Xyloglucan from soybean (Glycine max) meal is composed of XXXG-type building units

Soybean cell wall material was depectinated by extraction with a hot chelating agent and a cold dilute alkali. The hemicelluloses were solubilised from the residue with 1 and 4 M KOH solutions, resulting in 1 M Alkali Soluble Solids (1 MASS) and 4 M Alkali Soluble Solids (4 MASS) fractions. The polysaccharides extracted with 1 M KOH were fractionated by ion-exchange chromatography, yielding a neutral and a pectic population. The sugar composition of the neutral population indicated the presence of xyloglucans and possibly xylans. Enzymatic degradation with endoxylanases and endo-glucanases showed the presence of xyloglucans only. Analysis of the digest formed after incubation of the neutral population with endo-glucanase V using both HPAEC and MALDI-TOF MS showed the formation of the characteristic poly-XXXG xyloglucan oligomers (XXG, XXXG, XXFG, XLXG, and XLFG).