CELL-WALL POLYSACCHARIDES FROM SOYBEAN (GLYCINE MAX.) MEAL - ISOLATION AND CHARACTERIZATION

Cell wall material was isolated as water unextractable solids (WUS) fr om soybean meal. The isolation of WUS yields a fraction that contains 92% of the polysaccharides present in soybean meal and only a few othe r components. Arabinose, galactose, uronic acids and glucose (cellulos e) were the major constituent sugars. WUS was sequentially extracted w ith chelating agent (chelating agent soluble solids, ChSS), dilute alk ali (dilute alkali soluble solids, DASS), 1 M alkali (1 M alkali solub le solids, 1 M ASS) and 4 M alkali (4 M alkali soluble solids, 4 M ASS ) to leave a cellulose-rich residue (RES). ChSS was the major extract, yielding 38% of the polysaccharides present in the WUS. All extracts and the residue were characterised by their sugar composition and thei r molecular-weight distribution. The extracts ChSS and DASS were fract ionated by anion exchange chromatography. They showed identical elutio n patterns: an unbound fraction, five bound fractions of which one fra ction eluted only with alkali. Anion exchange chromatography was also performed after saponification of both pectin-rich extracts, again res ulting in identical elution patterns. (C) 1998 Elsevier Science Ltd. A ll rights reserved.