi, 2005). It has been suggested that even though hitherto
most fermentation processes used in developing countries do not use innocula or extrinsic cultures,
these processes could be improved by using starter cultures, and also by backslopping, which entails
application of brine from prior fermentation cycles (Holzapfel, 2002; Naiba, 2003).
Starter cultures have been found to reduce fermentation time as well as guarantee product
quality. In the traditional method of manufacture, the fermentation of the legume seeds is achieved by
indigenous microflora or the addition of fermented material from a previous production through back
slopping. Thus, it may be assumed that undefined starter cultures have traditionally been
employed in the manufacture of these products. (Suberu and Akinyanju, 1996; Omafuvbe et al., 2002;
Ouoba et al., 2003 a,b; Dakwa et al., 2005). A pure culture starter is essential for controlled
experimental fermentations, and for this purpose a number of Bacillus species, Staphylococcus and
Streptococcus enterococcus have been explored (Suberu and Akinyanju, 1996; Omafuvbe et al., 2003;
Ouoba et al., 2003a,b). Controlled fermentation of soybeans was achieved by using pure single cultures
of Bacillus subtilis, B. licheniformis or in combinations (Suberu and Akinyanju, 1996; Sarkar et al.,
1993). Mixed cultures of B. subtilis and B. licheniformis were highly recommended by the same
authors and fermentation was achieved in 72 h. Omafuvbe et al. (2003) on the other hand, tested three
Bacillus species namely B. subtilis, B. licheniformis and B. pumilis singly and in combinations for their
ability to ferment soybean for the production of daddawa. B. subtilis as single or member of a mixed
starter produced soy-daddawa, which was considered most suitable as it gave acceptable pure culture
condiment supposedly due to its proteolytic enzyme activity and high level of free amino acid.
Most authors now agree that there is a predominant development of Bacillus species during the various
legume fermentation processes (Aderibigbe and Odunfa, 1990; Odunfa and Oyewole, 1986; Achi,

15. 15
1992; Odibo et al., 1992; Ouoba et al., 2003a). The use of a single strain would seem too restrictive for
the production of a foodstuff with a generous range of organoleptic characteristics. The use of a
mixture of microorganisms with complementary physiological and metabolic properties seems to be
the best approach for obtaining a product with the nutritional and sensory properties desired.
Understanding of the phenomena of succession of the different populations involved in these natural
processes is therefore required. The significant point in the comprehension of the mechanism of
effecting degradation of legume proteins lies in the analysis of the amino acids produced by the
isolated bacteria. The study of the starters contributing to the production of amino acids is still meager
(Ouoba et al., 2003a) compared to the research works conducted on other aspects fermentation.
3.5 BIOCHEMICAL CHANGES ACCOMPANYING FERMENTATION
Since the major constituents of legumes and oilseeds used in condiment production are proteins, fats
and fewer carbohydrates, the organisms responsible for the hydrolysis must be capable of utilizing
these constituents.
3.5.1 Changes in carbohydrates
Bacillus species have been reported as producers of certain enzymes such as amylase, galactanase,
1618 Afr. J. Biotechnol. galactosidase, glucosidase and fructofuranosidase, which are involved in the
degradation of carbohydrates (Aderibigbe and Odunfa, 1990; Sarkar et al., 1997b;
Omafuvbe et al., 2000; Kiers et al., 2000). Microbial amylases hydrolyze carbohydrates into sugars,
which are then readily digestible by humans. Similarly, galactanases soften the texture of the seeds and
liberate sugars for digestion. Most legumes contain large amounts of non-digestible carbohydrates,
which may include arabinogalactan, stachyose, sucrose and raffinose (Irvine, 1961; Odunfa, 1983).
Soybean may contain in addition, verbascose. These carbohydrates are associated with abdominal
distention and flatulence in humans (Sarkar et al., 1997b; Naczk et al., 1997). Fermentation reduced
total flatus factors from 16.5 to 2.0 mg/g in soybeans (Winarno and Reddy, 1986), and from 0.16% to
<0.1% in groundnut (Fardiaz and Markakis, 1981). Trypsin inhibitor activity of Bambara groundnut
(Barimalaa et al., 1994) was also reduced during fermentation.
3.5.2 Changes in amino acids
In most fermented high-protein products, the extent of protein hydrolysis is one of the most important
factors in the changes in texture and flavour (Whitaker, 1978). Soluble low molecular weight peptides
and amino acids that contribute to flavour are produced through the enzymatic breakdown of proteins
(Odunfa, 1985c; Njoku and Okemadu 1989; Ogbonna et al., 2001; Ouboa et al., 2003a). Condiment of
good quality has a characteristic strong smell of ammonia, a dark colour and is semi hard.
Amino acids produced because of protein metabolism are responsible for the gradual pH
increase and leveling off towards 7.5-8.0 (Barimalaa et al., 1989; Achi, 1992; Barber and Achinewhu,
1992; Sarker et al., 1997a) (Table 3). The increase in pH into the alkaline range may be physiologically
important for tolerance and adaptation of fermenting microorganisms in the environment. However, pH
increases due to the formation of ammonia from amino acids may consequently encourage growth of
spoilage organisms such as lactobacilli and pediococci. The effect of vegetable protein fermentation on
total nitrogen is negligible. However, slight increases may be observed in some legume seeds (Winarno
and Reddy, 1986; Achinewhu et al., 1992). Free amino acids increase but longer fermentation results in
losses of lysine or other essential amino acids (Winarno and Reddy, 1986).
3.5.3 Changes in lipids
The significant lipolysis of legumes yields predominantly oleic, linoleic and linolenic acids
(Achinewhu, 1987b; Ouoba et al., 2003b; Nout and Rombouts, 1990). Free fatty acids, particularly
oleic, linoleic and linolenic acids were associated with non-specific antitryptic activity

16. 16
(Winarno and Reddy, 1986). As such, extensive hydrolysis could diminish nutritional quality.
Although oils constitute up to 40% of the legumes used in food fermentations, extensive lipolysis does
not take place. Odunfa (1985c) reported low levels of lipase activity in Parkia biglobosa during
dawadawa production. The same author had earlier reported low levels of lipase in melon seed
fermentation (Odunfa, 1983b). Similarly, Njoku and Okemadu (1989) observed minimal participation
of lipase in Pentachletera macrophylla during ugba production. Low lipase activity in some fermented
foods has been considered desirable because of problems of objectionable taste and development of
rancidity (Yong and Wood, 1977; Odunfa, 1983b, 1985b). However, there are reports of beneficial
effects of lipase in the developments of characteristic flavours and aroma
(Whitaker, 1978, Ouoba et al.2005). These results appear contradictory and require further study. An
interesting area would involve the effects of change of lipid quantity and quality on the organoleptic
characteristics of fermented condiments. Darweesh et al. (1991) have reported that aldehydes resulting
from oxidation of lipids cause off-flavour and odour problems.
However, organic solvent treatment of fermented condiments from locust bean, melon seed and
soya bean on the objectionable odour, did not show any appreciation of the odour (Arogba et al., 1995).
Not much can be said about the flavouring components of fermented vegetable proteins used as
condiments as no research has been carried out on this aspect. However, there is no doubt that amines,
peptides and glutamic acid all contribute to this flavour.
3.6 NUTRITIONAL QUALITY OF FERMENTED CONDIMENTS
Classical techniques for assessment of bioavailability of nutrients generally involve in vitro tests with
animals. Protein utilization measured as Protein Efficiency Ratio (PER) and the digestibility of soya
bean and some legumes are hardly improved by fermentation (Obizoba, 1998; Nout and Rombouts,
1990). It was reported that rats do not utilize proteins from fermented soybean any better than from the
cooked substrate. Nevertheless, some reports indicate otherwise. Achinewhu (1983)
reported that fermentation and heat treatment improved apparent digestibility, feed conversion
efficiency and protein efficiency ratio when rats were fed on diets of African oil bean seed rations.
Eka (1980) studied the effect of fermentation on the nutrient content of locust beans and reported that
protein and fat increased when fermented whereas the quantity of carbohydrates decreased. Increased
levels of the amino acids were also reported except for arginine, leucine and phenylalanine. Similar
results were reported for other seed legumes (Odunfa, 1985b; Achinewhu, 1988; Sarkar et al., 1998).
Soluble products increased during fermentation of melon seeds resulting in high digestibility of the
fermented product. Alanine, lysine and glutamic acid were the predominant amino acids, with arginine
and proline occurring in small amounts (Odunfa, 1983a; Aidoo, 1986). The improved nutritive values
were attributed to the increase in amino acid profiles due to
fermentation.
Food condiments made from vegetable proteins maybe a good source of certain B vitamins, but
are deficient in ascorbate and some fat-soluble vitamins, which are lost during fermentation.
Achinewhu and Ryley (1986) have shown that fermentation significantly increased the content of
thiamine, riboflavin and niacin in the African oil bean. Similar changes were observed during the
fermentation of melon seed and fluted pumpkin seed (Achinewhu, 1986a,b). Ogbonna et al. (2001)
observed increases in calcium, phosphorus and potassium when African yam bean was fermented for
condiment production. This is in contrast to previous results of Achinewhu (1986b), which reported
decrease in calcium, copper and phosphorus but increased iron and zinc in fluted pumpkin. It is evident
that fermented food condiments is a good source of nutrients and could be used to produce
complementary food supplements. Macronutrients in fermented legumes contribute to enhanced food
quality.
3.7 FUTURE OF FERMENTED CONDIMENTS IN NIGERIA
A substantial literature documents the successful fermentation of vegetable proteins for condiment
production. Both microbial and biochemical changes involved therein have received much attention.

17. 17
A further understanding about the interactions of the microorganisms and plant materials is necessary
to improve the quality of fermented condiments. Such understanding will aid in further development
and control of the fermentation process.
Selection of starter cultures for large-scale industrial processes may require genetic
modification to introduce a number of properties. These may offer nutritional benefit in the form of
increased protein production or compatibility to mixed culture fermentations. Fermented
condiments have a characteristic organoleptic quality, which probably are the most important factors
for consumers. There are a few data on the flavour components of fermented condiments and how this
can be improved by fermenting microorganisms (Dakwa et al., 2005). Further research is needed in
these areas.
Taking into account the increasing demand particularly by urban populations in Nigeria, there
are certainly prospects for industrialization of traditional fermented condiments. Commercial
availability of ready-to-use fermented products saves much labour and time in the household (Nout and
Sarkar, 1999). Better control of fermentation and quality of fermented foods is required in the scaling
up process. Mention was made already of the choice of raw materials, fermentation conditions, and
starter cultures used (Achi, 2005).

18. 18
CHAPTER FOUR
4.0 CONCLUSION AND RECOMMENDATION
4.1 CONCLUSION
The importance of traditional fermentation of soybean for Iru production cannot be
overemphasized. Ogiri or Iru an important Nigerian indigenous fermented food condiment when used
in a soup imparts a desirable flavour and enrichment to the soup. Iru from soybean has also high
protein content having made from soybean, which has about 40% protein content as reported in the
literature. However, Iru as well as other traditional indigenous foods are produce under primitive
condition which results in low yield and poor quality product. Women and some men engaged in the
production activities. The techniques they use are labour intensive, time consuming, have low
productivity and have a wide range of variations as regards to product quality due to lack of
standardization. This is a need for improvement in order to upgrade the product.
4.2 RECOMMENDATION
In order to upgrade Iru production, there should be change from Craft to a Technology based
production system. Several strategies should be adopted, which include:
 The use of starter cultures for production
 There should be stabilization of spontaneous fermentation and
 There should be production of food processing enzymes
 In addition, there should be Raw material development
 The use of Genetic engineering
 Process development
 Finished product development
These will go a long way to upgrade Iru production and traditional food fermentation as a
whole. Indigenous fermented foods are produced at the household level in a majority of African
countries. Increasing industrialization and urbanization trends in these countries will however dictate
the need for larger scale production of fermented foods of consistent quality. Additionally, variation of
the quality attributes of these foods to meet the demands of the sophisticated and varied palates of
industrialized communities will eventually be required.

19. 19
Upgrading the production of fermented foods from the household to the industrial level will necessitate
several critical steps:
1. Isolation and identification of the microorganisms associated with the fermentations
Microorganisms associated with indigenous fermentations need to be isolated, properly identified and
preserved preferably in a recognised culture collection for future use.
2. Determination of the role(s) of the microorganism(s)
The biochemical role(s) of microorganisms associated with food fermentations needs to be determined
through chemical analysis of products released by the microorganisms under controlled laboratory
conditions.
3. Selection and genetic improvement of microorganisms
Microorganisms responsible for effecting important changes in the food during fermentation should be
selected and subjected to genetic improvement geared toward maximizing desirable quality attributes
in the food and the limiting any undesirable attributes.
4. Improvement in process controls for the manufacture of fermented foods
Improvements in the quality and quantity of fermented foods may be achieved by manipulating
environmental factors such as temperature, moisture content, aeration, pH, acidity etc. which influence
the activity of microorganisms during the fermentation process.
5. Improvement in the quality of raw materials used in the production of fermented foods
Both the quality and the quantity of fermented foods may be improved by choosing raw materials other
than those traditionally used for their production.
6. Laboratory simulation of the fermented foods
Prior to pilot scale production, and (ideally) after all the five stages above have been well studied,
fermented products may be produced under laboratory conditions. Laboratory simulation of fermented
foods will involve the production of fermented foods by innoculating microbial isolates having
desirable properties, into raw materials.
7. Pilot stage production
The pilot stage is the first clear departure from small scale production and should be based on the result
of laboratory experiments.
8. Production or industrial plant stage
The production stage is the culmination of all the previous efforts and should lead to the availability of
food of predictable and consistent quality on a large scale.

20. 20
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