OLIGOSACCHARIDES OF BIRCH SAP

Abstract

Fractionation of concentrated fresh sap from white birch (Betula papyrifera) yielded polysaccharide material (mainly arabinogalactan), oligosaccharides, and D-glucose and D-fructose. Separation of the oligosaccharides by a combination of charcoal column and filter paper chromatography yielded seven sugars (I–VII). These were identified as sucrose (I); 6G-fructosylsucrose [Formula: see text] (II); a F-glucosylsucrose (III); gentiobiose [Formula: see text] (IV); melibiose [Formula: see text] (V); manninotriose [Formula: see text] (VI); and verbascotetraose [Formula: see text] (VII). The small amount of sucrose found in the sap and the absence of raffinose, stachyose, and verbascose indicated that enzymic hydrolysis by a β-fructofuranosidase had occurred in the cells or vessels of the tree. The oligosaccharides are not related in either structure or composition to the polysaccharides present in the sap and wood.