Chemical Composition of Mucilage of Chinese Yam

Dioscorea opposita Thunb. cv. Nagaimo

Abstract

Chinese yams were harvested in the middle of November in 1986 and were ground immediately after harvesting. The mucilage of the ground solution was purified by using sodium dodecylsulfate (SDS). Chemical composition was determined for the purified mucilage. Moreover, viscosity of the purified mucilage was evaluated using a rotationary viscometer. The results obtained were as follows: (1) Mucilage of the Chinese yams could be purified by using SDS. The protein was removed gradually from the mucilage without lowering the viscosity. (2) The purified mucilage contained 40% polysaccharide, 2% protein, 24% ash and 3% phosphorus. (3) The polysaccharide fraction of the purified mucilage consisted of mannose 80% and small amounts of fructose, galactose, xylose and glucose. (4) The viscosity of thepurified mucilage increased with a decrease in the mucilage concentration showing typical behavior of an electrolytic polymer. Furthermore, the intrinsic viscosity value for the purified mucilage was estimated to be 400.