International Journal of Biology Research

Authors
Dr. Mariappan Senthilkumar

Abstract
The yam is common name for the genus Dioscorea which is used as staple food of people in the tropics, but certain wild varieties are inedible because of the toxic substances present, some of which have pharmaceutical properties. The wild yam tubers consumed by the tribal Malayali’s of Dharmapuri district (Dioscorea bulbifera, D. deltoidea, D. hispida, D. oppositifolia, and D. pentaphylla) were evaluated for its nutritional quality. This paper reveals the proximate composition, mineral profiles, total protein, carbohydrate, fat, vitamin C, β-carotene, starch and total soluble sugar content. The toxic principles like phenols, tannins, hydrogen cyanide, oxalate, amylase inhibitor activity and trypsin inhibitor activity were also analyzed using standard methods. Treatments like soaking, cooking and autoclaving and their effects on changes toxic principles were investigated in five tuber samples. Soaking reduced the levels of antinutrients up to 73% whereas cooking and autoclaving (30 min.) reduced the toxic contents to a greater extent (< 73%). The amylase and trypsin inhibitor activity showed only slight reduction (up to 47%) in toxic principles after treatments. There is a significant difference (p<0.05) of values were observed among the Dioscorea species and were found to have high nutrient and low antinutrient values.