Physicochemical study of yam starch / Rohani Embong

The purpose of this study is to extract starch from yam (genus Dioscorea) and to characterize the physicochemical properties of pink and white yam tuber and its starch. The pink yam gave starch yield of 18.15% and white yam gave yield of 15.60%. Proximate composition studies showed that pink yam tuber contain 74.80% moisture content, 2.40% protein, 1.28% fiber, 0. 78% ash and 0.05% fat. White yam tuber contain 69.40% moisture content, 1.45% protein, 1.26% crude fiber, 0.67% ash and 0.07% fat. Starch extracted from pink yam tuber contain 9.68% moisture content, 0.19% protein, 0.68% crude fiber, 0.27% ash and 0.03% fat. Starch extracted from white yam tuber contain 9.42% moisture content, 0.20% protein, 0.80% crude fiber, 0.33% ash and 0.02% fat. The amylase content of pink and white yam starch was 0.3 730 mg/100 g and 0.1826 mg/100 g respectively. Gelatinization temperature for pink and white yam starch at concentration of 6% was 85 to 100°C and 84 to 100°C respectively. Its gel was hard and stable after cooling.