CARBOHYDRATES OF SUNFLOWER HEADS

Abstract

Extractive-free, ash-free sunflower seed heads contained lignin (12.3%), pectin (27.5%), alkali-soluble polysaccharides (8.2%), and α-cellulose (52.0%). Pectin and polysaccharides were separated by successive extraction of the seed heads with ammonium oxalate – oxalic acid solution and 5% aqueous sodium hydroxide. The pectin was 37% esterified with methyl groups and yielded only galacturonic acid when hydrolyzed. The polysaccharides yielded, on hydrolysis, a mixture of neutral sugars and an aldobiouronic acid. The neutral sugars consisted of D-xylose (59.3%), D-glucose (23.5%), D-galactose (16.2%), and traces of arabinose and rharnnose. Fractionation of the polysaccharide acetate indicated that the three main sugars were constituents of three different polysaccharides. The aldobiouronic acid (1.53% of the polysaccharides) was shown to be 3-O-α-(D-glucopyruronosyl)-D-xylopyranose.