The roots are peeled, washed, cut into pieces and then submerged in water in earthenware pots at room temperature for 5 days. During this period, the cassava roots ferment and soften, releasing hydrogen cyanide into the soaking water, reducing pH levels and imparting the characteristic flavour of the retted cassava meal. The mash is sieved through small baskets to remove the ligneous central strands. The solid residue is pressed to drain off the water and formed into small balls. The fufu is 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 a soft dough is produced (Uzogara et al., 1990). Assessment of fufu was carried out in two different fermentative processes and compared with that of the traditional product. In one process, fufu was produced involving the steeping of cassava tubers for 48 h followed by grating and fermenting for another 48 h, whereas another technique involved grating cassava tubers, dewatering/fermentation for 24 h before re-steeping for another 48 h.
The dominant group of microflora were lactic acid bacteria, Bacillus sp. and yeasts. The microflora was more diverse and with higher counts in the traditional product after 24 h. Initial counts were 8.88 log cfu/g, whereas the respective counts in samples after soaking and grating were 6.32 and 8.55, respectively. It then increased to 9.24 log cfu/g after 48 h fermentation. The pH decreased from 6.8–4.3 in the traditional process and from 6.6 to 4.2 in the modified process. The titratable acidity increased from 0.36-4.0 % (w/w lactic acid) in the traditional product and from 0.24-1.0 %, respectively, in the modified process. Grated mash fermentation reduced the cyanogenic glycosides content by 85.5 % in 72 h compared with 79.5 % in the traditional fermented product. Odour and flavour ratings were significantly higher (p < 0.05) for the modified process. There was no difference in colour or texture due to the processing method. Fermentation of grated cassava produces a product with a better acceptable product (Achi and Akomas, 2006). In another study, cassava mosaic resistant cultivars were processed for the production of fufu. The product had the proximate compositions, moisture (7.31-8.40 %), which were within the recommended standard for edible cassava flour, protein ranged from 0.35-2.45 %, ash (0.15-1.50 %), fat (0.12-0.61 %), fibre (0.01-0.20 %), carbohydrate (81.81–90.37 %) and dry matter (81.7-92.69 %). Sensory evaluation of dough prepared from the cassava fufu flours showed that colour, odour, elastic quality, hand feel/texture and overall acceptability were all acceptable to the panellists (Hussein et al, 2012).
Fufu is also called as akpu and Loi-loi in some parts of Nigeria. A fibrous by-product obtained during fufu production is sold as animal feed, either in its wet form or after sun drying (Obadina et al., 2008). Species of Lactobacillus, Leuconostoc and
Streptococcus (all lactic acid bacteria (LAB)) are the predominant microorganisms in fufu along with Bacillus subtilis, Klebsiella and Candida krusei (Blanshard et al., 1994, Brauman et al., 1996, Oyewole, 2001, Oyedeji et al., 2013). Production of gari and fufu has been scaled up in Nigeria (Ezedinma, 2006).
5.2.3.3 Lafun
Lafun is a fine powdery cassava product that is prepared by fermentation and is commonly consumed in the south-western states of Nigeria. The traditional method of processing cassava into lafun reduces toxic cyanogenic compounds and also imparts a strong smell to the product (Cereda and Mattos, 1996). The whole or peeled roots are immersed in a stream, in stationary water, or in an earthenware vessel for 3–4 days and fermented until they become soft. The fermented roots are then taken out and the pulp broken into small crumbs and sun-dried on mats, racks and house roofs. The dried crumbs are milled into flour. The flour is added into boiling water with constant stirring until a smooth thick paste is formed. The paste is cooled to about 35 °C and is then served with soup (Uzogara et al., 1990). The fermented and dried cassava pulp, lafun, is similar to cossettes in Zaire and Rwanda, kanyanga and mapanga in Malawi and makopa in Tanzania. Microorganisms involved in lafun preparation include species of Bacillus, Klebsiella, Leuconostoc, Corynebacterium, Candida and Lactobacillus (Treche and Massamba, 1995).
A study was conducted by Padonou et al. (2009), which demonstrated the quality of two types of lafun (Chigan lafun and ordinary lafun) produced in Benin of Nigeria. The distinctive characteristics of Chigan lafun (the preferred type) were its lower solubility and fibre content and its higher hot paste viscosities compared to ordinary lafun. Both the types, Chigan lafun and ordinary lafun, were the dried and the white product with variable pH range (4.5–8.8), rich in carbohydrates (76.0 % of starch and 3.3 % of crude fibre), but poor in protein content (1.0 %) and contained fat (0.4 %) and ash (1.2 %). The products contained fat and ash content to the proportion of 0.4 % and 1.2 % respectively. The swelling power of the lafun flour (expressed by the quantity of water absorbed by 1 g of flour) was 28.9 g water/g for the both types. It has been observed that moulds such as Aspergillus spp., Fusarium spp., Mucor spp. and Rhizopus spp. could develop in lafun after several days’ exposure to ambient conditions (Obadina et al., 2009). Microbiological assessment of different lafun samples collected from the Ogun and Oyo states of Nigeria showed that the spoilage of the fermented product mainly occurs due to the presence of A. niger, which ranged between 4.6 × 105 to 8.1 × 105 cfu/mL (Oyetoro etal, 2013). Lafun pastes with little or no odour, having a characteristic white colour and good texture, were preferred by consumers (Oyewole and Afolami, 2001). Cassava-fermented products similar to lafun are consumed in Angola, where it is known as Bombo or makessa; in Zaire, where it is called Luku or cossettes; in Zambia, where it is called Nshima; in Ghana, where it is known as Ezidzi; and in Malawi, where it is called Makaka, Kanyanga, Mapanga or Maphumu (Sanni et al., 2003).
5.2.3.4 Chickwanghe (Kwanga)
Chickwanghe is the most popular processed food form of cassava in Zaire. Myondo and bobolo in Cameroon, mboung in Gabon and mangbele in Central African Republic also belong to this group. Cassava roots are peeled, steeped in water and left for 3–5 days to ferment until they become soft. Fibres 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 on a stone, or pounded in a mortar. The fine pulp is steamed in pots. Chickwanghe is a very viscous paste, much thicker than fufu (Nwankwo et al., 1989). Traditional retting of cassava roots in ponds and backwaters (the medium is slightly acidic (pH, 5–6) and the pressure of dissolved oxygen is very low (pO2,1.96)) is very useful as it facilitates rapid softening of cassava roots and allows to shorten the fermentation duration by at least one day. In addition, the peeled roots after retting contain less tannin than the unpeeled roots and allow to obtain the alimentary products, fufu and kwanga, which have a higher whiteness (Mokemiabeka et al, 2011).