Abstract
Hydrocolloids containing cellulose microfibrils having a diameter smaller than 3nm are found to be present in the berries of mistletoe, Viscum album L., and the outer epidermis layer of basil seeds. The cellulose microfibrils in V. album are tightly coiled in a rope-like fashion with their axes perpendicular to the long axis of the cells in the viscin tissue. In the case of basil, the cellulose microfibrils are also tightly coiled in a doughnut-like fashion in the cylindrical cells present at the outer epidermis of their seeds. When the viscin tissues and cylindrical cells adsorbed water, the cellulose microfibrils became unwound to be perfectly aligned along the stretching direction. The hydrocolloids are present as a kind of cellulose-hemicellulosic polysaccharide composite. In both hydrocolloids, the presence of highly branched arabinogalactan in addition to (1, 4)-linked xylan and glucomannan is noted by methylation analysis. The remainder of the glucose and mannose after partial acid hydrolysis of the hydrocolloids indicates that glucomannan type hemicellulose is closely attached to cellulose while acidic polysaccharides may act to keep cellulose-hemicellulose composite soluble in water.
