ISOLATION AND CHARACTERIZATION OF HEMICELLULOSES FROM SUNFLOWER HULLS

The hemicelluloses extracted from sunflower hulls by repeated alternating oxidative and alkaline treatments were purified by precipitation with Cetavlon and then ion-exchange chromatography on DEAE-trisacryl. The resulting fractions were examined by hydrolysis, methylation, GLC-MS, and NMR spectroscopy. The hemicelluloses are of the glucuronoxylan type with the following structure --> 4)-beta-D-xylp-(1 --> 4)-[4-0-Me-alpha-D-GlcpA-(1 --> 2)]-beta-D-xylp-(1 -->. The polysaccharides differed in the amount of branching; the ratio of the main fraction 4-O-MeGlcA:Xyl was 1:8-9.