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12. Yam: Technological Interventions
Rahman Akinoso1 and Olufunmilola A. Abiodun2
1Department of Food Technology, University of Ibadan, Oyo State, Nigeria
2Department of Home Economics and Food Science, University ofHorin, Kwara State, Nigeria
12.1 Introduction
Yam belongs to the family Dioscoreaceae and the genus Dioscorea. The genus includes about 600 species of which 50–60 are cultivated for food and pharmaceutical purposes (Craufurd et al., 2001). The important food species are D. rotundata (white yam), D. cayenensis (yellow yam or yellow guinea yam), D. esculenta (lesser yam, potato yam or Chinese yam), D. bulbifera (aerial potato yam), D. trifida (cush-cush yam) and D. opposita also known as D. japonica (cinnamon yam) (Craufurd et al., 2001). The varieties of yams grown are recognized by the range and colour of their leaves and tubers as well as by the direction of their stem twining as they climb (Okigbo and Nwakamma, 2005). It contributes more than 200 dietary calories per capita daily for more than 150 million people in West Africa and serves as an important source of income for the people (Babaleye, 2003).
Yam is highly regarded and closely integrated into the social, cultural, economic and religious aspects of life in some production areas (Maalekuu et al., 2014). Like other agricultural produce, yams are generally abundant and sold cheaply at harvest time, but later become scarce and expensive (Osunde, 2008). The scarcity of yam during the off-season in the yam zone may be due to wastage during storage, poor handling of the crop and inefficient methods of processing and preservation. A substantial amount of yam is lost during storage due to two major factors, namely the endogenous factors such as physiological factors which include transpiration, respiration and germination and exogenous factors like insects, pests, nematodes, rodents, rot bacteria and fungi on the stored yam product (Osunde, 2008; Wilson, 1980).