CELL 275 |
| Arabinoxylan has been extracted from barley husks and endosperm fiber using different methods and the chemical composition and detailed structure has been determined. Barley husk arabinoxylan was found to have longer branches with a terminal xylose unit on the arabinose, and also glucuronic acid substituents, as shown by NMR. Barley fiber arabinoxylan on the other hand had disubstituted xylose residues. The Ara/Xyl ratio was a lot higher in the fiber sample, 0.63 compared to 0.22 for the husk arabinoxylans. The extraction process has been scaled up to pilot scale with promising results. The focus when designing the isolation process has been mild conditions and minimal use of chemicals to preserve high molecular weight. Enzymes were used to degrade glucans and proteins, and the arabinoxylan was extracted by alkali. Films have been made by water casting and material and barrier properties of these have been evaluated. The isolated arabinoxylan formed films without addition of external plasticizer. The degree of arabinose substitution had a large effect on water holding capacity and plasticization of the material. The films were transparent, strong, rather stiff and moisture sensitive. They had good gas barrier properties, and thus have a potential application as biodegradable oxygen barrier films in multilayer food packaging. |
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Renewable Chemicals from Plant and Animal-Based Agricultural Wastes
12:50 PM-4:45 PM, Thursday, April 10, 2008 Morial Convention Center -- Rm. R07, Oral
Division of Cellulose & Renewable Materials |