Uncultivated plants for human nutrition in Côte d'Ivoire
The importance of uncultivated plants for human nutrition in the V-Baoulé, central Côte d'Ivoire, was studied. The inhabitants of this region live at the border between the forest and the savanna. They know and use both ecosystems. The ethnobotanical, biochemical and nutritional features of 48 uncultivated plants were evaluated. Their relative importance with respect to the diet was assessed. Social and cultural factors interacting with their utilization were recorded.
Although nutrition is based on agricultural crops, uncultivated plants are an important source of vitamins and minerals, some being part of the daily diet. Leaves are prepared as vegetables mostly in times when fresh vegetables from the field are scarce. Uncultivated fruits are gathered throughout the year. They add variety and complement the children's diet particularly. Palm wines are consumed by all groups of the population. They are a valuable source of energy, vitamin C, niacin and potassium.
This paper discusses the most important plant species and the prospects of sustainable use. It also highlights the possibilities and constraints of their potential domestication. Special attention is given to the wine- and fruit-producing palm tree Borassus aethiopum, to the fruit -producing shrub Annona senegalensis, and to the annual, semi-domesticated Corchorus olitorius.
Up to now, the gathering of products from the wild has been possible without major effort. Farmers will grow these products only if there is a market demand or if, because of environmental pressures, these products become scarce. When selecting species for domestication, their possible negative image must be taken into account (`attracts snakes', `famine food').
Most of the traditional knowledge in Africa is transmitted orally. The knowledge on wild plants is in danger of getting lost as habits, value systems and the natural environment change. To preserve this knowledge, which potentially is highly valuable for future generations, it needs to be recorded systematically. We undertook this in the V-Baoulé, in central Côte d'Ivoire, in the village of Zougoussi (200 inhabitants), which lies at the border between the Guineo-Congolian rain forest and the forest-savanna transition zone. The villagers know both natural environments and practise shifting cultivation in the savanna as well as in the forest, where there is also some cash crop production (coffee, cocoa).
In addition to this ethnobotanical study, the contribution of uncultivated plants to the human diet was assessed. The nutritional importance of gathering products has repeatedly been pointed out for different regions throughout Africa. However, because of methodological problems, no quantitative assessment had previously been made.
After a brief description of the methods used, the general features of vegetables, fruits and beverages from uncultivated plants in the diet are discussed. Three selected species are then presented and conclusions are drawn for the sustainability of their use and their potential for cultivation.
Precise descriptions of the methods applied are given elsewhere (Gautier-Béguin 1992, Herzog 1992). Ethnobotanic interviews were followed by botanical and ecological descriptions of the uncultivated food plants. Their consumption was assessed by interviews recording the food intake during the 24 hours preceeding the questioning (24 hour recall), repeated monthly over one year (September 1988 to August 1989). Biochemical analyses of the foods were carried out where necessary (general composition, vitamins, minerals) and related to the recommended dietary allowance (RDA) as specified for the location (Herzog 1992).
A total of 48 undomesticated plant species are known to yield edible products; 10 of them are herbaceous plants, 12 are shrubs, 6 are lianas and 20 are trees; 16 species have parts (leaves, fruits, seeds, flowers, sprouts) that are prepared as vegetables, 31 have edible fruits and 5 are used to prepare beverages.
Nutrition is based on tubers (yams, manioc, etc.), which are prepared and consumed together with a soup or stew made from vegetables and containing, if available, some fish or meat. The food frequency for sauces or stews is represented in figure 1. There is a kind of basic recipe for sauces, which consists of tomatoes, onions, peppers, oil, salt, etc. This soup can be consumed alone (item D in fig. 1) or with other vegetables added.
Figure 1. Frequency of the consumption of different soups or stews in Zougoussi, V-Baoulé, Côte d'Ivoire in 1988-1989
|A||Abelmoschus esculentus (fresh)||H||Ricinodendron heudelotii ssp. heudelotii|
|B||Abelmoschus esculentus (dried)||I||Cucumeropsis edulis|
|C||Elaeis guineensis dura type||J||Solanum indicum ssp. distichum|
|D||`sauce claire': tomato, onion, pepper||K||Solanum americanum|
|E||Solanum melongena||L||Solanum torvum|
|F||Arachis hypogea||M||Hibiscus congestiflorus|
Fresh or dried Abelmoschus esculentus (L.) Moench (gombo, okra) is the vegetable most frequently used. Next is the red palm oil, which is prepared from fruits of the uncultivated `dura type' of Elaeis guineensis Jacq. Its oil is preferred by the local populations over the oil from cultivated types of oil palms because of its quality (see also Böni 1993, Böni et al. 1994). Palm oil is an important source of fat, often lacking in the diet in rural West Africa. In addition, palm oil provides carotenes, which contribute to the vitamin A supply. A daily intake of 5 g of red palm oil is sufficient to cover the RDA of an adult.
Eggplant (Solanum melongena L.) is also frequently consumed. The other vegetables listed are prepared less often; most of them are from uncultivated plants (fig. 1).
Basically, vegetables from uncultivated plants can be grouped into two categories:
· Highly appreciated specialities such as Elaeis guineensis dura type, Corchorus olitorius L., Ricinodendron heudelotii (Baill.) Heckel subsp. heudelotii, Solanum indicum L. subsp. distichum (Thonn.) Bitter.
· Vegetables that are eaten mainly when fresh vegetables form the fields are scarce. Solanum americanum Miller and Hibiscus congestiflorus Hochr. were recorded; nine others are known to have edible parts but were prepared so seldom that they were not recorded in the interviews. These vegetables contribute to food security, the importance of which need not be stressed.
Half the fruits consumed are from uncultivated species (fig. 2). The consumption of individual fruits depends on several factors:
· the availability of ripe fruits throughout the year; the most frequently consumed fruits are available during several months (coconut, papaya), whereas others are ripe only during a short period
· the productivity of the plants
· the preferences of the population
Figure 2. Fruit consumption in Zougoussi,
V-Baoulé, Côte d'Ivoire, in 1988-1989;
percentage of interviewed persons eating each fruit during the 24 hours preceding the interview (Herzog et al. 1994).
|A||Cocos nucifera||J||Annona senegalensis|
|B||Carica papaya||K||Mangifera indica|
|C||Saccharum officinarum||L||Borassus aethiopum|
|D||Ananas comosus||M||Lantana camara|
|E||Aframomum alboviolaceum||N||Napoleonaea vogelii|
|F||Spondias mombin||O||Landolphia hirsuta|
|G||Musa sapientum||P||Sarcocephalus latifolius|
|H||Citrus sinensis||Q||Persea americana|
|I||Psidium guajava||R||Vitex doniana|
The consumption also varies with the age groups. Lantana camara L., for example, is a small, relatively unattractive fruit from shrubs growing near the villages. It is eaten only by children. Landolphia hirsuta Beauvois on the other hand is highly appreciated by the whole population but the fruits, growing on a liana, are rather difficult to obtain. Therefore, the adults get the biggest share of it. Aframomum alboviolaceum (Ridley) K. Schum. is preferred by the elderly people.
The children, however, are the most important consumer group of wild fruits. For them in particular, the fruits are a good source of vitamins because they are eaten raw, whereas in prepared meals, a number of vitamins are affected by the preparation process. In the region, the uncultivated fruits are particularly rich in carotenes, vitamin C and vitamin B1. They also contain significant amounts of potassium and iron (table 1).
Table 1. Coverage of the recommended dietary allowances (RDA) with vitamins and minerals for a child (7-9 years) per 100 g edible portion of some uncultivated fruits (adapted from Herzog 1992 and Herzog et al. 1994)
|Vit.A||Vit.B1||Vit B2||Niacin||Vit. C||K||Mg||Fe||Ca|
(----------------------------------- mg ------------------------------)
|RDA 7-9 years||400||0,8||1,2||13,4||20||2000||220||8||500|
|100 g = x fruits||
(------------------ % of recommended dietary allowance ------------)
Sources: - no values (adapted from Herzog 1992 and Herzog et al. 1994)
The most important beverage, next to water, is the tea prepared from the leaves of Lippia multiflora Moldenke, a shrub growing in the savanna (fig. 3). It is usually prepared for breakfast. Palm wines are obtained from the sap of the palm trees Elaeis guineensis dura type and Borassus aethiopum Mart. The other beverages are of only marginal importance.
Figure 3. Consumption of beverages in
Zougoussi, V-Baoulé, Côte d'Ivoire, in 1988-1989;
percentage of interviewed persons claiming to have consumed a certain beverage during the 24 hours preceding the interview.
|A||`Thé de savane' (Lippia multiflora)|
|B||Palm wine (Elaeis guineensis)|
|C||Palm wine (Borassus aethiopum)|
|D||Other alcoholic drinks (spirits, beer, wine)|
|F||Beverages based on milk|
The seasonal consumption of palm wine varies between about 0.5 and 1 litre per person and per day throughout the year. With an alcohol content ranging between 2 and 6%, the alcohol consumption from palm wines is similar to that from wine and beer in European countries. The two palm wines complement each other. During the rainy season, the quality of the sap from the oil palm is insufficient and then Borassus is tapped instead and vice versa (Herzog et al. 1995).
Depending on the season, palm wine consumption accounts for 7 to 17% of the coverage of energy requirements of the population. In addition, they contain sufficient vitamins and minerals to meet significant parts of the RDA, namely for vitamin C, niacin, potassium and iron (table 2). For vitamin C, the intake even exceeds the recommended amount, and this is more marked for elderly people and for men-the groups of the population that consume the most.
Table 2. Energy and nutrients obtained from the palm wines of Elaeis guineensis and Borassus aethiopum in Zougoussi, V-Baoulé, Côte d'Ivoire, in 1988-1989. Percentage of RDA (mean values for the different groups of the population during the examination period) (Herzog et al. 1995)
|Energy||Vit. B1||Vit. B2||Niacin||Vit. C||K||Mg||Fe||Ca|
|(-------------------------------- % of recommended dietary allowance ------------------------------)|
Borassus aethiopum Mart., Hist. Nat. Palm. ed. 3, 1: 221. 1938
Vernacular name: [kue]
Common names: African fan palm / Palmyrah palm / Ron palm / Rônier
Description: The Borassus palm is characterized by a crown up to 8 m wide, forming 15-30 fan-shaped leaves up to 3.5 m long. The young palms are covered with dry leaf stalks, showing gradually fading leaf scars. The old trees (over 25 years) have a swelling of the trunk at 12-15 m above ground (at 2/3 of the height). Flowers are dioecious, yellowish. Male flowers are clustered in a branched spadix up to 1.5 m long. Female flowers have an unbranched and shorter spadix. The fruit (a drupe) is large (diameter about 15 cm), ovoid, orange to brown when ripe. The fibrous pulp contains 3 woody kernels with an albumen becoming hard when ripe.
Distribution: Guineo-Congolian and Sudanian savannas, centres of endemism; Guineo-Congolia/Sudania transition zones (Senegal, Mali, Côte d'Ivoire, Burkina Faso, Ghana, Nigeria).
Ecology: Borassus is abundant and characteristic in all types of savanna of the region. Up to 120 trees ha-1 occur, of which 40 can be tapped for palm wine and 20 are fruit producing. The fruits have a large edible part (around 500 g each) and are available from December to July.
Utilization: Of all plants in the region, Borassus probably is the one most intensively used by the local population. From roots to leaves, each part of the tree is useful for a certain purpose. Borassus is particularly appreciated because of its sap, which ferments to palm wine [kue za], the traditional Baoulé beverage. For palm wine tapping, the terminal bud of the tree is cut and the dripping sap of the phloem is collected in a receptacle. The cut is renewed twice every day for 3 to 4 weeks until the tree is exhausted and dies. During this period, a Borassus palm can yield about 200-250 litres of sap. Palm wine can be distilled to form `koutoukou'. This spirit often contains undesirable esters and free acids (Varlet 1956).
The fruits [kue ma] have a fibrous pulp that smells strongly from therbenthine. They are consumed raw or prepared, preferably with rice. The kernels (usually 3 per fruit) contain an albumen [kpoko], which before ripening is sweet and refreshing. The fruits are sometimes assembled on cleared, sandy locations at the village border. The germ [kule], which appears after a few weeks, is roasted and appreciated because of its bitter taste. While the fruits were not for sale on the local market, they are frequently sold along roads, as are the sprouted embryos.
In traditional medicine, palm wine is a component of several aphrodisiac preparations, as described also in Nigeria, in the Niger and in Senegal (Dalziel 1937, Kerharo 1968). The flower helps against aphonies, and young leaves are used to stop haemorrhages.
The strong trunks [kue bo] are very resistant against decay; they are therefore frequently used as posts and for the construction of bridges. The boards cut form the trunks [kue bui] are used for the construction of shower cabins. Adult leaves [sagro] are used for roofing whereas the young leaves, before unfolding, can be split into stripes [sagro nia ko] and woven into mats, baskets and other household objects. From the nerves of the leaves [sagro die] strings are prepared. The leafstalks [tiedre] are used as stakes. Their ending [koglo] can also be soaked in water to provide fibres [kue saka], which are used as sponges or filters.
Cultivation: Because palm wine tapping destroys the trees, the 200 inhabitants of the village of Zougoussi need 130 Borassus palms every year for local palm wine consumption. The natural regeneration of Borassus appears to be sufficient around Zougoussi, but in areas closer to roads the Borassus populations are reduced, due to increased palm wine tapping for urban markets. To compensate for this increased exploitation, the cultivation of Borassus would be easily possible-at least technically. There is a tradition of artificial germination as mentioned above and the planting of Borassus would require only a change of attitude, the germs being planted instead of used consumed. A major drawback, however, is the slow growth of Borassus: it takes 6 to 8 years until the trunk appears and another 25 years until the tree has reached its final size.
Instead of planting, the introduction of less harmful techniques for tapping would seem to be more promising. In other regions of West Africa the tapping process is interrupted after about 2 weeks. The tree is then left to recover and can be tapped again after about one year (Maydell & Götz 1971). In Indonesia with Borassus flabellifer L., the inflorescens (instead of the terminal bud) is cut to collect the sap. This procedure is less harmful for the tree, which can be exploited that way over a long period (Chrystopher & Theivendirarajah 1988a,b).
Annona senegalensis Pers. subsp. oulotricha Le Thomas, Flore du Gabon:102.1969.
Vernacular name: [amlu]
Common names: Wild custard apple / Annone africaine
Description: Generally a shrub growing from numerous root-shoots up to 2 m high (occasionally up to 6 m if protected from fire). The young stems are ferruginous, velvety to greyish tomentose, glabrous when old. The alternate leaves are simple, entire, up to 10 cm long and 7 cm wide, elliptic, ovate or ovate-elliptic, very fragrant when crushed; the upper side is pubescent, the lower side is distinctly brighter and with prominent venation. The yellow-greenish, waxy flowers hang down from peduncles about 1-2 cm long, solitary or 2-4 together, fasciculated, bell-shaped, about 1.5 cm long. The fruit (a syncarp) is up to 3 cm long, ovoid, yellow-orange when ripe and characterized by numerous smooth elevations on the surface. Numerous seeds are embedded in the yellow, farinose fruit pulp.
Distribution: Guineo-Congolian and Sudanian savannas, centres of endemism; Guineo-Congolian/Sudania transition zones (Senegal, Sierra Leone, Mali, Côte d'Ivoire, Cameroon).
Ecology: Annona occurs mainly in tree savannas where up to 1500 fruit-producing shrubs per hectare were counted. Edible fruits are available in April and May only. The individual production is relatively low (20-30 fruits per shrub), each fruit weighing around 25 g, of which 16 g are edible.
Utilization: The fruits are highly appreciated by the regional population; almost everybody knows and consumes them. However, fruits fallen to the ground are not collected as they are reputed to attract snakes. It was reported very early that the fruits are edible (Sébire 1899) and their consumption is common all over West Africa.
In traditional medicine, wood and leaves are used to heal sprains. The roots, when mixed with the fruits of Xylopia aethiopica (Dunal) A. Rich. or the flowers of Hibiscus sabdarifa L., help against nervous excitement. The leaves are used to heal asthenia and to cure Guinea worm. For the latter purpose also roots and sometimes a mixture of the bark and the leaves of Parkia biglobosa (Jacq.) G. Don are added. In Senegal, Annona is used similarly to treat Guinea worm (Sébire 1899), whereas in Nigeria, the consumption of many fruits is said to have the same effect (Dalziel 1937).
Domestication: The domestication of Annona has been repeatedly proposed, starting with the botanist Chevalier (1948). It appears to be promising, the fruits being appreciated by the population. Annonaceae of American origin have been domesticated successfully. However, a significant effort of selection and breeding would be necessary to improve the relation between the seeds and the pulp (now only 66% of the fruit is edible) and the productivity of the shrubs. A major drawback comes from Annona's reputation of attracting snakes. This must be taken into account when cultivation is proposed.
Corchorus olitorius L., Sp. Pl.:529. 1753
Vernacular name: [korala]
Common name: Jute
Description: Annual herb up to 2.5 m high, often suffrutescent. The stems are woody at the base, fibrous, sparsely pilose to glabrescent. Leafs alternate; they are entire and subglabrous. The leaf-blades are 4-15 cm long and 1-5 cm wide, elliptic or ovate, chartaceous. Inflorescens in 1-2 (or -3) flowered fascicles. Pentamerous flowers bracteolate. The stamens are numerous. The fruit (a capsule) is cylindrical, woody, 2.5-6.0 cm long, 0.3-0.7 cm wide, splitting into 5 (-6) valves tapering to a short beak. Seeds are numerous, blackish, 0.1-0.2 cm long, pyramid-shaped.
Ecology: Corchorus is often associated with human presence; it mainly occurs on agricultural fields, where it is protected by the farmers. The leaves, available throughout the year, are collected regularly by women.
Utilization: The leaves are used to prepare stew or soup [korala] throughout West Africa. The species probably originates from India, where it has traditionally been cultivated. It is probably one of the first vegetables to have been introduced in sub-Saharan Africa. It is cultivated in numerous gardens and used to prepare soups and side dishes comparable to European spinaches. The sauce [korala] is highly appreciated and is the most frequently prepared leaf in the village of Zougoussi.
In traditional medicine, the seeds are used against vertigo. Textile uses of the fibres are unknown in the region.
Domestication: Whereas Corchorus is a common agricultural crop in northern Africa, Nigeria and Cameroon (e.g., Fawusi 1983, Stevels 1990), it is semi-domesticated in Côte d'Ivoire. On the villagers' fields, it grows spontaneously, then is protected by the farmers and not removed as other weeds. Around the urban centres, Corchorus is planted and produced in horticultural areas. Siemonsma (cited by Terrible 1983) estimates that over 20% of the leaves sold on Ivorian markets are from Corchorus.
The data indicate that the contribution of uncultivated plants to the human nutrition is significant. This is further confirmed by ongoing investigations in a second village (Bringakro) of the region (Müller, in preparation). This indicates that in nutritional surveys, where gathered products are not usually taken into account, the intake of energy and nutrients is underestimated. This survey is therefore of considerable importance to our knowledge of nutrition in the humid region of West Africa.
The extension of agricultural land use has detrimental effects on gathering activities. The forest and the savanna, where the products can be found, are driven back. Furthermore, the orally transmitted knowledge about wild plants tends to get lost as lifestyles change and children go to school and learn other non-traditional ways of life.
Some of the traditional food products can be replaced by substitutes, but the domestication of the more important plants would also be possible. There are, however, some major constraints. There is normally a reason why certain species have not been domesticated up to now. It is clear that the farmers will not be ready to make the `extra effort' of planting and domesticating these plants if:
· the product is still available in sufficient quantity and quality from wild plants
· the product has a low preference
· attractive substitutes exist
· there are major technical difficulties
the plant has a bad image, such as Annona senegalensis, which is said to attract snakes and a number of uncultivated vegetables thought of as `famine food', or `food for the poor'
There are two situations in which the farmers in the V-Baoulé will consider the effort of domestication as justified:
· If there are market opportunities. Although in the V-Baoulé, food security is not much of a problem, the production of marketable goods would be a major incentive.
· If a product that is indispensable for household consumption is no longer available and there is no substitute for it.
In both cases, the farmers can be expected to make the first steps towards domestication. Technical support, however, with propagation methods and improved genetic material, may help them to progress more rapidly and to achieve better results.
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Plate 5. In central Côte dÍvoire,
palm wine is tapped from Borassus aethiopum
by cutting the terminal bud, which eventually leads to exhaustion and death of the tree.
The introduction of less harmful techniques might lead to a more sustainable use of this valuable resources.
(photo: F. Herzog)