The Isolation and Characterization of a Starch Polysaccharide from the Leaf Tissue of the Apple Tree (malus Malus)”

In a previous investigation conducted in this laboratory (1) a starch polysaccharide, apparently identical with the watersoluble component of the common cereal and tuber starches, was isolated from the woody tissue of the apple tree (Malus malus). Thus it appears that starches of widely different origin may contain a common water-soluble polysaccharide. Through an application of the method (2) used above a crude starch polysaccharide was obtained from the leaf tissue of the apple tree (Malus malus), which was separated into a watersoluble and a water-insoluble fraction. The water-soluble fraction was an amorphous white powder, [cy]:’ = +172”, which reacted with aqueous iodine-potassium iodide to give a blue color that disappeared on heating and reappeared on cooling. As this material contained minor quantities of erythrodextrin and pentosan, it was further purified by forming the iodine-iodide complex, which after precipitation with half saturated ammonium sulfate (3) was decomposed with silver nitrate. This procedure yielded an amorphous white polysaccharide which was soluble in water and formamide and possessed a specific rotation of [a]:’ = + 185”. An aqueous solution of the purified starch polysaccharide produced a pure blue color with the iodine-iodide reagent. Elementary