Abstract

Yam (Dioscorea species) is one of the most important food crops in West Africa. It is a major source of carbohydrates and nutrient energy for many people in tropical countries. Like many other foods, roots and tubers are rarely eaten raw. They normally undergo some forms of processing which makes them more palatable, digestible and safe for human consumption. Freshly harvested tubers of Dioscorea rotundata were peeled, washed and diced and subjected to different domestic processing techniques namely: Drying, roasting, boiling and frying. The flour was evaluated for proximate and amino acid composition. Glutamic acid was the most concentrated amino acid, with the drying process recording the highest value. Histidine, an essential amino acid showed a higher value than the FAO standard for the four techniques. The lysine contents were comparable with the reference egg protein. Total aromatic amino acid and total sulphur-containing amino acids gave values comparable with FAO/WHO/UNU standards. In general, the amino acid content was significantly higher (p<0.05) when the yam was subjected to drying process, suggesting that D. rotundata flour has potential as a high quality protein source, hence  can be exploited to enhance protein quality of diet for adults and weaning/complimentary feeding for children.

Key words: White yam, Dioscorea rotundata, amino acid.