Polysaccharides of lotus root

The lotus (Nelumbo nucifera Gaertn.) is a crop of local importance in south -east Asia, both for the starchy roots and for the nut-like seeds. The mono saccharide composition of whole lotus root and extracted polysaccharide fra ctions were analysed by anion exchange high performance liquid chromatograp hy (HPLC). The major polysaccharide was starch but the lotus root also cont ained appreciable quantities of other non-starch polysaccharides. Lotus roo t flour was fractionated by sequential extraction with cold water, hot wate r, and 3% NaOH. Analysis of the fractions suggested the probable presence o f a water-soluble arabino-galactan, mannan, and fructan. Lotus root is a us eful raw material for starch production in China although commercial starch tested was found to contain arabinogalactan. In a model cooking for lotus root, the polysaccharides were extracted and those remaining in the tissue were quantified. The texture of lotus roots was analysed and the fibrous ce llulosic nature of the root limited softening after cooking. Lotus seeds we re also tested and found to have a predominantly starchy endosperm with the presence of pectic type polysaccharides being indicated.