STUDIES ON THE SIMULTANEOUS DETERMINATION OF ACIDIC AND NEUTRAL SUGARS OF PLANT-CELL WALL MATERIALS BY HPLC OF THEIR METHYL GLYCOSIDES AFTER COMBINED METHANOLYSIS AND ENZYMATIC PREHYDROLYSIS

A method which involves enzymic hydrolysis followed by methanolysis and separation of their methyl glycosides by HPLC was applied to complex polysaccharides from three fibre preparations (pea hulls, sugar-beet pulp and wheat bran). The results were compared to those obtained by (1) methanolysis without enzymic prehydrolysis, (2) gas chromatography of the alditol acetates of the neutral sugars released by acid hydrolysis, and (3) colorimetric determination of the uronic acids. Methanolysis alone allows the estimation of non-cellulosic polysaccharides (pectins and hemicelluloses), whereas combined methanolysis and enzyme prehydrolysis also leads to the determination of cellulose, except for wheat bran which is a highly lignified plant cell wall material.