ABSTRACT

Yam is a staple carbohydrate food for a large section of the population in the tropics. The chemical composition of the tuber varies with species and cultiver with water accounting for about 2/3 of the fresh weight, carbohydrate (mostly starch) '4, while proteins, sugars minerals and vitamins are only present in minute quantities (Onwueme, 1978). The poor nutritional quality of yam. is improved upon by other foods like vegetables, meat, fish and legumes which yam is eaten with traditionally. The most important food yam in Africa is the indigenous Dioscorea rotundata (white yam) which exists in a wide range of cultivers. (Rasper and Coursey, 1967). Yams have been utilized in Africa almost entirely for the preparation of food at the domestic level. Yams could be boiled or pounded into fufu. Fufu is probably the most popular and most traditional form in which yam is eaten in West Africa. Dioscorea rotundata and Dioscorea cayanesis make better pounded yam (Onwueme, 1978, Okpokiri, 1984). The main traditionally processed form of yam is in Nigeria is 'amala' (a brown yam flour)-popular in Oyo and Ogun States areas of the Western Nigeria (Adesuyi, 1973). Yam could be fried and eaten with stew or salted oil or sauce. Yam could also be eaten as mashed (most common in West Indies), roasted or baked and fried yam balls (preferably Dioscorea alata_because of the greater amount of binding mucilage). Some examples of different species of Yam include, Dioscorea alata, Dioscorea arachnic, Dioscorea bartlett, Dioscorea bulbifera, Dioscorea continifolia, Dioscorea cumin ghii, fandra, Dioscorea flabellifolia, Dioscorea hastata, Dioscorea luzonensis, Dioscorea inacabilla, Dioscorea mamillata, Dioscorea man genotiana, Dioscorea mexicana, Dioscorea micro botiya, Dioscorea mu1tflora, Dioscorea minima, Dioscorea inundtii, Dioscorea minutijiora, Dioscorea numinulana, Dioscorea obiculata, Dioscorea opposita, Dioscorea oryzetorum, Dioscorea ovinala, Dioscorea pentaphylla. Dioscorea prae/zensilis, Dioscorea preussii, Dioscorea pseudotomentosa, Dioscorea pynaerti, Dioscorea Sansbarensis, Dioscorea Smilaqfolia, Dioscoreau Sylvatica Dioscorea trifida, Sinilcifolia, Dioscorea triloba, Dioscorea Zingiberensis ( Viclery and Vickery 1979).