African cassava Traditional Fermented Food: The Microorganism


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Int.J.Curr.Microbiol.App.Sci (2016) 5(10): 664-687
International Journal of Current Microbiology and Applied Sciences
ISSN: 2319-7706 Volume 5 Number 10 (2016) pp. 664-687 Journal homepage: http://www.ijcmas.com

Review Article

http://dx.doi.org/10.20546/ijcmas.2016.510.074

African cassava Traditional Fermented Food: The Microorganism’s Contribution to their Nutritional and Safety Values-A Review

Guira Flibert*, Tankoano Abel and Savadogo Aly

Laboratoire de Biochimie et d‘Immunologie Appliquée (LaBIA) ; UFR-SVT, Université Ouaga I Professeur Joseph KI-ZERBO, Ouagadougou, Burkina Faso. 03 BP 7021 Ouaga 03 *Corresponding author

Keywords
Cassava; Fermentation; traditional Food; Folates, Africa.
Article Info
Accepted: 20 September 2016 Available Online: 10 October 2016

ABSTRACT
Cassava fermented food have a long story in Africa. There are consumed decades ago. Some cassava fermented food as gari are largely spread in the continent. Every part of the African communities has developed their own process to ferment and use cassava. Ubuswage, Imikembe, Ikivunde, Inyange, ivunde, Mokopa are known as East African cassava fermented food when Chikwangue, Meduame-Mbong, cossette are known as Central Africa speciality. In west Africa, cassava fermented food found are Gari, Attiéké, Placali, Lafun and efubo, Kokondé, Agbelima, Loi-loi, Attoupkou, Dumby, Abacha, Kapok pogari, Bêdêkouma. The associate or involved microorganisms include, Lactobacillus, Leuconostoc, Lactococcus, Enterococcus as lactic acid bacteria and Bacillus. Yeast and moulds found are mainly Candida, Pichia, Hanseniaspora, Trichosporon, Geotrichum, Zygosaccharomyces, Saccharomyces, Kluyveromyces,as yeasts, Aspergillus, Penicillium, Mucor, Rhizopus as moulds. The biochemical compounds produce during fermentation include folates, several organic acids volatiles organics compound and others compounds. Cassava fermented food preservation, the starch functional increase, aroma and flavour enhancement, anti-nutrients reduction as well as cyanogen reduction as known as the impact of the fermentation process. The health benefit of cassava fermented foods concern their nutritional value, probiotics properties and their contribution to human immune system increase. Cassava fermented food are still produce in artisanal way and don‘t allow their nutritional values standardisation.

Introduction
Cassava is a food plants brought from the New World to the Tropical Africa where it does now establish (Blench, 2014). The utilization of cassava as food for America‘s societies began around the 18th century before Christ (Blench, 2014). Cassava is grown widely in several parts of the world

especially in the tropical regions and constitutes a significant proportion of the diet of the population. In Africa, it provides over 50% of the average daily caloric intake in some countries (Oyewole and Odunfa, 1992).In recent times, a number of regional programs have been initiated to breed

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improved varieties of cassava (Guira et al., 2016) to increase yield and resistance to diseases which are sometimes associated with the indigenous cassava varieties (Silvestre, 1989). Several processes including fermentation are applied for cassava postharvest preservation. To date fermentation remains the most popular process of cassava by-products valuation. It improves food preservation, nutritional value, hygiene and sanitary qualities, the energy density and organoleptic characteristics of foods (Flibert et al., 2016).Fermented foods have a long history in Africa. However the absence of writing culture in most of Africa makes their origin difficult to trace(Odunfa (1988)).Some reviews have been written on cassava fermented food in Africa, showing some aspects of these foods. This review aim then to establish relationship between cassava main fermented food in Africa and their associate microorganisms properties, the nutritional function, safety values and health benefits for human nutrition.
Main cassava fermented food technology in Africa
Cassava fermented food in East Africa
Ubuswage
Ubuswage is one of the main cassava fermented food in Burundi. It probably originated in the Southern part of the country, where the production had been located. Ubuswage is now produces in other parts of the country (Aloys and Zhou, 2006b).The equivalents of ubuswage in other countries are the Chikwange of Congolese, Myondo and Bobolo in Cameroon, Mboung in Gabon and Mangbele in Central Africa Republic. Other similar foods are also found in Congo Brazaville, Soudan and Angola(Aloys and Zhou,

2006b). For Ubuswage preparation, fibers are removed from roots and cassava roots are then peeled, washed. After boiling, cooking water is discharged and cassava roots are disintegrated for fiber removal. Cooked cassava is soaked in water after defibrering it for three days up to two weeks. The soaking water is change every two days. After this fermentation period, the water is discharged and fresh water is added. The cassava roots are underwent a second cooking. Cassava are then poured in a trough and pounded while hot until a thick smooth paste is obtained. The gelatinized cassava mass is rounded, shaped and wrapped in plantain leaves previously flamed(Aloys and Zhou, 2006b). Ubuswage shelf life is ranged between seven to eight days. It depends on seasons. Ubuswage have a low content of cyanide but require more labor for processing and preparation than do other cassava fermented from cassava(Aloys and Zhou, 2006b; Aloys and Angeline, 2009).
Imikembe
Imikembe is a Burundi‘s cassava fermented food.Cassava roots used for Imikembe preparation are first peeled, washed and boiled in a pot. Fibers are then removed by disintegrating cassava boiled root. After fibers removal, cassava roots are peel, wash and cut into pieces.
These pieces are sun dried for a day and soaking for four days up to a week in covered batch for fermentation(Aloys and Zhou, 2006b; Aloys and Zhou, 2006a). During soaking process, fermenting water is change every two days (Aloys and Zhou, 2006b). The obtained product is dried for five days to a week. The final product called Imikembe is eaten with beans and some legumes(Aloys and Angeline, 2009).

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Ikivunde
Ikivunde is a similar cassava fermented food like the Democratic Republic Congolese cossette.Ikivunde is found in Burundi and Rwanda(Aloys and Zhou; Aloys and Angeline, 2009). It is a fermented flour with the main processes ofInyange, another Burundi‘s cassava fermented food. The cassava better varieties are usually used for ikivunde production. Cassava roots used for ikivunde preparation are peeled, washed and cut into pieces. But some other producers don‘t peel it. The obtained cassava roots are soaked in a stream or stationary water for at least three days up to a week to allow them ferment until they become soft. The fermented roots are taken out and then sun dried on mats, racks, or roof houses. The drying process may take three days to one week. The cassava fermented root, cossette are pounded and sieved to yield fermented withte flour called ikivunde(Aloys and Zhou, 2006b; Aloys and Zhou, 2006a; Aloys and Angeline, 2009; Uyoh et al., 2009; Muoki and Maziya-Dixon, 2010; Lambri et al., 2013)
Inyange
Inyange is a cassava fermented food mainly found in Burundi (Nzigamasabo, 2012). It is essentially due to moulds fermentation. Inyange is similar to ―mokopa‖, an Ougandan cassava fermented food. Cassava roots are peeled washed and cut into pieces. The pieces are sun-dried for a day. They are then heaped together and covered by plantain leaves or straw and left to ferment for five days. At the end of the fermentation, the pieces become soft and covered with moulds. The pieces are then scrapped, dried and pounded in a wooden mortar with a pestle and then sieved to get slightly dark colored flour: it is inyange. Inyange is made into a paste called ―ubugali‖ by stirring it

with boiling water over a low heat. It is usually eat with cassava leaves sauce, ―isombe‖ and meats. Inyange had been found to be nutritionally higher than ikivunde but it retains higher antinutrients(Aloys and Hui Ming, 2006; Aloys and Zhou, 2006b; Aloys and Zhou, 2006a; Nzigamasabo, 2012).
Kivunde
Kivunde is a traditional cassava fermented food which is produced and consumed as popular in Tanzania. Kimaryo et al., (2000) have described spontaneous and controlled process for kivunde production. Cassava roots are washed with water to remove all dirt and peeled, diced into cubes of roughly 1-3cm which were mixed. The cassava roots are again washed with boiled water. The roots are then submitted to the fermentation process for different time, from day up to a week according to the process (Lorri and Svanberg, 1995; Kimaryo et al., 2000; Mugula et al., 2003; Aloys and Hui Ming, 2006; Ray and Sivakumar, 2009; Anukam and Reid, 2009). By the end of the process, fermented roots obtained had a smooth texture and a pleasant fruity aroma.
Mokopa
Mokopa is a cassava fermented food from Ugandan, with mainly process like inyange(Ray and Sivakumar, 2009). Cassava roots used for mokopa production are first peeled and sliced. They are then surface dried for one to two hours before heaped together and covered with straw or leaves. The roots are submitted to three up to four days fermentation until the pieces become mouldy. The fermented and mouldy roots are again sun dried until the moulds have been scraped off. The processed and dried pieces are then milled into flour, mokopa which is prepared into a ‗‗fufu‖ called

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‗‗kowan‖ in Uganda (Hahn, 1992; Aloys and Angeline, 2009). The growth of moulds on the root pieces increase the protein content of the final products three to eight times (Amey, 1987). This fermentation process is also very popular in other parts of East Africa as Tanzania, Rwanda, and Democratic republic of Congo (Hahn, 1989).
Cassava fermented food in Central Africa
Chikwangue or cassava bread

M-bong is eating with meats, fish, groundnuts, green leaves(Balagopalan, 2002b). Cassava roots used for meduame-mbong preparation are, washed and cut into large pieces. The cutted roots are then boiled for 30 min to a 1 h. After discarding the water, cassava roots are again cut into small pieces and soaked in running water for 12 hours up to 36 hours(Oyewole, 1997; Raheem and Chukwuma, 2001; Balagopalan, 2002b; Oyewole and Asagbra, 2003; Enitan, 2010; Bull, 2011).

Chickwangue or cassava bread ―bâton de manioc‖ is the most popular cassava processed food in Democratic Republic of Congo. It is also prepare and appreciate in many central African countries such as Cameroon, Gabon, Congo Brazaville, Central African Republic…The alternative names of chikwangue in the others communities are Ntuka, bugali, kmonmogo, chawada, bobolo, myondo, mboung, mangbele (Oyewole and Yemisi, 2003). The cassava roots are peeled and the rind is removed. Cassava roots are then soaking in water and left for three days up to two weeks to ferment until they become ssoft (Balagopalan, 2002b)to ferment until they become soft. The fibers are removed from the pulp, which are heaped on a rack for further fermentation or covered with leaves and pressed using heavy objects to drain off excess liquid. The pulp is then ground and sieved to produce flavor and pounded in a mortar. The fine pulp is steamed in pots. Chickwanghe is a very viscous paste, much thicker than fufu and appreciate in several countries(Nwankwo et al., 1989; Oyewole Olusola and Yemisi, 2003)
Fermented boiled roots or Meduame-Mbong
Meduame-m-bong or fermented boiled cassava roots is a cassava fermented based food originate from Cameroon. Meduame-

Fufu
Fufuis a food made from soaked fermented cassava. Fufu is a popular cassava food found in several African countries. The alternative names of fufu are foufou, foofoo, fulful, foutou, akpu, udep utim, farine, yakayeke, agbalima, water-fufu, according to Oyewole and Yemis, 2003. Fufu is traditionally produced and marketed as a wet, pasty food product. For the production of fufu, the preliminary operations units are similar to the gari one Cassava roots are then peeled, washed, cut into thick chunks of 20 cm long, and soaked in water contained in earthen ware pots or in a slow flowing stream. The fermentation takes about four to five days. During this period, the cassava roots ferment and soften, releasing HCN into the soak water. A characteristic flavor of retted cassava meal also is produced. The retted roots are disintegrated in clean water, sieved, and the starchy particles that go through the sieve are allowed to settle for about 3 to 4 hours. The water is decanted while the sediment is packed into a cloth bag, tied, squeezed, and subjected to heavy pressure to expel excess water. The resulting meal is rolled into balls and cooked in boiling water for about 30 to 40 minutes. The cooked mass is pounded in a mortar with a pestle to produce a paste, fufu that can be eaten with sauce, soups, or

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stew. Fufu is also sold to consumers in wet form in small units packaged in plastic or polypropylene bags or in ready to eat cooked form. The balls are boiled in water and the soft dough is produced (Lancaster et al., 1982; Odunfa and Oyewole, 1998; Hahn, 1992; Bamidele et al., 2015).
Cassava fermented roots or cossette
Cossette are dried cassava fermented roots. It increases cassava post-harvest conservation. Cossette are one of the most popular cassava by products in Democratic Republic of Congo. Cossette are prepare by soaking or immersing wole or peeled fresh cassava (mainly the bitter one) in a stream or stationary water. The cassava roots are soaked for three up to six days. This operation unit also help to eliminate the toxic glycoside in bitter varieties. The fermented roots are then taken out, peeled and sundried. Depending on the weather, sun-drying takes two to five days. The dried cassava roots are called cossette, which are pounded and milled to yield fermented cassava flour (Lancaster et al., 1982; Hahn, 1989; Bamidele et al., 2015). This cossette also ground into flour to be used for the manufacture of secondary products, such as donuts and cake, obtained by frying a dough made with flour mixed with wheat flour.
Cassava fermented food in West Africa
Gari
Gariis a partially gelatinized (by toasting), free-flowing granular flour with a slightly fermented flavor and sour taste. Gari is now produces and consumes in West Africa, central Africa and east Africa. In West Africa, it is the most consumed and traded of all food products made from cassava roots. It is consumed either soaked in cold water or stirred in boiling water to make a

stiff paste and consumed with choice soup. Garican be yellow (if fortified with red palm oil) or white, although gari from biofortified cassava is gaining popularity now. Seventy percent of cassava processed as human food is gari (Oduro et al., 2000; Moslehi-Jenabian et al., 2010). Its wide consumption is attributed to its relatively long shelf life and its easy preparation as a meal. There are variations in the gari produced within the sub-region in terms of physical, chemical and sensory qualities. However, the processing method used in this manual captures all variations as much as possible. It also emphasizes precautions on unit operations that have implications on finished product quality and safety (Olaoye et al., 2015; Adeniran and Ajifolokun, 2015; Zhu et al., 2015).
Attiéké
Attiéké is an essentially flavour starchy food, produced from fermented cassava root, originally prepared and consumed exclusively by some ethnic groups from Côte d‘Ivoire. Nowadays attiéké is consumed in many neighboring countries such as Burkina Faso, Béni, Togo, Mali, Senegal(Assanvo et al., 2006; Djeni et al., 2011; Djéni et al., 2014; Flibert et al., 2016; Coulin et al., 2006). It is a steamed granular cassava (Oluwole et al.; Oyewole and Asagbra, 2003) meal ready-to-eat, couscouslike product, with slightly sour taste and whitish colour (Coulin et al., 2006; ZannouTchoko et al., 2011). Attiéké is similar to akeyke, a Ghaneen cassava fermented food but has a slightly sour taste and is eaten with milk or meat or vegetables. To produce attiéké, cassava roots are peeled, cut in pieces, washed and grated. During grating the cassava mass is mixed with about 10% of a traditionally prepared inoculum and about 0.1% palm oil. The inoculum is prepared by storing boiled cassava roots for

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three days in an unwashed jute bag previously used for inoculums preparation. The inoculated pulp is fermented overnight in covered bins. The fermentation softens the cassava mash and gives to this meals it characteristic flavour and texture (Firmin, 1995). After fermentation, the pulp is filled into bags and pressed for several hours. The pressed pulp is taken from the bags and squeezed through a sieve to obtain granules that are sundried and then cleaned to remove fibers and waste. The dried granules are steamed to produce attiéké, which is sold in small plastic bags as a ready-to-eat food. There is a difference in process then in the final product characteristic according to communities who produce it.
Placali is a cassava fermented food typically originates from Côte d‘Ivoire. Placali is always consumed with sauc included generally both sources of protein ( animal and vegetable). Fermented cassava flour are energizing food due certainly to its high carbohydrate content. Placaliis prepared from fermented cassava dough. Cassava roots are first peeled and washed. And, the pulp is shredded and fermented. The obtained cassava dough is crushed, diluted, screened and poured gradually into a pot containing hot water. Under the effect of the heat produced by the fire, starch gelatinizes. It becomes sticky and then solidifies. A spatula is usually used to knead the cassava paste to get placali, a brittle cassava paste(Yao et al., 2015; Onzo et al., 2015; Kouamé et al., 2015).
Lafun and efubo
Lafun is another cassava popular fermented food in West Africa (Nigeria, Benin, Togo, Côte d‘Ivoire). The alternative names of lafun are bombo, makessa, luku, nshima,

exidzi, kanyanga, mapanga and maphumu, according to (Oyewole Olusola and Yemisi, 2003). Lafun is prepared by soaking cassava roots for three days. The roots are grated and allowed to sun dry. The product is then grounded into a very fine powder form. An estimated amount of boiling water is mixed into an estimated amount of lafun flour. It is allowed to cook and turned constantly to prevent any lump formation and burning. Another cassava fermented flour similar to fufu is efubo. It is a cassava fermented dry flour commonly consumed in the western states of Nigeria(Uzogara et al., 1990). 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 three to four 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 ‗efubo‘(Uzogara et al., 1990). Kuboye and Ogunjobi (2016) put out another method of lafun production. It is involves soaking of cassava roots to ferment after which they are peeled, dewatered, sundried, milled and sieved to yield lafun(Wakil and Benjamin, 2015; Kuboye and Ogunjobi, 2016).
Kokondé
Kokondé is also known as Kokonte, Crueira or Alebo(Oyewole Olusola and Yemisi, 2003). It is an Ivorian originatescassava fermented food. Kokondé is prepared with fermented cassava ships. Then, cassava roots are first processed into fermented chips by peeling and soaked for hours. After grinding (optional), the pieces are washed and dried in the sun. Thatched roofs or sheet metal are used for drying. Drying may take several weeks depending on the state of the sunshine. The obtained fermented chips are crushed, ground and sieved into flour. The flour is cooked in a shooting paste. Kokondé

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is consumed with a sauce(Quintson, 2015; Jensen et al., 2015).
Agbelima
Agbelima is a popular cassava fermented food in Ghana and Côte d‘Ivoire. It also used as raw material in the preparation of a wide range of traditional cassava meals including banku, akple and kenkey and can easily be produced in larger quantities at a relatively low cost (Ellis et al., 1997). The production ofagbelima involves the use of atraditional inoculum, the kudeme. According to (Ellis et al., 1997; Nwankwo et al.)the main purpose for using this inoculum is for souring and improving the texture, color and flavor of the product. The cassava roots used for agbelima production are knife peeled and steeped in water for initial fermentation and then ground to paste(Amoa-Awua etal., 1996; Dziedzoave et al., 2000). The grated mash from obtained is inoculated with a proportional quantity of kudeme. The cassava paste is left to ferment for up to 2 days in polypropylene sackswithout the application of any external pressure on the sacks. The paste is then pressed. And the paste is removed from the sacks, crumbled or granulated, and then steamed(Rosales-Soto et al., 2016).
Loi-loi
Loi-loiis a kind of fufu which is popular among the Riverine States of Nigeria, especially Rivers, Cross River and Akwa Ibom States(Ray and Sivakumar, 2009). The processing varies but basically consists of hanging the product at the prevailing tropical climate as conditioning prior to preparation for final consumption or spreading in a thick heap to dry for one to five days. Fermentation takes place resulting in the development of a characteristic aroma. The preparation is thus: cassava roots are peeled, washed, and soaked for two

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 a 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 is formed to produce prepared loiloi(Uzogara et al., 1990).
Attoupkou
Attoupkou is a popular food in the southeast of Côte d‘Ivoire(Nevry et al., 2007; Yao et al., 2015). The cassava roots are first peeled and cut coarsely. The fibers are removed and then the tubers are washed and shredded to give cassava dough. The cassava dough obtained is fermented and drained during a night under stone bloks pressure. The fermented dough is sifted and dewatered using sieve to eliminate some of the fibers. A steaming in a steamer gives a sticky cake, the attoupkou which is then packaged(SoroYao et al., 2013)
Dumby
Dumby is a common traditional food in Liberia. The cassava‘s skin, coarse central fibers, and rind are removed and the boiled tubers are placed in a wooden mortar and beaten with a heavy pestle. As the mass becomes homogenous, the pestle produces a loud crack as it gets thicker. Dumby is normally eaten witha soup made from a variety of meat and vegetables(Raheem and Chukwuma, 2001). In Liberia, cassava is made into dumby, which is prepared by placing boiled cassava roots following pounding, the dumby is cut into pieces and put in soup supplemented with vegetables. The food is used to feed children because of its high protein content(Balagopalan, 2002b).

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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 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(Uzogara et al., 1990; Iwuoha and Eke, 1996). An alternative handling for long term storage is to dry the chips under the sun for several days(Balagopalan, 2002a).
Kapok pogari
Kapok pogari is a mid-western Nigerian food is similar to gariin preparation. The only difference is that the grated and fermented mass is not sieved before roasting. The resultant product has bigger particles. Kapok pogariis consumed with fish, coconut or meat (Balagopalan, 2002a; Soro-Yao et al., 2013).
Bêdêkouma
Bêdêkouman is a cassava fermented food family located in Côte d‘Ivoire. It production is mainly located among Aboure N'zima ethnic group in the Southeast part of the country. It is a white bread as food with 10 to 15cm as size packeted in Tomatococcus danielli leaves localy called ―attiéké leaves‖(Aboua, 1988). Bêdêkouman can be stored at room temperature for 4 days (Koffi-Nevry et al., 2005). To produce bêdêkouman the fermented cassava mash is cooked, shelled and shaped into Tomatococcus danielli. It is eaten with vegetables, fish or meat.

Microorganisms associates with cassava fermented food in Africa
Several microorganisms are involved in cassava fermented foods fermentation. It include lactic acid bacteria, Bacillus strains, yeasts, moulds and some others organisms. The main microorganisms associates in cassava food fermentation are as shown in table I.
Biochemical compound produce during cassava food fermentation
Volatiles organic compounds
The change in aroma as volatiles and flavour compounds found in African cassava fermented based food includethese molecules (Carvacrol (McFeeters, 2004; Damasceno etal., 2003; Schwan et al., 2014; Corral et al., 2015; Morales et al., 2003; Muyanja et al., 2012; Onyango et al., 2004; Dhellot et al., 2014; Djeni et al., 2015; Lasekan et al., 2016):
Aldehydes: Propanal , 2-Methylpropanal, Butanal , 3-Methylbutanal, 2-Methybutanal, Pentanal, 2-Pentenal, Hexanal, 2-Hexenal, Heptanal, 2,4-Hexadienal, 2-Heptenal, Benzaldehyde, Octanal, 2,4-Heptadienal, Furfuryl, 1,3 butanediol,Ethyl acetate, Isobutyl acetate, Phenylethyl acetate, Benzene acetaldehyde, 2-Octenal, 2acetylpyrroline, Nonanal, 2-Nonenal , 2,4Nonadienal, (2Z)-2-phenyl-2-butenal, 2,4Decadienal; Alcohol: 1-Butanol, (isoamilic alcohol), 2-methyl 1 butanol, Phenylethanol, Ethanol, 3-Methyl-1-butanol, 1-Pentanol, 1Hexanol;
Alkanes: Pentane, Hexane, Heptane, Octane, 2-Octene , Decane , Dodecane , Tridecane, Tetradecane;
Ketones: Acetone, 2,3-Butanedione, 2-

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Butanone, 3-Methyl-2-butanone, 2Pentanone, 2,3-Pentanedione, 3-Hydroxy-2butanone, 2-Heptanone , 3-Octen-2-one , 1octen-3-one, 2-Nonanone, L-carvone, Undecanone, Mrthyl nonylcetone, Piperitone, L-carvone, Iso-menthone, Menthone;
Nitrogen compounds: Pyridine, 2Ethylpyridine, 2,5-Dimethylpyrazine , Trimethylpirazine , Tetramethylpyrazine , 1Piperidinecarboxaldehyde Ethyl 3pyridinecarboxylate; Terpenes, α-Terpeniol, β-Citronellol, Guaiacol, 1-3 Butanodiol ; Others : Myrcene, Limonene, eucalyptol, para-cymene, beta ocimene, β beta ocimene, Gamma terpinene, 2,Terpinen-4-ol, Methyl salicylate, Estragol, Methyl thymol ether, Lcarvone, , Citronnellyl formiate .
Organic acids
The microorganisms involved in cassava fermentation have homolactic and heterolactic activities. The process of organic acids production necessitates the initial breakdown of starch to sugars before these sugars are fermented by both moulds, lactic bacteria.

There are therefore crucial for the cellular

replication and growth. Plants, yeast and

some bacterial species in fermented food

contain the folate biosynthesis pathway and

produce natural folates. But mammals lack

the ability to synthesize folate and they are

therefore dependent on sufficient intake

from diet(Gregory, 1989; Patring et al.,

2005; Moslehi-Jenabian et al., 2010).

Several lactic acid bacteria and yeast have

been identified to synthetize folates (vitamin

B9) in different medium. Among them,

some have been isolate in cassava fermented

by products. It is the case of Lactobacillus

rhamnosus, Lactobacillus plantarum,

Lactobacillus acidophilus, Lactobacillus

reuteri, E. faecium, Lactobacillus

fermentum,

Lactobacillus

brevis,

Lactobacillus salivaris, S. cerevisiae

(LeBlanc et al., 2007; Chelule et al., 2010;

Hasan et al., 2014; Anyogu et al., 2014).The

proper selection of probiotic folate

producing strains provides is then a strategy

for the development of novel functional

cassava fermented foods with increased

nutritional value(Gregory, 1989).

Role and function of fermentation on cassava food

The main organic acid synthetize by bacteria during cassava fermentation are butyric acid, Hexanoic acid, Octanoic acid, Decanoic acid, Nonanoic acid, Dehydro acetic acid, 2Methyl propanoic, Oxalic, Citric, Tartaric, Mallic, Ascorbic, Lactic, Acetic, Fumaric, Propionic, Carboxylic acids, Hexanoic, Octanoic, Nonanoic (McFeeters, 2004; Damasceno etal., 2003; Schwan et al., 2014; Corral et al., 2015; Morales et al., 2003; Muyanja et al., 2012; Onyango et al., 2004; Dhellot et al., 2014; Djeni et al., 2015; Lasekan et al., 2016).
Vitamins
Folates or vitamin B9 are the essential cofactors in the biosynthesis of nucleotides.

Fermentation is a metabolic process converting carbohydrates to organics acids. It is a food technology used some centuries. It is appreciate for it many advantages in food science. Fermentation can increase protein and vitamins content and improve the balance of essential amino acids. Fermentation increase also the volatiles organic content and reduce anti-nutrients content.
Aroma and flavor change
Fermentation makes the cassava fermented food palatable by enhancing its aroma and flavor. These organoleptic properties make

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fermented food more popular than the unfermented one in terms of consumer acceptance. Furthermore, food acidification does not result in improvement of food texture and quality(Chelule et al., 2010). Then, fermentation is unique in that it modifies the unfermented food in diverse ways, resulting in new sensory properties in the fermented product. However, not all bacteria and moulds are beneficial in enhancing food flavor. The aroma and flavour compound found in African cassava fermented based food include aldehydes; organic acids, alcohol, alkanes, terpenes, ketones, nitrogen compounds, and some others compound(McFeeters, 2004; Damasceno et al., 2003; Schwan et al., 2014; Corral et al., 2015; Morales et al., 2003; Muyanja et al., 2012; Onyango et al., 2004; Dhellot et al., 2014; Djeni et al., 2015; Lasekan et al., 2016). The aroma and flavor compound depend on the involved microorganisms in the fermentation. In some instances, they may cause food spoilage since their enzymes may lead to generation of fermentation digests that have offensive odours or flavours, making food to be entirely unpalatable
Physical and biological properties
Many operation units of the fermentation procedures involve steeping tubers in water for long periods. In a number of cases, the dry matter had decreased. The decrease can attribute to a partly reduction in sugar and starch and the leaking of soluble constituents. In addition, the softening of the tubers may be leading to increased absorption of water, contributing to the reduction in dry weight. During the soaking of roots in cassava food production, the texture of the roots undergoes noticeable change and the roots are rendered soft. The fibers content in the fermenting tubers rose with the time of fermentation and the effect

is uniform with all varities of cassava. Fibers

content increase is due to the action of

pectinolytic and cellulolytic enzymes

produced

by

the

fermenting

microorganisms, which break down cell

membranes (Aloys and Angeline, 2009;

Aloys and Hui Ming, 2006; Aloys and Zhou,

2006b).

Cassava fermented food preservation

The preservative activity of lactic acid bacteria and others associate microorganisms in some cassava fermented product in one of the main reason of it fermentation. It is a alternative issue for cassava food storage in poor communities in African countries. During cassava fermentation process, some biochemical compound like organic acids, aldehydes, alcohol, hydrogen peroxide, carbon dioxide are produce(Schwan . et al., 2014; Corral . et al., 2015; Lasekan et al., 2016). The antagonism of lactic acid bacteria against pathogenic or other bacteria is believed to result from the action of the acids on the bacterial cytoplasmic membrane which interferes with the maintenance of membrane potential and inhibits active transport and may be mediated both by dissociated and undissociated acid (Cherrington et al., 1991). The antimicrobial activity of each of them is not correlate with it molar concentration. It can inhibit yeasts, moulds and bacteria (Blom and Mørtvedt, 1991). Propionic acid inhibits fungi and bacteria. The contribution of aldehyde to flavour is more than it bio preservative properties. Hydrogen peroxide accumulate can be inhibitory to some microorganisms (Condon, 1987). This inhibition is mediated through the strong oxidising effect on membrane lipids and cell proteins (Castberg and Morris, 1976). Carbon dioxide, formed during heterolactic fermentation, can directly create an anaerobic environment

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African cassava Traditional Fermented Food: The Microorganism