Hemicellulosic polymers of cabbage leaves |
| |
Authors: | Barry JH Stevens Robert R Selvendran |
| |
Institution: | A.R.C. Food Research Institute, Colney Lane, Norwich, NR4 7UA, U.K. |
| |
Abstract: | The hemicellulosic polymers of depectinated cell-wall material of immature cabbage leaves have been extracted by alkali, fractionated by ion-exchange chromatography and their structural features studied. In the 1 M potassium hydroxide-soluble fraction the main polymers are arabinoxylan-xyloglucan-pectic, arabinoxylan-pectic-protein and arabinoxylan-xyloglucan-pectic-protein complexes. Small amounts of polysaccharide-protein-polyphenol complexes are also present. In the 4 M potassium hydroxide-soluble fraction the predominant polymers are two xyloglucans, the major one of which appears to have ca 10% of(1 → 4)-linked and 3% of(1 → 4,6)-linked mannose residues associated with it, and both have terminal galactose, fucose and possibly arabinose residues in the side chains. Methylation analysis of the oligosaccharides, formed by degradation with cellulase, and partial hydrolysis of the methylated xyloglucan, followed by re-methylation with CD3I, have enabled the formulation of a tentative structure which is similar to other plant galactoxyloglucans. It was not possible to establish whether the mannose residues are part of an associated glucomannan or whether they are an integral part of the glucan backbone. The general structural features of the hemicellulosic polymers are discussed in the light of these results. |
| |
Keywords: | Cruciferae cabbage cell-wall material hemicelluloses xyloglucan arabinoxylan pectic substances protein cellulose degradation oligosaccharides methylation analysis |
本文献已被 ScienceDirect 等数据库收录! |
|