The Cassava Transformation: Africa's Best-Kept Secret

Chapter 8. The Preparation of Five cassava Products (includes images)

The Preparation of Five cassava Products Introduction CHAPTER B Both cassava leaves and roots are prepared as food by different methods in different places in Africa. Simple preparation methods have evolved over time to eliminate cyanogens from cassava roots and leaves in order to make them safe for consumption. These methods are also effective in removing water from cassava roots, which, in turn, extends the shelf-life of cassava and reduces transportation and marketing costs. There are five common groups of cassava products: fresh roots, dried roots, pasty products, granulated products, and cassava leaves.! This chapter examines the evolution of the five cassava products and shows that the traditional methods have been influenced by the availability of water and sunlight, by wage rates, and by market demand in cases where cassava is produced as a cash crop for urban consumption. This chapter also shows that there is regional variation in cassava preparation methods in Africa and that a major challenge is to diffuse the best practices from one region to another within Africa. 115 The Cassava Transformation Fresh Cassava Roots The roots of sweet cassava varieties are eaten raw, roasted in an open fire, or boiled in water or oil.2 The cyanogens in the roots are destroyed by slowly cooking the roots. Starting with cold water, the roots_ are gradually heated, promoting the hydrolysis of the cyanogens (Grace 1977). Boiled cassava roots may be pounded alone or in combination with other starchy staples such as banana (or plantain), yam, cocoyam, or sweet potato. Fresh cassava roots, boiled in water or in oil, are commonly sold by food vendors in major cities and consumed by workers as snacks or for lunch.3 Pounded cassava is made from roots boiled in water. The preparation of pounded cassava is elaborate and cumbersome because the boiled cassava roots get sticky during pounding. In Ghana, it takes two women to pound a mortar of boiled cassava roots; one person in a standing position , pounding with a pestle, and the second in a sitting position, removing the sticky dough from the pestle by hand. Dried Cassava Roots Dried cassava roots are stored or marketed as chips, balls, or flour. Chips and balls are milled into flour at home by pounding with a mortar and pestle in preparation for a meal. There are two broad types of dried cassava roots: fermented and unfermented. Sun- or smoke-drying of unfermented dried cassava roots is the simplest method of cassava preparation (fig. 8.1). Smoke-drying requires a large amount of fuel wood. Since this method is inefficient in the elimination of cyanogens, it is used mostly for preparing sweet cassava varieties, which have a low cyanogen content. In the case of fermented dried cassava roots, the fermentation is accomplished in one of two ways: stacking in heaps or soaking in water. To prepare roots fermented by stacking in heaps, the cassava is cut into pieces, peeled, washed, and left in the sun for a day. The roots are then stacked in a heap, covered with leaves, and left to ferment for about one week. Fermentation in heaps has the advantage of improving the nutritional value of 116 ..., Major processing steps Peeling Splitting Crushing Water expressing Fermenting Sieving Drying Cooking End-product at point of entry into marketing system Cassava roots Fermented I C~ked Unc~ked I T T IPaste Dried Roots Rgure 8.1. Traditional Cassava Processing and Food Preparation Methods. Source: COSCA Study. Granules Key +C:J-. Joint steps o Labor use intensive o Firewood use intensive -r:Q> Labor and firewood use intensive L 7 Water use intensive o Sunlight use intensive """i ". (1) 11 .., (1) " II> .., III o ' " o ~ . . . .III <: III 11 .., o 0.. c: " . . The Cassava Transformation the product. Most of the nutrients that are lost by soaking are retained when fennentation is done by heaping. Additionally, mold growth on the cassava roots in heaps promotes fennentation and increases the protein content of the dried cassava roots (Tanzania Food and Nutrition Cecter and International Child Health Unit n.d.). The recent introduction of the grater has eliminated stacking and fermentation and therefore has saved time. The roots are now simply peeled, washed, and grated.4 The pulp is placed in a perforated container and covered , and a weight is put on it for about three hours. The cyanogens are squeezed out along with the effluent. The half-dried pulp is then dried in the sun (Alyanak 1997). A common fennentation technique is to soak the fresh roots in a puddle or in a pot of water for three to five days. The roots are then peeled (if not peeled prior to soaking) and sun- or smoke-dried direcdy as whole roots. Alternatively, they can be crushed and pressed to remove the water and molded into balls. The fennentation process, whether in water or in heaps, influences the taste of the final product. The longer the fennentation period, the stronger the sour taste. Taste is an important attribute, especially for consumers who eat fennented cassava products and who desire a strong sour taste. The cassava product needs to be visually attractive to a buyer. Bright color is a desired attribute.5 The brightness of the color of dried roots depends on the method and duration of the fennentation, on the method of drying, on the efficiency of the drying energy, and on the cleanliness of the drying environment. Cassava can be sun-dried on virtually any surface in the open air, such as a large flat rock in the field, the shoulders of a paved road, flat rooftops, a flat basket, or even bare ground. Although roots dried in a basket may be moved in case of a bad weather, roots being dried on a rock, on the roadside, or on a rooftop often are not easily moved. If it rains, the cassava is soaked, and drying starts allover again. The wide range of drying surfaces used is such that the product can gather significant amounts of mold, dust, and other dirt, which influence the color of the product. In 118 The Preparation of Five Cassava Products Table B.1. Type of Cassava Food Products in the Congo, Cote d'ivoire, Ghana, Nigeria, Tanzania, and Uganda. Sourr;e: COSCA Study. CASSAVA FOOD PRODUCTS CONGO COTE D'IVOIRE GHANA NIGERIA TANZANIA UGANDA Dried roots 70 8 27 48 91 21 Granulated products 0 45 43 39 0 0 Pasty products 25 8 7 13 0 0 Fresh roots 5 37 23 0 6 76 Others 0 2 0 0 3 3 TOTAL 100 100 100 100 100 100 the humid climates, such as in the forest zone, where it rains frequently and where sun-drying is inefficient, the color of the flour is dull white. The savanna zone has a comparative advantage in preparing dried cassava roots because sun-drying is more efficient. Smoke-drying is done on racks over the kitchen fire. This process imparts a dull color to the product. Processors usually scrape off the dark coating of smoke before it is milled into flour. The drying process reduces the bulk of the cassava roots, extends shelf life, and thus facilitates cassava marketing in urban areas. Cassava farmers remote from market centers have a comparative advantage in preparing dried cassava roots because dried roots are cheaper to transport to distant urban markets than fresh roots. Dried cassava roots are common in the Congo because of poor roads and limited access to urban markets. When properly dried, cassava roots will keep for several months if they are stored over the kitchen fire; otherwise they may be attacked by weevils or become moldy. Dried cassava roots are common in Tanzania because cassava is used as a famine-reserve crop (table 8.1). Cassava is eaten in the form of dried roots more often in rural than in urban areas (Idowu 1998). The traditional method of converting dried roots into cassava flour is to pound them in a mortar with a pestle and then sieve the flour through a fine basket or a perforated metal bowl. Consumers can purchase dried cassava roots already milled into flour. Yet cooking the dried root flour is painstaking because it involves stirring the flour in boiling water until it turns into a thick paste. 119 The Cassava Transformation The level of each resource-i.e., sunlight, fuel wood, water, or laborneeded to prepare dried cassava roots varies with the preparation method used. Sun-drying of cassava roots is sunlight-intensive, while smokedrying requires fuel wood. Because of the abundance of sunlight, farmers in the savanna usually adopt sun-drying methods, while farmers in the forest zone adopt the smoke-drying method because of limited sunshine. Farmers in the savanna ferment cassava roots by stacking, while farmers in the forest zone ferment by soaking because of the availability of water. Peeling is more labor intensive when it is done prior to rather than after soaking. Milling by pounding with mortar and pesde is always labor intensive. In most places, women provide the labor used to prepare dried roots. COSCA researchers interviewed a woman in the Congo who was pounding dried cassava roots to make flour for the family dinner. Her husband was sitting under the shed of palm leaves with muddy feet and muddy digging hoe beside him, signs that he was resting after plowing in the field. The COSCA researchers asked the woman why she did not take the dried cassava roots to the nearby mission station to be milled by a machine. Before the woman could respond the man said, "I would not eat cassava flour milled by machine."6 Pasty Cassava Products lWo forms of pasty cassava products are common in Africa. The most popular is called "uncooked paste" because it is stored or marketed without cooking. To prepare the uncooked paste, the roots are soaked in water for three to five days, during which time the roots soften and ferment. The soaked roots are then manually crushed in a fine basket or in a perforated metal bowl in a sack submerged in water. As the soft root is crushed, it is sieved by shaking, thereby separating the pulp into the sack while keeping the fiber in the basket. The sack of pulp is squeezed, often manually or sometimes under a heavy weight, to express the effluent. The end product is a dense pulp, which is stored or marketed. 120 The Preparation of Five Cassava Products Preparing uncooked paste is water-use intensive, as additional water is needed, after the soaking, for sieving. Therefore, the preparation of cassava as uncooked paste is concentrated in areas with an abundant water supply. The sieving in water is labor-intensive. In most places women provide the labor to prepare the uncooked paste. This is an unpleasant chore. Women stand in a puddle of water for hours, shaking baskets of the fermented cassava. Preparing cassava as an uncooked paste extends the shelf life of the cassava product and reduces its volume in comparison with fresh roots. Yet the uncooked paste is not a convenient food product because it needs to be cooked and pounded, sometimes twice, before it is ready for a meal. However, it is commonly used to feed hired labor employed in cassava production. The uncooked paste is less expensive than other cassava products while at the same time it gives a feeling of satiety because it is heavy. In a COSCA study village in southwestern Nigeria, the uncooked paste was nicknamed "six-to-six" by the farmers, meaning 6:00 A.M. to 6:00 P.M. because hired farm labor eat it twice each day, once in the morning and once in the evening, with nothing in between. In some parts of Nigeria, the uncooked cassava paste is transported over long distances in truckloads and retailed in urban markets in small plastic or polypropylene bags. Cooked cassava pasty products recently have been introduced in Nigerian urban markets. Every evening in major cities in the cassavagrowing areas of Nigeria, it is common to find women selling cooked cassava paste wrapped in plastic bags. As women go home from work or from market, they stop and buy some for the evening meal. The paste is best eaten when it is hot. A housewife may buy it in bulk and warm it when it is time to eat. When it is warmed, however, the product forms a jelly on the surface and pounding is required to restore a uniform texture. Although more research is needed on preparation methods, cooked cassava paste is a promising food for busy urban consumers. Cassava paste can also be stored or marketed in a steamed form. To prepare the paste, fiber is removed by hand from roots fermented by 121 The Cassava Transformation soaking them in water. The roots are then stacked in a heap to further ferment while covered with leaves and pressed with heavy objects to express water. The pulp is ground with a stone or pounded in a mortar. The resulting fine pulp is firmly wrapped in leaves and steamed. There are several variations of this method. For example, in some places the roots are peeled before soaking to improve the attractiveness of the end product. However, peeling before soaking makes the product more expensive because fresh cassava roots require more peeling labor than do roots softened by soaking . In some places, steaming is done twice. After the first steaming the product is kneaded, rewrapped, and then steamed a second time. Steamed paste is stored or marketed in a ready-to-eat form. Preparing steamed paste is expensive because many steps are involved and each one requires additional inputs. For example, grinding and sieving are labor-intensive. The soaking step is water-use intensive, and steaming is fuel wood-use intensive. In the Congo, steamed paste, chickwangue, is prepared entirely by women. It is also common throughout Central Africa, from Cameroon to Burundi (Jones 1959).7 Steamed paste is not as bulky as fresh cassava roots and therefore it is less expensive to transport. The double fermentation as well as the steaming impart a long shelf life to steamed paste. The sour flavor achieved through extended fermentation is a characteristic that is cherished by regular customers. Yet it is also a turnoff to potential new consumers. The color of the pasty products (uncooked or steamed) depends upon the quality of the water in which the cassava is soaked. Cassava may be soaked in running water, such as a stream or a river, or in stagnant water, such as a ground puddle or water in a container, depending on what is available. If cassava is soaked in clean running water, the pasty product will have a bright white color. If the soaking is done in dirty water or over an extended period, the product acquires a dull color. In the Congo, the regions of Bandundu and Bas-Congo are suppliers of steamed paste to the urban population of Kinshasa, where consumers prefer Bas-Congo products that are brighter in color. The brownish tint in cassava paste in the Bandundu region has been traced to the color of the water in the streams in which the cassava is soaked (Osiname et al. 1988). 122 The Preparation of Five Cassava Products Granulated Cassava Products There are three common types of granulated cassava products: gari, attieke, and tapioca. The methods for making granulated cassava products originated in Brazil. As we pointed out in chapter 1, the diffusion of cassava from South America to West Africa was delayed until the methods of preparing cassava as granulated products were also introduced from South America. Cari is a toasted food product that is much more common in Nigeria and Ghana than in the other four COSCA study countries. To prepare gari, fresh cassava roots are peeled, washed, and grated. The resulting pulp is put in a porous sack and weighted down with a heavy object for three to four days to express effluent from the pulp while it is fermenting. The dewatered and fermented lump of pulp is pulverized and sieved and the resulting semi-dry fine pulp is toasted in a pan. Palm oil is sometimes added during toasting in order to prevent the pulp from burning. However, the addition of palm oil changes the color of the gari from white to yellow. The grating, effluent expression, pulverization, toasting, and addition of palm oil are adequate to reduce cyanogens to a safe level (Hahn 1989). Fermentation imparts a sour taste to gari. The duration of fermentation varies depending on consumer preference for sour taste. The COSCA study found that commercial gari processors in Nigeria ferment cassava for different lengths of time, depending on the market. For example, in Edo State, a major commercial cassava-producing state, gari preparers ferment for a maximum of three days for gari prepared for markets in Eastern Nigeria and for five days or more for markets in Western Nigeria . The strong sour taste in gari acquired from extended fermentation is appreciated by the Yoruba people of Western Nigeria. The Ibo people of Eastern Nigeria prefer gari that is bland in taste. Toasting extends the shelf life so that gari easily can be transported to urban markets. If kept in a dry environment, gari will store better than grain because gari is not known to be attacked by weevils (Okigbo 1980). Cari preparation tasks are labor-intensive, and women provide the manual labor for these tasks. However, in the next chapter we shall 123 The Cassava Transformation discuss a mechanized method of cassava grating that is widely used in Nigeria and Ghana. A large amount of fuel wood is needed for the toasting . Many buy fuel wood and hire female labor to prepare gari for sale to urban consumers. To summarize, gari is a convenient product because it is stored and marketed in a ready-to-eat form. It can be soaked in hot or cold water, depending upon the type of meal being prepared. Gari has a long shelf life, and it is therefore attractive to urban consumers. It is the most common form in which cassava is sold in Ghana (Doku 1969) and in Nigeria (Ngoddy 1977). The second type of granulated cassava product is attieke, a type of steamed cassava that is found only in the C6te d1voire. Attieke is made in much the same way as gari, with more or less the same inputs. Instead of toasting, however, attieke is steamed. Attieke is available in a wet form, and it has a shorter shelf life than does gari. The third type of granulated cassava product is tapioca, which is primarily consumed in Togo and Benin.8 To prepare tapioca, cassava is grated and then put in water, pressed, and kneaded to release the starch. The starch is permitted to settle at the bottom of the container, and the water is drained off. The operation is repeated several times to prepare high-quality product. The damp starch is spread in a pan and toasted in the same way that gari is, to form a coarse granular product. It may later be sifted to sort the granules by size. Cassava Leavas Cassava leaves are edible and a more convenient food product than are fresh roots. Cassava leaves have a nutritive value similar to that of other dark green leaves and are an extremely valuable source of vitamins A (carotene) and C, iron, calcium, and protein (Latham 1979). The consumption of cassava leaves helps many Africans compensate for the lack of protein and some vitamins and minerals in the roots. Cassava leaves are prepared by leaching them in hot water, pounding them into pulp with a mortar and pestle, and then boiling them in water along with 124 The Preparation of Five Cassava Products groundnuts, fish, and oil. This process eliminates cyanogens from the leaves, making them safe for human consumption. Cassava leaves are an important vegetable in the Congo and in Tanzania . The COSCA study found that farmers in the Congo select cassava varieties with a large canopy of leaves. In Tanzania, farmers plant "tree cassava," mpiru, for the production of leaves. In countries where cassava leaves are eaten as vegetables, producers earn additional income by selling cassava leaves. Truckloads of cassava leaves, locally called pondu in the Congo, are a common sight on the roads from the provinces to Kinshasa . Cassava leaves are not eaten in Uganda because they are held in low regard. Their consumption is considered an indicator of low economic status (Otim-Nape 1995). Cassava leaves are not eaten in West Africa, except in Sierra Leone, because several indigenous plants supply vegetables traditionally consumed with yam (Okigbo 1980). Most of these vegetables are, however, available only during the rainy season. Therefore, there is a seasonal gap in the availability of vegetables in West Africa which cassava leaves could fill. For example, an assessment of the nutritional status of children in parts of the forest zone of southwest Nigeria shows that between February and May, many children are malnourished, and kwashiorkor cases are common and infant mortality is high (Nnanyelugo et al. 1992). The period from February to May is a dry period, and green vegetables are scarce, but cassava leaves are available because cassava grows leaves all year round. Women in the cassava-growing areas of West Africa are generally not aware that cassava leaves are edible and rich in protein, vitamins, and minerals. The women do not know that their children can be saved from malnutrition and even death by feeding them cassava leaves in the dry months when other vegetables are in short supply. The consumption of cassava leaves as a vegetable will make cassava production more profitable and increase the food security and nutritional status of African families. Cassava leaves can be stored in dry form, and since they have a lower water content, they are less expensive to dry than the roots. If leaf 125 The Cassava Transformation harvesting is properly scheduled, it does not have an adverse effect on cassava root yield. For example, when leaves were harvested monthly, the reduction in root yield ranged from 22 to 42 percent (Dahniya 1983). Root yields were not affected, however, when the leaves were harvested every two months (Lutaladio and Ezumah n.d.). Lessons and Challenges A lesson that emerges from this chapter is that the traditional methods used to make five cassava products have been influenced by the availability of sunlight, water, and fuel wood and by wage rates. For example, in areas where water is scarce, the sun-drying method is popular. In areas where sun-drying is not efficient, smoke-drying is practiced. Likewise, farmers who produce cassava as a cash crop process it as gari by purchasing fuel wood and hiring female labor. This diversity of natural resources and differentiation in wage rates has contributed to an array of cassava products in Africa. Another important lesson that emerges from the COSCA study is the localized nature of cassava preparation methods. For example, gari preparation is common throughout West Africa but not in Central and East Africa. The consumption of cassava leaves is common in the Congo and Tanzania but not in the Cote d'Ivoire, Ghana, Nigeria, or Uganda. The challenge is to promote the diffusion of the best practices, such as the preparation of gari and cassava leaves, throughout the cassava-growing areas of Africa. Nigeria and Tanzania provide an example of the mutual benefits of exchanging information on best practices. The Nigerian method of gari preparation could be introduced in Tanzania. Likewise, the Tanzanian best practices in the preparation of cassava leaves could be introduced in Nigeria, where cassava leaves are not now consumed. In 1994, under the aegis of the COSCA study, two Tanzanian homemakers were brought to Nigeria and paired with gari preparation host families to understudy how to make gari. The activity was interrupted by the civil strife that followed the annulment of the 1993 presidential election in Nigeria. However, we 126 The Preparation of Five Cassava Products learned subsequently that people in the villages of the two Tanzanian homemakers were mixing gari with maize to make ugali, the most common traditional maize meal in Eastern and Southern Africa (Kapinga 1995). In summary, diversity of natural resources and differentiation in usage rates have contributed to an array of cassava products in Africa. The challenge is to promote the best practices, such as the preparation of gari and cassava leaves, throughout the cassava-growing areas of Africa. 127 PHOTOGRAPHS Bundles ofcassava stems for use as planting material for sale to farmers. A field ofthe TMS cassava varieties. The leaf density reduces weed growth. Fresh cassava roots for sale in a market. Nigerian farmers harvesting cassava. Women and children peeling cassava with sharp knives in readiness for grating using mechanized graters. Mechanized grating ofcassava for a female farmer in a Nigerian village. A Ghanaian woman preparing gari by toasting grated cassava root. In Africa, women often combine cassava processing with childcare. Gari for sale along with yam (background) in Nigeria. ...