Evolution of castalagin and vescalagin in ethanol solutions. Identification of new derivatives.

Brandies, cognac, armagnac, whiskeys, and rums are aged in oak barrels to improve their organoleptic properties. During this period, numerous compounds such as ellagitannins are extracted from the wood and can subsequently be transformed into new derivatives by chemical reactions. Model solutions of castalagin and vescalagin have been studied to determine the behavior of polyphenols in ethanol-water.

Structural analysis of cyclamen seed xyloglucan oligosaccharides using cellulase digestion and spectroscopic methods.

Xyloglucan polymers have been isolated from cyclamen seeds and characterized by both liquid and CP-MAS 13C NMR spectroscopy. Treatment of the polysaccharides with cellulase from Trichoderma viride afforded XG oligomers which have been studied with both mass spectrometry and NMR spectroscopy. The repeating unit in the intact polymers and the most abundant hydrolysis product correspond to the Gal1 Xyl3 Glc4 (XXLG) fragment.

Conformational analysis of disaccharides using molecular dynamics and NMR methods.

The internal dynamics of four disaccharides, a galacturonic acid dimer, beta-ethyl-lactoside, sucralose and arabinobiose, have been studied using molecular dynamics and nuclear magnetic resonance methods. Theoretical motion models, which include order parameters and correlation times for internal motions, were extracted from dynamics trajectories in vacuo. In parallel, theoretical NOESY volumes were calculated from averaged distance matrices using 'model-free' spectral densities.

Internal motion in carbohydrates as probed by n.m.r. spectroscopy.

In the present study a combination of proton and carbon relaxation rates have been measured for several oligosaccharides at different temperatures. Correlation times, which have been calculated from both sets of data, have been compared in an attempt to establish the relative rate of internal motion. All the data suggest that these motions are not slow with respect to the overall tumbling.

New investigations of the structure of grape arabinogalactan-protein.

The structure of an arabinogalactan-protein (AGP) isolated from grape juice was studied by methylation analysis, n.m.r.

Structural features of the cell-wall polysaccharides of Asparagus officinalis seeds.

The fine structure of a beta-)1----4)-linked glucomannan from Asparagus officinalis has been determined by n.m.r.