nigerian indigenous fermented foods: their traditional process

ELSEVlER

Food Rrscwch Infernutionol~ Vol. 29, Nos 5-6, pp. 527-540, 1996 Copyright 8 1996 Published by Elsevier Science Ltd

on behalf of the Canadian Institute of Food Science and Technology Printed in Great Britain

0963-9969196 $15.00 + 0.00 0963-9969(95)00045-3

Nigerian indigenous fermented foods: their traditional process operation, inherent problems, improvements and current status

Chinyere I. Iwuoha* & Onyekwere S. Eke

Department of Food Science und Technology, Federal Universit_v qf Technology, Owrrri, P.M. B. 1526. Owrri. Imo State, Nigeriu

Nigerian indigenous fermented foods (NIFF) are reviewed in this report outlin- ing their traditional status as well as any significant scientific and/or technological steps or modifications introduced towards developing them to the status of modern processed food. The NIFF consist of a wide range of products sourced from cereals (‘burukutu’, ‘pito’, ‘kwunu’, ‘ogi’, ‘otika’), fruits (‘agadagidi’, cacao wine, ‘eketeke’, ‘ugba’), legumes (‘daddawa’, ‘iru’. ‘ogiri’, ‘ogboroti’), tubers (‘abacha’, ‘elubo’, ‘fufu’, ‘gari’, ‘loiloi’, ‘kokobele’). tree sap (‘ogogoro’, palm wine), meat and seafoods (‘afonnama’. ‘azu-okpo’, ‘nsiko’. ‘oporo’), and milk (‘maishanu’, ‘nono’, ‘warankasi’). The problem inherent in the technology of their process operations forms part of the characteristic features of the traditional family and/or ethnic method of fermenting local staples. These were found to result from the following limitations associated with different aspects of indigenous fermentation processes, thus: a production environment which fails to observe good manufacturing practice (GMP) or code of hygiene; lack of knowledge of the culture of the process(es) and their characteristics; absence of any control in that the processing variables like pH, temperature, humidity. and quality of water were then unknown and were unable to be used to regulate the process; lack of awareness of the nutritional and/or toxicological implications of fermentation and its products. Development came up as results of assessing the characteristics of the NIFF systems with a view to improving on the equipment, substrates, culture as well as process control and product quality. These efforts have yielded a reduction in the duration of fermentation, and emergence of products that were free of health risks and which were of consistent quality capable of mass production through the use of mechanized equipment and sterile packages. These include ‘dadawa’ cubes, bottled palm wine, packaged dry cassava flours, ‘gari’, ‘soy-ogi’ and palm oil. Copyright c 1996 Published by Elsevier Science Ltd on behalf of the Canadian Institute of Food Science and Technology

Keywords: Nigerian indigenous fermented foods, traditional process operations, inherent problems, research, assessment, microbiology, process control, nutritional, toxicological, improvement, development, current status.

I. INTRODUCTION

Chemical changes in foods brought about by enzymes from living microorganisms constitute fermentation. It

has been established that there are nutrient-rich crops in Nigeria which are fermented and used as foods or as food condiments (Collard & Levi, 1959; Akinrele, 1970;

*Author to whom correspondence should be addressed.

Ekundayo, 1977; Onyekwere, 1977; Ogundiwin, 1978a,b; Tehinse & Ogundiwin, 1978; Achinewhu, 1983a,b;

Kuboye, 1985; Odunfa & Oyeyiola, 1985; Pierson et al.,

1986; Uzogara et al., 1990).

Generally, these crops are not used as foods in their unfermented state because some of them contain toxic

or anti-nutritional factors. Fermentation leads to a gen- eral improvement in the shelf life, texture, taste, aroma, as well as nutritional value (Kuboye & Akinrele, 1977; Odunfa & Oyeyiola, 1985; Uzogara et al., 1990).

528 C. I. Iwuoha. 0. S. Eke

The Nigerian indigenous fermented foods (NIFF) constitute a group of foods that are produced in homes, villages and small scale cottage industries. They are sold to the rural populace who buy them for food and social ceremonies. The fermented foods are derived from substrates like roots, legumes, cereals, oilseeds, nuts, meat, fish, milk, palm tree, sap, etc. (Oguntunde, 1989; Uzogara et al., 1990; Akobundu & Iwuoha, 1992).

In the distant past, there were no verified data on the economic, nutritional, technical and quality control implications of the NIFF. Only recently have food technologists, human nutritionists, microbiologists and other applied scientists carried out multi-faceted, com- plementary studies on NIFF so that developments can be achieved.

The aim of the present paper is to present the NIFF in their traditional preparation and uses and to discuss significant scientific or technological steps or modifications introduced in NIFF towards improvements and/or advancements which contribute to development.

2. INDIGENOUS FERMENTED FOODS IN NIGERIA

2.1. Classification and processing methods

Nigerian indigenous fermented foods (NIFF) can be classified according to the food groups from which they were derived.

2.1.1. Plan t-based The plant-based fermented foods consist of those sourced from cereal, legumes, fruits, tree crops and root and stem tubers.

2.1.1.1. Cereal-sourced (a) Pito and Burukutu ‘Pito’ is a cream-coloured liquor while ‘Burukutu’ is a brown-coloured suspension. Both are brewed concur- rently by fermenting malted or germinated single cereal grain type or a mixture of grains.

The method is thus: Soaking the grains for 1 day, draining of soak water, germinating for 2 days, sundry- ing, milling into flour, mixing the flour with water, boiling for 3-4 h to form slurry, settling and decanting, addition of fresh water and reheating for 3 h. The mixture is allowed to stand at room temperature for 24 h. More water is added and the mixture is reheated for 3 h. Cooling and separation follow. A supernatant and sediment are obtained which are allowed to ferment for 1 day at room temperature resulting in ‘pito’ (top clear supernatant) and ‘burukutu’ (a thick brown suspension), (Ekundayo, 1969, 1977; Faparusi et al., 1973; Uzogara et al., 1990). (b) ‘Kwunu-zaki This is a watery gruel made from fermented millet

paste and is very popular in northern Nigeria, where it serves as a breakfast dish.

To prepare it, the millet (Penn&e&m typhoideum) is ground in a mortar and pestle to remove the husk or testa and release the kernels. The kernels are washed and left to dry on a mat out in the sun. The dried kernels are ground into flour, which is then suspended in a little cold water and stirred into a pot of hot water - continuous stirring is effected until a thick smooth paste is formed. The paste is left to ferment and cool to ambient temperature for l-3 days, which leads to the development of a sour flavour (Uzogara et al., 1990). (c) ‘Ogi’ This is a fermented cereal gruel. Its porridge has a smooth texture and a sour taste reminiscent of yogurt, with a characteristic aroma (Umoh & Fields, 1981). Steinkraus (1983) quoted Banigo (1977) and Onyek- were & Akinrele (1977a) as reporting that the colour of ‘ogi’ depends on the cereal grain used for its production: cream-white for maize (Zea mays), reddish-brown for sorghum (Sorghum vulgare), dirty grey for millet. It serves as a weaning food all over Nigeria (Akinrele & Bassir, 1967; Banigo & Muller, 1972b; Okoli & Adeyemi, 1989).

The method of traditional Nigerian ogi production was reported by Steinkraus (1983) as described by Banigo et al. (1974). The cereal grains of interest are steeped in earthenware, plastic or enamel pots for l-3 days to ferment. The fermented grains are wet-milled and wet-sieved to yield the ogi slurry. In some communities there is a further optional fermentation for l-3 days after wet-sieving. (d) ‘Otika ’ ‘Otika’ is an alcoholic beverage traditionally brewed from sorghum malt and drunk in some parts of Nigeria (Tehinse & Ogundiwin, 1978).

The production method is thus: grains of the red variety of guinea corn or sorghum (Sorghum guineese) are malted as in the ‘pito’ production. Mortar and pestle are used to mill the malted sorghum into flour. The flour is suspended in water and boiled for at least 3 h, cooled and filtered. The filtrate is left at the prevailing room temperature to ferment for 3 days (or it may be inoculated with liquor from a previous ferment). The fermented beverage is again filtered using ‘ogi’ sieve cloth prior to consumption.

2.1.1.2. Fruit-sourced (a) ‘Agadagidi’ This is a fermented beverage prepared from soft, over- ripe banana/plantain.

The preparation method, according to Uzogara et al. (1990) and Abiose & Adedeji (1992) involves packing of peeled, sliced plantains/bananas in an earthenware pot and covering with water. The pot is covered tightly and allowed to ferment at room temperature for a period of l-5 days after which the juice is strained and

Nigerian indigenous fermented foods 529

used as a drink, ‘Agadagidi’, especially in southwestern unwrapped and salt is added, the wraps are replaced Nigeria. and fermentation is allowed for 1 day after which ‘ogiri- (b) Fermented cocoa sap ugba’ is ready for use as a soup flavouring. This is a common traditional alcoholic beverage produced from cocoa sap, drunk in Cross River State.

Oyo, Ondo and Ogun States of Nigeria. According to Uzogara et al. (1990) the preparation

simply involves: cutting open ripe cocoa pods (Theo- hroma cacuo), the seeds of which, with their surrounding

sugary pulp, are collected and placed in porous raffia baskets and covered with leaves. They are left to ferment

for 556 days. The fleshy cocoa pulp solubilizes and the

seeds are released; the sap (from the pulp) drips from the

porous baskets into a calabashiearthenware pot from where it is later consumed as a refreshing drink.

(c) ‘Eketeke’ This is fermented palm oil which is traditionally used in the preparation of ‘ugba’ (fermented African oilbean

seeds) salad.

2. I. I. 3. Legume and seed-sourced (a) ‘DuddaJva’ ‘Daddawa’ is a fermented soya bean (Glycine max Merrill)

product used as a food condiment in northern Nigeria, especially Abuja, Benue and Plateau States.

Production of ‘eketeke’ involves placing the freshly- harvested oil palm bunches in a shade, covering com-

pletely with leaves for 1 week to ferment. The fruits are removed, cleaned and pounded into a cake in a mortar

and pestle. The cake is dry-heated in an open cast iron

pan, and finally pressed to release the slightly ‘rancid’

fermented oil, having characteristic flavour (Uzogara et

al., 1990).

(d) ’ Ughu’ ‘Ugba’ refers to fermented oil bean (Pentaclethru macrophyllu) seeds which are utilized by the Ibo and some other ethnic groups in southern Nigeria as a deli-

cacy and soup flavouring (Ikenebomeh et al., 1986).

Its production is described by Uzogara et al. (1990)

thus: soya beans are sorted, cleaned and washed in water then soaked in water overnight. The seed coats are

removed and the cotyledons washed. The cotyledons

are boiled in water in an earthenware or aluminium pot for 2-3 h after which excess water is decanted. The

boiled kernels are placed inside a calabash container lined with blanched plantain leaves which are also used in covering the seeds. This is left to ferment at room

temperature for up to 5 days. It may also be wrapped

in small flat portions and smoked prior to pounding into flour for use in soup or stew.

(b) ‘Zru ’ ( ‘Dm~uduwu ‘)

‘Iru’ (Yoruba) [‘Dorowa’ (Hausa), ‘Ogiri-igala’ (Ibo)] is

an important food condiment and protein source pro-

duced from the fermented African locust bean (Purkia filicoideu Welw) (Campbell-Platt. 1980; Odunfa, 1981a;

lkenebomeh et d., 1986).

The processing of the large brown glossy seeds of the

African oil bean to obtain ‘ugba’ involves the following: oil bean seeds are boiled in water in a metallic pot

over an open fire for 4-12 h to soften the hard brown

testa (called the shell). The shells are removed and the kernels are washed. The kernels (cotyledons) are

boiled in water overnight over a low flame. allowed to cool, drained, and washed with cold water several

times. The washed cotyledons are cut into long thin slices. These slices are mixed with salt, wrapped in small packets with leaves and lightly tied. These are

placed in a basket to ferment at room temperature for 225 days to yield ‘ugba’. A three-day fermentation pro-

vides the delicacy, while 5 days of fermentation pro- duces the soup condiment (Odunfa & Oyeyiola, 1985; Pierson et al., 1986).

According to Odunfa (1985~) Steinkraus (1985) and Uzogara rt ul. (1990). ‘Iru’ is produced thus: locust

bean seeds are boiled for between 12 h and 2 days to soften the hard seedcoats after which they are dehulled by

hand or by gentle pounding. The separated cotyledons are boiled in water with ‘kanwu’ (potash) for 2 h to

soften them. The boiled cotyledons are spread in a raffia basket lined with blanched banana leaves and the

cotyledons are covered with several layers of banana leaves and left to ferment for 2 to 3 days at the prevail-

ing temperature of the day. Wood ash may be added. The fermented product is then sun-dried for l-2 days

yielding a dark brown or black product. Alternatively,

before use, the sun-dried mass can be made into a paste of varying shapes and textures depending on the cus- tom of the ethnic group consuming it.

(c) ‘Ogiri-ep.ri

‘Ogiri-egusi’ is a condiment prepared from melon (Cit-

rullus wlguris Schrad) seeds through fermentation. It is

used as a flavouring in sauces, soups and stews in eastern Nigeria (Achinewhu, 1987h).

‘Ogiri-ugba’, is a food condiment prepared from 3-day

fermented oil bean seeds described earlier. To prepare this, according to Uzogara et al. (1990), the fermented

slices are pounded/blended into a meal and mixed until a creamy paste is produced. Some charcoal powder is added (optional) to impart a black colour, and the paste is wrapped in small portions with blanched banana leaves, placed in a raffia basket and hung above the fireplace in the kitchen. After 2-8 h the leaves are

The preparation method as reported by Steinkraus (1985). Iwuoha & Onuoha (1988) and Barber & Achinewhu (1992) involves the following: melon seeds

(dry) are moistened and dehulled. The cotyledons are then boiled for 2-3 h, the boiled seeds are wrapped tightly in layers of blanched plantain leaves, and left to ferment at the prevailing ambient temperature for 335 days. At the

end of the fermentation period, the seeds are ground into a paste with ash from burnt oil palm leaves and

530 C. I. Iwuoha, 0. S. Eke

palm shaft is added to impart a grey colour to the paste. The paste is distributed in small portions into leaves, wrapped up and left near the hearth (fireplace) until the unique (characteristic) aroma of ‘ogiri-egusi’ develops. (d) ‘Ogboroti’I’Agbaratii’ This is fermented African oil bean seed-melon mix used as soup flavouring or as delicacy when boiled.

According to Uzogara et al. (1990), the preparation is effected thus: oil bean seeds and melon seeds are fermented separately for 3 days. Equal measures of the two are mashed together to make a paste. The paste is distributed in small portions into blanched leaves which are wrapped and placed near the fire for proper flavour development, giving rise to ‘ogboroti’. (e) ‘Ogiri-isi’ This is also known as ‘ogiri-igbo’ and ‘ogiri-agbor’ (Odunfa, 1985a). It is a condiment prepared from fermented castor seeds (Ricinus cummunis) and used in soups and stews in eastern Nigeria (Achinewhu, 1987a).

The preparation according to Anosike & Egwuatu (1981) and Uzogara et al. (1990) is thus: the castor seeds are dehulled, the dehulled seeds are wrapped in blanched plantain leaves and boiled in water for 6-8 h. The boiled seeds which are still wrapped in the leaves are left for 4-6 days to ferment. Later the seeds are mixed with ash from burnt palm leaves and then ground into a paste. The resultant paste is re-wrapped and left for another 3 days near the fire to develop the characteristic flavour (aroma) of ‘ogiri-isi’. (f) ‘Ogiri-ugu ’ This is also referred to as ‘ogiri-nwan’. It is the fermented product from fluted pumpkin (Telfairea occi- dentafis) beans. It is produced and used as a soup flavouring in southeastern Nigeria (Odunfa, 1985; Achinewhu, 1987a).

The production of ‘ogiri-ugu’ involves extraction of bean seeds from the pod, boiling for 2 h in water to soften the seedcoat after which the dark coloured water is discarded. The cotyledons are washed and placed in a pot, covered and left near the fireplace for 2 days to ferment and soften. They are then ground into a paste, wrapped in small portions in leaves and placed near a fire until used (Uzogara et al., 1990).

2.1.1.4. Tree sap - sourced (a) ‘Ogogoro ’ ( ‘Kaikai’) ‘Ogogoro’ is a highly alcoholic liquor obtained through the distillation of fermented palm wine (Kuboye, 1985; Uzogara et al,, 1990).

According to Uzogara et al. (1990) the sap tapped from the various palm viz: raphia palm (Raphia hookeri., R. vine-j&a) and oil palm tree (Efaeis guineensis) (Kuboye, 1985), is fermented under the prevailing ambient temperature of the room for 7 days before distillation. The distillate is ‘ogogoro’. (b) Palm wine Palm wine is the fermented sap of palm trees, either

raphia palm (‘mmanya-ngwo’) or oil palm (‘mmanya- nkwu’) (Uzogara et al., 1990; Uzochukwu et al., 1991).

According to Kuboye (1985) and Uzogara et al. (1990), the palm sap is obtained by the tapping of the inflorescence of these palm trees. The sap is left to ferment for a few hours and the fermentation is complete in about 2 days, giving rise to a milky suspension of microorganisms in a fermented sap that tastes sour and harsh.

2.1.1 S. Tuber - sourced (a) ‘Abacha ’ ‘Abacha’ or ‘Akpu-mmiri’ refers to wet cassava chips consumed as a popular snack in southeastern Nigeria.

To prepare ‘abacha’, the cassava root tubers (Mani- hot escufenta Crantz) are washed, peeled, boiled in water for about 1 h and cut into longitudinal slices or chips. These chips are steeped in water for l-2 days during which the water may be changed once or twice. At the end of the fermentation (during which the taste of the chips becomes almost bland), the chips are finally washed two or three times with fresh cold water. An alternative handling for long term storage is to dry the chips under the sun for several days (Uzogara et al., 1990). (b) ‘Efubo ’ This is also called ‘lafun’ (Kuboye, 1985; Uzogara et al., 1990). It is a fermented cassava dry flour commonly consumed in the western states of Nigeria.

The production involves peeling of cassava roots, washing and cutting into chunks. The chunks are soaked in water in pots or at edges of stream and left for 34 days to ferment and soften. At the end of fermentation the softened chunks are dried under the sun for 2 days, ground and sieved to produce ‘lafun’ or ‘elubo’ (Uzogara et al., 1990).

According to Kuboye (1985), another method involves soaking of cassava roots to ferment after which they are peeled, dewatered, sun-dried, milled and sieved to yield ‘lafun’. (c) ‘Fufu ’ ‘Fufu’ (also called ‘utara akpu’) is the meal of soaked fermented cassava roots which is widely consumed in eastern Nigeria.

The production is effected thus: the tubers are peeled, washed, cut into thick chunks and steeped in water in earthenware pots or in a slow-flowing stream for 4-5 days to ferment, soften and produce a characteristic of retted cassava meal. The tubers are dis- integrated in clean water, sieved and allowed to settle for decantation of water. The sediment is the ‘fufu’ (raw) which can be consumed by hydrothermal gela- tinization to form stiff dough (Hahn, 1989; Uzogara et al., 1990). (d) ‘Gari’ ‘Gari’ is a granular starchy food made from the bitter variety of cassava root (Manihot utifissima Pohl; M.


esculenta Crantz) tubers by fermenting the grated pulp, followed by semi-dextrinizing, drying, and grading (Ogunsua, 1977; Okafor, 1977~; Onyekwere & Akin- rele, 19776). It is popular among Nigerians, especially in the south (Uzogara et al., 1990).

Nigeria, as well as the Lake Chad area of northern Nigeria.

The traditional gari production procedure involves peeling of cassava roots, grating into fine pulp using aluminium sheets perforated with nails and fixed on wooden frames. The grated pulp is placed in Hessian sacks which are tied up and compressed with heavy stones or wood. The sacks are left outside or under a shed to drain and ferment for up to 4 days. The fermented pulp, which is semi-dry and harsh to taste, is sifted using hand-made fabrics, and the finer grains are toasted (with or without palm oil) on shallow cast iron pans heated on an open fire, sifted again and packaged (Collard & Levi, 1959; Okafor, 1977~; Onyekwere, 1977; Kuboye, 1985; Steinkraus, 1985; Hahn, 1989; Uzogara et ul., 1990). (e) ‘Loi-loi ’ ‘Loi-loi’ is a kind of ‘fufu’ which is popular among the Riverine States of Nigeria, especially Rivers, Cross River and Akwa Ibom States.

The processing varies but basically consists of hang- ing the product at the prevailing tropical climate as conditioning prior to preparation for final consumption or spreading in a thick heap to dry for l-5 days, during which fermentation takes place resulting in the development of a characteristic aroma. Examples of products produced from this process are beef tripe (‘afonnama’), fish (‘azu-okpo’), crab (‘nsiko’), crayfish or shrimp (‘uponi’ or ‘oporo’) (Uzogara et al., 1990).

2.1.2.2. Milk-sourced (a) ‘Muishanu ’ and ‘Nono ’ These are the soft butter and cheese, respectively obtained from fermented cow’s milk, common in northern Nigeria.

The preparation is thus: cassava roots are peeled, washed, and soaked for 2 days in water to partially soften and ferment them. The roots are then ground into a paste using the village mill. The paste is mixed with fresh cold water and left to ferment for 1 day. Sieving is carried out to obtain a crude starch suspension. This is put into a cloth bag and dewatered resulting in starch which can be dispersed in a little cold water and stirred into hot boiling water until a smooth paste (stiff dough) is formed to produce prepared ‘loiloi’ (Uzogara et al., 1990). (f) ‘Kokobele’ This is a dried flour derived from fermented cocoyam tubers - the tannia variety (Xanthosoma sugittlfolium). It is usually reconstituted in water and boiled with pep- per, tomatoes, palm oil, fish and spices to enhance its flavour. It is a common food in Ondo State in western Nigeria.

Fresh raw milk from cow is boiled for up to 3 h and allowed to stand for 1 day at room temperature inside a calabash pot. Butter floats on top of the suspension while sediments (cheese) are also obtained after decantation. The soft butter is ‘maishanu’ while the cheese is moulded to give ‘nono’ (Uzogara et al., 1990). (b) ‘Wurankasi’ This is a soft unripened cheese obtained by fermenting milk from either goat or cow. This food is popular among the Fulanis.

It is produced thus: the cocoyam tubers are peeled, washed, sliced and steeped in water at room temperature, and left to ferment for 2-3 days. At the end of fermentation the steep liquor is drained off and discarded while the cocoyam slices are sun-dried for 3-5 days and then milled into flour, giving rise to ‘kokobele’ (Uzogara et al., 1990).

According to Ogundiwin (19786) Uzogara et al. (1990) and Fashakin & Unokiwedi (1992), ‘warankasi’ is produced thus: milk is manually drawn from the animal udder and mixed with some drops of the juice from the leaves, buds or stems of the Sodom apple plant (Calotropis procera). The mixture is allowed to sour by a natural fermentation at ambient temperature for over 12 h. The fermented mixture is heated gently for 40-75 min during which the contents form a junket. This is allowed to ‘break’ or form a streak on the sur- face scum which is carefully removed with a calabash scoop and the white curd is exposed. Intensified heating is carried out to stop the (enzyme) activities, to allow for flavour development and texture formation in the finished product. The resulting ‘wara’ is put into moulds and the whey is allowed to drain off for a few minutes. The carrot-shaped cheese is thrown back into its whey from where it is consumed.

Table 1 shows the distribution of NIFF in Nigeria at a glance.

2.1.2. Animal- and seajbod-based The animal- and seafood-based foods are made up of the fermented foods sourced from flesh and milk.

2.2. Problems associated with Nigerian indigenous fermented food (NIFF)

A critical view of the NIFF as they are used in traditional family or ethnic arts reveals that the production processes are laden with problems. 2.1.2. I. Flesh-sourced

Meat and fish products with strong smells resulting The problems can be considered in the categories of from fermentation are used as soup flavouring and in production environment, microbiology in processing, certain other dishes along the coastal areas of southern process control, and nutritional and toxicological status.


Table 1. Distribution* of indigenous fermented foods (NIFFs) in Nigeria

Class of foods NIFFs Specific food sources Indigenous places

Cereals Burukutu and Pito Sorghum, Maize North, Mid-West Ogi Maize East, West

Fruits Agadagidi Over-ripe plantain or Banana South-West Cacao wine Cocoa pod pulp South-East, West Ugba African oilbean cotyledons South

Legumes Iru (Dawadawa) African locust bean North Daddawa Soya beans Middle belt Ogiri-egusi Melon seeds East Ogiri-isi Castor oil seeds East Ogiri-ugu or Ogiri-nwan Fluted pumpkin seeds South-East

Tree sap Palm wine Raphia palm or Oil palm tree South

Tuber Gari Cassava roots South, North Fufu Cassava roots East Lafun Cassava roots West Abacha Cassava roots East, South-East Elubo Cassava roots West Loiloi Cassava roots Riverine States Kokobele Cocoyam corms West

Afonnama Beef tripe East, Mid-West Azu-okpo Fish South Nsiko Crab South Uponi or Oporo Crayfish or shrimps South

Milk Maishanu and Nono Cow’s milk North Warankasi Goat/Cow milk North (Fulani)

*The places listed are birthplaces for the arts of production and predominant utilization but inter-ethnic/state trades and relocation have widened the scope of the spread of each NIFF throughout the country and beyond.

Flesh

2.2.1. Production environment In our traditional setting where the production level

is that of subsistence housekeeping, the processing

environment is very unpredictable: the equipment used is rudimentary (calabash, earthenware, leaves, baskets and cloth), the hygiene of handlers, equipment and facilities is not checked, the water used, especially at the edges of streams cannot be said to be potable; tropical climate (temperature and humidity) cannot be said to be the optimum for all fermentation and storage purposes. All these factors affect the quality of final product and the health of ultimate consumers.

2.2.2, Microbiology of process A lot of the information was flawed - there was no way to assure a consistently uncontaminated environment for the fermentation: the microbial composition of the inocula was unknown - identification of type, the identity of the contaminating microbes, the age and purity of each culture, the predominant microbes, and the conditions of pH, temperature, ionic strength, information on foods that best favoured the microbial performance in fermentation.

2.2.3. Process control In view of the limitations in NIFF as outlined in section 2.2.1 above, and also because there was no sci-

entific protocol in food process operations, the practice of process control was virtually impossible to maintain. Fermentation periods were chosen according to human judgement. The quality and quantity of water and substrate to be used was not regulated or standardized, heating processes were not controlled or measured. All the above-mentioned factors resulted in inconsistent quality.

2.2.4. Nutritional toxicological status The lack of knowledge or information on the effect of fermentation on the nutritional quality of the final products stood as a problem in that consumers were unaware of the actual nutritional worth of the foods except the organoleptic attributes. Also the type and degree of danger posed by the consumption of fermented products which are unfit for human consumption due to the handling process or post-fermentation contamination were not known, Any death resulting from these above-named sources could not be established conclusively.

2.2.5. Basic food preservation ethics Local processing centres will have to be established in order to control or forestall the inherent problems (2.2.1-2.2.4) and their perpetuation. At the moment, health personnel from some government hospitals from time to time organise good manufacturing practice


(GMP) and basic hygiene workshops for the women and girls who engage in street foods trade and sell NIFFs and other ‘ready-to-eat’ foods (Oguntunde, 1989) in school premises. The impact of this training is not far-reaching because it does not touch all the diverse NIFFs being distributed to consumers and the staff involved are not grounded in food processing technology. They are mostly home economists, medical microbiologists and dietitians.

3. IMPROVEMENT IN THE NIGERIAN INDIGENOUS FERMENTED FOODS

The advent of education, training and specialization affecting some Nigerians and other interested foreign nationals in the fields of food microbiology, food science, biochemistry, human nutrition, fermentation technology, food processing and related fields coupled with very little data on the significance of Nigerian indigenous fermented foods (NIFF) led to the modern development in this area of traditional food processing and preservation technology.

These new food researchers set out to carefully identify methods involved in fermentation and the features of the original/traditional treatment and uses of the NIFF as well as the problems associated with those foods (see section 2 above). The next efforts were to study the indigenous fermentation processes in order to assess the characteristics (Table 2) with a view to introducing systematic modifications with resulting improvements in various aspects of the NIFF technology (Table 3).

3.1. Scientific evaluations of characteristics of NIFF processes

Systematic studies have been carried out over the years to evaluate the characteristics of the cultures involved in NIFF (Table 2). Also the biochemical, nutritional and toxicological changes in the food systems brought about by fermentation have been assessed.

3. I. 1. Microbial assessments

Microbiological studies were carried out to determine the cultures and their characteristic features as regards the following NIFF: ‘Agadagidi’ (Abiose & Adedeji, 1992) ‘fufu’, ‘gari’ and ‘lafun’ (Collard & Levi, 1959; Okafor, 1977b; Oyewole & Odunfa, 1988) ‘ogi’ (Akin- rele, 1970; Banigo, 1977; Onyekwere & Akinrele, 1977a; Odunfa & Adeyele, 1985) palm wine (Faparusi, 1971, 1973; Okafor, 1975, 1978; Ojomo rt al., 1984; Uzochukwu et al., 1991) ‘pito’ and ‘burukutu’ (Ekun- dayo, 1969; Faparusi et al., 1973), ‘ugba’ (Odunfa & Oyeyiola, 1985; Pierson et nl., 1986). The key findings are presented in Table 2.

3.1.2. Assessments of the biochemical and related changes

Research on biochemical and related changes in NlFF

have been conducted by several workers concerning different food groups.

Cereal-based the production of lactic, acetic and butyric acids (the main acids contributing to the desired flavour or sourness of ogi) have been found to be directly effected by Lactohacillus plantarium, the predominant organism in the fermentation (Banigo & Muller, 1972a). During fermentation, hydrolysed starch of maize is converted to organic acids at reduced pH (Akinrele, 1970).

When the ‘otika’ wort was separately inoculated with cultures of baker’s yeast (Saccharomyces cerevisae),

brewer’s yeast (S. carlsbergensis) and palm wine trub, all samples reached < 50 ‘%I attenuation in less than 30 h (Tehinse & Ogundiwin. 1978).

Fruit-bused NIFF: results of gas-liquid chromato- graphic (GLC) analysis of ‘Agadagidi’ process showed that methanol was formed and predominated in the first 2 days but was replaced by ethanol from the third to the last (5th) day of the fermentation.

In the production of cacao wine, Adesioye (1991) observed that cocoa pod (fruit) juice containing 18.6 ‘XI soluble solids, yielded up to 10.5 ‘%I alcohol (v/w) at the end of fermentation even when Succhurom~~ces .spp isolated from oilpalm sap or cashew juice were used.

During ‘ugba’ processing, fermentation was found to cause reduction in its minerals (Ca, Mg, K and P) contents (Achinewhu, 1983~) effect substantial increase in thiamin (vitamin Bl), riboflavin (B2) and niacin (Achinewhu & Ryley, 1986) and also increased the protein content (Achinewhu, 1983~; Iwuoha & Ike, 1991). Soluble nitrogen increased, total unsaturated fatty acids increased (Achinewhu, 1986) which aided hydrolysis of protein, leading to increase in pH from 5.0 to 8.7 (Pier- son et ul., 1986). Alpha-amylase, proteolytic and lipoly- tic enzymes activities (which reached a maximum at 2436 h) were found to relate to changes in the chemical composition of ‘ugba’ (Njoku & Okemadu. 1989).

Legume-bused NIFF a sequence of microbial succession has been reported in ‘daddawa’ processing: Bacillus spp

were consistent throughout while StaphJVococcus spp

occurred only during the last 3 days of fermentation (Popoola & Akueshi, 1985). Achinewhu (1978~) observed that niacin, riboflavin and thiamin were produced during the fermentation of fluted pumpkin (‘ogiri-ugu’), and castor “1 seeds (‘ogn-i-n ). Also Achinewhu et ul. (1991) reported that free amino nitrogen (FAN) and total microbial counts increased during fermentation of melon seeds (‘ogiri- egusi’) and were at their maximum at 35°C 1 ‘%I NaCl and 43.2% moisture. Barber and Achinewhu (1992) reported that in ‘ogiri-egusi’, fermentation effected pH increase from 6.5 to 8.1 and that a combination of Bacillus sp and Alcali-

genes sp is capable of producing the quality characteristics of a good ‘ogiri-egusi’; that beyond the maximum titratable acidity (which occurs at 35°C about the 1st day), it decreases by as much as 27.42 ‘%I at the 7th day.


Table 2. Predominant microbes involved and their optimal conditions for activity in the Nigerian Indigenous Fermented Foods (NIFF)

Class of NIFF Predominant microbes Optimum conditions for Reference foods involved performance/fermentation

Cereals Burukutu and pito

Ogi

Fruits Agadagidi

Cacao wine

Ugba

Legumes ‘Dawadawa’/‘Iru’

‘Daddawa’

‘Ogiri-egusi

‘Ogiri-isi’

Tree sap Palmwine and ‘ogogoro’

‘Ogiri-ugu’/ Ogiri-nwan

Tuber ‘Fufu’, ‘lafun’ and ‘gari’

Lactic acid bacteria and feast

Lactobacillus plantarum, Streptococcus lactis, Saccharomyces cerevisiae

Brettanomyces intermedius, Kloekera apiculata, Candida tropicalis, C. krusei, Hansenula anomala, Pediococcus cerevisiae, L. mesenteroides, Staphylococcus epidermidis, Micrococcus leteus

Yeast

Bacillus subtilis, Staphylococcus spp, Micrococcus spp, Corynebacterium spp

Bacillus subtillis, B. Licheniformis, Staphylococcus saprophyticus

Bacillus spp, Staphylococcus spp

Bacillus subtillis, B. megaterium, jirmus, Esubherichia, Proteus, Pediocococcus & Acaligehes spp

Bacillus spp, Pseudomonas spp, Micrococcus. spp. Streptococcus

Sarcina lutea, Shizo-saccharomyces pombe, saccharomyces cerevisiae, S. fiurentius, S. chevelleri, S. makii, Leuconostoc mesenteroides, Lactobacillus plantarum. Sarcina lutea, Acetonacter, Leuconostoc dextranicum, Lactobacillus casei

2 days, 27” f l”C, pH 6.5-3.5

Bacillus spp, E. coli, Staphylococcus 3 days, 29”-30°C spp, Pseudomonas spp pH 8.1-6.5

Carynebacterium manihot, Geotrichum candida, Streptococcus lactis, Aspergilus niger, this, Rhodotorula spp, Penicillum spp, Leuconostoc spp, Klebsiella spp

3-5 days, 28’45”C, pH 4.2-3.6

pH 6-35-3.42, 1-3 days, 27°C f 1°C

4 days, pH 6.2-3.6, 27” + 1°C

3-5 days, pH 50-8.7, 25-33°C

3 days 35”C, RH.Sl%

4 days, 37” + 2°C

3 days, 29”-3O”C, pH 8.1-6.5

3 days, 29”-30°C pH 8.1-6.5

Ekundayo (1969), Faparusi et al. (1973), Chukwurah (1982)

Banigo & Muller (1972a), Banigo et al. (1974), Fields et al. (1981), Odunfa (1985a)

Abiose & Adedeji (1992)

Odunfa (1985a)

Obeta (1983), Kolawole & Okonkwo (1985), Odunfa & Oyeyiola (1985), Pierson et al. (1986), Njoku & Okemadu (1989)

Odunfa (1981a), Kuboye (1985).

Popoola & Akueshe (1985)

Odunfa (1981b), Barber & Achinewhu (1992)

Barber et al. (1988), Uzogara et al. (1990)

Bassir (1962), Faparusi (1971, 1973), Okafor (1974), Ojoma et al. (1984), Uzochukwu et al. (1991)

Odunfa, (1985a), Barber et al. (1989)

Collard & Levi (1959) Okafor (19776), Onyekwere (1977), Oyewole & Odunfa (1988), Hahn (1989)

Tuber-based: during cassava processing, linamarin is hydrolysed in the presence of native linamarase to glucose and cyanohydrin, and subsequently the latter is broken down to acetone and hydrocyanic acid by hydroxynitrile lyase. At pH 5-6, free cyanide is released, more rapidly under gentle heating of the cassava mash (Oke, 1984; Cooke and Cock, 1989).

Animal (milk)-based: the active enzyme in the processing of ‘warankasi’ is calotropain, which hastens the coagulation of milk protein to yield a curd (Ibiama & Griffith, 1987). The composition, biochemical and chemical characteristics of the product depend on method employed and composition of milk (Ogundiwin & Oke, 1983, 1985).

Nigerian indigenous .fermented foods 535

Table 3. Some improvements introduced in the processes/products of the Nigerian Indigenous Fermented Foods (NIFF) ______-

NIFF Highlights of some improvements in the processes/products Reference/Source

‘Ogi’ (a)

(b)

(c)

(d)

‘Gari’ (a)

(b)

(c)

Use of improved grains, pure culture and coupled with mechanised handling of operations to improve organoleptic quality of product. Steeping of whole grains in hot water to soften them prior to milling to reduce steep duration.

Banigo rt al. (1974) Adeniji and Potter (1978) Banigo & Adeyemi (1975)

Use of dry-milling of maize in ogi production as a convenient method. Umon & Fields (1981) Adeyemi ( 1983)

Use of boiling to replace steeping of grains leading to the production of acceptable ogi within 24 h as against the traditional 72-96 h. Sokari et (I/. (1991)

Use of 4-day culture as starteriinculum to effect fermentation in 24 h on a succeeding cassava root tuber steep. Achieving longer shelf-life in gari through mechanised system with hygienic Collard & Levi (1959) processing environment, better sizing of particles and packaging of end product. Onyekwere (1977) Use of process variables to control fermentation process. Steinkraus (1985)

Palm-wine Use of sterile implements as well as introduction of pure culture to effect fermentation for consistent quality palmwine production. Uzochukwu et ul. (1991)

3.1.3. Nutritional assessments Several workers have assessed the nutritional levels and qualities of some of the NIFF products.

Cereal-based: during the fermentation of ‘ogi’, phos-

phorus is released from phytate (Lopez et al., 1983). During this period, niacin and riboflavin contents are

increased (Kuboye, 1985). Furthermore, in a feeding trial with 50 suckling rats at birth, the pups became

malnourished and most of them died, showing that ‘ogi’ was inadequate as a weaning food. Further analy-

ses showed that the indigenous fermentation process effected the following reductions (‘Xl) in the ‘ogi’: 13.86 (protein), lipid (9.33), fibre (53.95) and ash (38.46) (Ebuchi & Akinwande, 1991).

A report on ‘burukutu’ and ‘pito’ by Ihekoronye & Ngoddy (1985) suggested that fermentation enhances B vitamins in the drinks.

‘Otika’ was reported to contain maltose 18 mg ml ‘, alcohol 5.4% (v/w), sucrose 3.67% (w/v), and lactic acid 0.048% (w/v) (Tehinse & Ogundiwin, 1978). Fruit-based: Kuboye et al. (1978) reported that ‘agadagidi’ contains up to 6.57% alcohol. Fermentation improved the protein quality (Achinewhu, 19836) and nutritive value (Isichie & Achinewhu, 1988) of ‘ugba’. Legume-based: ‘Iru’ (‘dawadawa’) contains 18847% protein, 3143% fat (Eka, 1980). It is high in Ca, Fe and lysine but lacks methionine and cystine (Uzogara et al., 1990); it is also high in riboflavin (Odunfa, 19856). There is a marked increase in reducing sugars in ‘iru’ (Odunfa, 1985c) and ‘ogiri’ (Odunfa, 1982) due to fermentation. Tree sap-based fermented palm sap (palm wine) is a good source of biomass (protein/yeast), amino acids and organic acids (Uzogara et ul., 1990; Uzochukwu et al., 1991). Tuber-based: Gari contains (‘% d.b) starch (87,8), sugars (0,5), protein ( 1 .O), minerals (1. l), fibre (0.6) and lipids (0.1) (Oke, 1984).

Animal (milk)-based ‘Warankasi’ was reported to contain 4456% protein, 47.50% fat, ash 6.82%,, carbohydrate 1.12% (Fashakin & Unokiwedi, 1992). The protein efficiency ratio (PER) and net protein ratio (NPR) (Fashakin & Unokiwedi, 1993) were 92.80% and 89.73% of casein, respectively.

3.1.4. Toxicological and other health-related assessments Several studies have been carried out on the toxicological and other health-related status of some NIFF products: Cereal-based: there have been reports that fermented products involving Lactobacillus spp and lactic acid bacteria (LAB) have the following effects: viricidal (Gilbert rt al., 1983). anti-leukenic (Esser et al., 1983), antitumour (Oda et al., 1983; Shahani et al., 1983). This is important in that acidic fermentation processes of cereals in Africa (West Africa) have Lactobacillus spp and some LAB as the predominant micro-organisms (Akinrele, 1970; Okafor, 1979; Fields et al., 1981; Odunfa & Adeyele, 1985). Fruit-based: fermentation has been reported to consid- erably reduce/eliminate flatus-forming oligosaccharide (stachyose, verbascose, and raffinose) in ‘ugba’ (Achinewhu. 1986). There are strong indications of residual growth-depressing factors (e.g. caffeoyl-putrescine) in ‘ugba’ (Mears & Mabry, 1971; Mbadiwe, 1978, 1979). Legume-based traditionally-fermented castor oil seeds (‘ogiri-isi’) has been reported to be contaminated by fungi (Mazi & Ekwujuru, 1992) possibly from the processing environment. This is indicative of possible exposure of its consumer to mycotoxin (e.g. aflatoxin). Tree sap-bused: traditionally fermented palm sap (palm wine) has been reported to contain precursors of N-nitrosamines (nitrates, nitrites, and dimethylamine) which have carcinogenic potentials (Maduagwu & Bassir, 1979). ‘Ogogoro’ has a high (35.2%) alcoholic


content (Goma, 1989) which would expose consumers to intoxication. Tuber-based inadequate processing leads to residual cyanide up to toxic level (i.e. >50 ppm) (Coursey, 1973; Oke, 1984; Cooke & Cock, 1989). A nutritional problem (the tropical ataxic neuropathy) has been observed in Nigeria due to intake of cyanide (Osuntokun, 1973) while in eastern Nigeria, an endemic goitre associated with consumption of cassava diet has been reported (Ekpechi, 1973). However ‘gari’ has generally been noted for safe cyanide levels (i.e. << 50 ppm, Omueti et al., 1993) among cassava products. Miscellaneous: most processing/preservation operations of NIFFs frequently involve the use of a local food additive, ‘kanwa’ or trona (i.e. sodium sesqui-carbon- ate) which is known to be high in sodium (Uzogara et al., 1988). Hypertensives are exposed to greater danger when they consume these foods which are prepared with both the table salt and ‘kanwa’ because such foods become sodium-laden (Wilson, 1986). This situa- tion is of great significance especially as it is known that ‘kanwa’ is the second most used salt in Nigerian rural homes (Abiose and Adedeji, 1992).

3.2. Efforts to upgrade NIFF technology

Over the years, systematic and deliberate efforts were made by researchers through the introduction into some of the NIFF processes well co-ordinated trials to cause improvements through hygienic handling by the use of sanitary facilities (Onyekwere, 1977; Uzochukwu et al., 1991), production and utilization of pure culture (Collard & Levi, 1959; Banigo et al., 1974), process control by carefully manipulating process variables like inocula, pH, substrate quality, substrate particle size, temperature (Banigo et al., 1974; Onyekwere, 1977; Kuboye, 1985; Odunfa, 1985a; Steinkraus, 1985; Fashaki & Unokiwedi, 1993). Specific examples are shown in Table 3.

3.3. Effects of the scientific developmental efforts on NIFF technology

The results of the research and improvement efforts above brought the current state of development in the NIFF technology: the cumulative outcomes of the events reported above (see 3.2) are that processing/fermentation durations were drastically reduced in many instances; health risk-free, consistent-quality products were produced and preserved in packaged forms; products and processes were adapted to mass production.

New products with tested longevities are available in the market, (at least in the rural and urban Nigeria and West Africa), like ‘dadawa’ cubes (improved ‘dawadawa’ by Cadbury Nigeria plc based on the technology described in Figure 3), bottled palm wine (Nigerian Institute for Oil Palm Research, NIFOR, Benin, and

Federal Institute of Industrial Research, Oshodi, FIIRO, Ikeja), ‘soy-ogi’ (FIIRO), palm oil (NIFOR and LBN), cassava products (gari, flour, chips) (Onyek- were, 1977). Other processes and/or products that have been improved upon but not mentioned in this section are highlighted in Table 3 and Figures l-3.

The diverse endeavours made towards developing NIFF have resulted in the following levels of advance- ment: isolation of micro-organisms; determination of the roles of the organisms; selection and genetic improvement of organisms for improved performance; process improvement; improvement in raw materials used; lab- oratory simulation of NIFF production; pilot plant production; and industrial plant production.

Despite the establishment of small-scale gari industries which operate on the industrial principles as

Cassava

Peel

t Grate (Hammer mill)

Ferment in tanks

Centrifuge to remove water

Granulate and pass through BS 10 sieve

Gelatinize and toast (Garigy) heat to 80°C

Screen through BS 18 sieve

/ \

Gari Flour Mill coarse particles

Screen through BS 14 sieve

Gari

Fig. 1. Nigerian gari pilot plant process (Akinrele et al., 1971).


Maize

J (or millet or wrphum)

, Clean

/

Dchull -

(Palyi mill)

1

Hammer mill Elammer mill

1 1 Roller mill Roller mill

Whole grain flour Dehullcd flour

Ogi (uncooked)

Add water

i Boil

Ogi porridge

* Air separation

i Discard hulls

Cook

I

Cool

I

Inoculate

i

Incubate 32°C

74-2X hr

1

Ogi (partially cooked)w Dehydrate

Add water Dried instant Ogi

Boil Add water

t c Ogi porridge Ogi porridge

Fig. 2. Improved Nigerian ogi manufacturing system (Banigo rt al.. 1974).

specified by FIIRO (Adeyemi & Balogh, 1984) the

local manufacturers who still depend on the age-old traditional art still dominate the markets. The reason is

that their product is relatively cheap; only the top- bracket income group can purchase the modernized gari.

Dadawa cubes are inexpensive, and therefore, within the purchasing power of many individuals among the local and urban communities. Organised food prepara-

tion outfits like urban public canteens, schools and companies’ cafeterias/restuarants, and hospital kitchens utilize the modernized condiments.

The improved palm wine is more costly than the traditional type but cheaper than conventional beers: the rich choose it while the peasants, uneducated elders

Raw locust bean

i

Dchulling (Burr mill)

1

Boiling in retort

(15 Ih:\q in for I II)

c Draining and cooling (40°C‘)

c

Inoculation

(Dehydrated B. subtili\ spores)

1

Spreading on stainless \tcel tray\

lined with sterilized absorbent

paper

1

(‘ovcring with sheet of uaxed paper

I

Incubation (.i?“C)

c

Mixing with NaCl (7’~ w:w)

I

Drying in ;i vacuum

1

Packaging

1

DLlVG;ldaWLi

Fig. 3. Modern production of dawadawa (iru).

and community leaders (titled men) opt for the NIFF type, except when it is in short supply.

4. CONCLUSIONS

Nigerian indigenous fermented foods (NIFF), which

number about 30, are prepared from seven categories of local staples at the household and cottage level

through the traditional family and/or ethnic methods of

food processing and preservation. These NIFF have inherent problems as they were

processed and used in their purely traditional setting. Recently, Nigerians and some foreigners who acquired

expertise in the fields of food processing, human nutrition and health sciences have identified those problems,

set out and effected improvements so that currently a very substantial percentage of NIFF have been improved

to the status of modern processed foods.

ACKNOWLEDGEMENTS

The authors thank Dr J. 0. Uzuegbu for his encour- agements and Mrs 0. N. Nsofor for kindly providing relevant literature used in this report.


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(Received 19 September 1994; accepted 18 May 1995)

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