Cell wall polysaccharides of Chinese Wolfberry (Lycium barbarum): Part 1. Characterisation of soluble and insoluble polymer fractions

Water-soluble polysaccharides (WSP) and insoluble cell wall material (CWM) were isolated from Wolfberry fruit (Lycium barbarum). WSP were fractionated by treatment with a quaternary ammonium salt and anion-exchange chromatography. Pectic polysaccharides were major components but a glucan, xylan and arabinogalactan-proteins (AGP) were also present. CWM was fractionated into pectic and hemicellulosic polysaccharides by a sequential solvent extraction. The former were rhamnogalacturonans with varying degrees of branching of the backbone. A (4-O-methyl-glucurono)xylan was the predominant hemicellulose. The additional presence of xyloglucan and a mannan-based polymer, strongly attached to the cellulose fibrils was indicated. Of the 6.8% total polysaccharide content of Wolfberry fruit, 1.2% was readily water soluble, 5.6% insoluble and 0.3% was readily soluble AGP.