92 The use of HPAEC-PAD in comparison to (^1)H-NMR for determination of the ratio of (1,4) to (1,3)-linkages.

J. P. ROUBROEKS, R. Andersson, and P. Åman. Department of Food Science, SLU, P.O. Box 7051, SE-750-07 Uppsala, Sweden.

Little information is known about water unextractable mixed-linkage beta-D-glucan from rye bran. This polysaccharide could be of interest with respect to water-holding capacity, plasticity of the cell wall, interactions with other cell wall constituents and possible nutritional properties. HPAEC-PAD has been used to determine the molar ratio of cellotriosyl to cellotetraosyl units. The response factors of the oligosaccharides involved were determined, showing a higher sensitivity of the HPAEC-PAD for the trisaccharide. Our study resulted in a molar ratio of 1.94 for cellotriosyl to cellotetraosyl units, which corresponds to a (1,4) to (1,3)-linkage ratio of 2.34. Besides this method, (^1)H-NMR could be used to establish the linkage ratio directly. Integrals of the anomeric proton signals gave a linkage ratio of 2.31. This indicates that both methods can be used for determination of the linkage ratio.