Paper Chromatography of Flax Fibre Polyuronide Hemicellulose

Abstract

IT is well known that pectic substances are broken down during the retting of flax. There is evidence that other polyuronides also occur in flax straw and are attacked in retting¹. Their constitution is therefore of great interest in flax research. The sugar constituents of the polyuronide hemicellulose have been investigated. This substance was obtained from fibre separated from flax straw by purely mechanical means without previous retting. Finely ground fibre was extracted successively with ether, petroleum ether, ethanol and water. Pectic substances were removed with seven 30-min. extractions with boiling 0.5 per cent ammonium oxalate solution. The residue, after washing with water, ethanol and ether followed by air-drying, was extracted twice for 24 hr. with cold 4 per cent sodium hydroxide solution. The filtered extract was acidified with glacial acetic acid and the hemicellulose was precipitated with ethanol. The precipitate was well washed and dried from ethanol and ether. Approximately 3 gm. of polyuronide hemicellulose was obtained as a slightly greyish powder, lignin content 1.8 per cent, uronic acid anhydride content 7.1 per cent (19 per cent hydrochloric acid method²).