11. Studies on the Carbohydrates of Soybeans

V. A Hemicellulose Fraction Soluble in Hot Water. Isolation and Component Sugar Determinations

Abstract

Dehulled and defatted soybean meal was treated with 0.2 sodium hydroxide to give a sugar-free protein-extraction residue, from which hot-water-soluble hemicellulose was precipitated by adding ethanol to the concentrated hot-water extract. The hemicellulose was purified through the copper complex formed by adding Fehling's solution and acetone. Its decomposition point was 194_??_5° and [a]_??_+97.5° and it consisted of pentoses (arabinose and xylose) 17.8% (as pentosan), uronic acid (galaeturonio acid) 19.2% (as lactone), and hexose (galactose) 41.9% (as galactan). The methods of analyses are described in detail.