In:
Polymer International, Wiley, Vol. 51, No. 2 ( 2002-02), p. 117-124
Abstract:
Seven hemicellulosic preparations were obtained from barley straw by extraction with 1.5% H 2 O 2 at pH 12.0 for 14 h at 45 °C with extractant to straw ratios of 10:1, 13:1, 15:1, 18:1, 20:1, 25:1 and 30:1. The respective yields of dissolved hemicelluloses were 28.4 wt%, 28.8 wt%, 29.7 wt%, 30.1 wt%, 30.6 wt%, 30.8 wt% and 30.8 wt% or dry barley straw, corresponding to release of 78.7%, 79.8%, 82.3%, 83.4%, 84.8%, 85.3% and 85.3% of the original hemicelluloses. The polymers were mainly composed of xylose, arabinose, glucose, galactose and 4‐ O ‐methyl‐ D ‐glucuronic acid (59.3–62.6%, 19.7–22.0%, 8.8–12.5%, 5.6–6.9% and 5.8–6.7%, respectively) and had weight‐average molecular weights of between 38 470 and 41 050 g mol −1 . 13 CNMR spectroscopy confirmed the results obtained by chemical methods, and showed that the hemicellulosic fraction was mostly by L ‐arabino‐(4‐ O ‐methyl‐ D ‐glucurono)‐ D ‐xylan. More importantly, it was found that lignin provides some protection for the hemicelluloses in barley straw against attack by hydrogen peroxide. © 2002 Society of Chemical Industry
Type of Medium:
Online Resource
ISSN:
0959-8103
,
1097-0126
Language:
English
Publisher:
Wiley
Publication Date:
2002
detail.hit.zdb_id:
2004753-8
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