pectins and proanthocyanidin

The interactions between pectins of different degrees of esterification (DE) and highly galloylated persimmon tannins with average degrees of polymerisation (DP26 and DP5) were investigated by UV-Vis spectrophotometry, dynamic light scattering, transmission electron microscopy, isothermal titration calorimetry and pyrene fluorescence methods Pectins displayed strong effects on the self-aggregation of persimmon tannins and improved the homogeneity of condensed tannin aggregates. The interaction between tannins and pectins may result from hydrogen bonding and hydrophobic interactions; by contrast, electrostatic interactions, which involve charged molecules in general, played no dominant role. In addition, the presence of gallate moieties in the high-polymerisation proanthocyanidin could enhance affinity with highly methylated pectins. Stronger association was observed with the high-polymerisation tannins (DP26) with high-methoxyl pectin (DE74) (Ka=(8.50±3.0)×10

Topics: Diospyros; Esters; Fluorescent Dyes; Fruit; Gallic Acid; Hydrogen Bonding; Hydrophobic and Hydrophilic Interactions; Kinetics; Methylation; Pectins; Proanthocyanidins; Pyrenes; Spectrometry, Fluorescence; Tannins; Thermodynamics

Leaves of sericea lespedeza exhibit a high proportion of condensed tannin, resulting in poor forage quality. The white rot fungi Ceriporiopsis subvermispora and Cyathus sterocoreus are known to preferentially degrade lignin in a variety of plants and were evaluated for their ability to degrade condensed tannin from sericea leaves with the aim of improving digestibility. Relative levels of condensed tannin, cutin, pectin, and cellulose were monitored as a function of fungal treatment by solid-state cross-polarization and magic angle spinning 13C nuclear magnetic resonance spectroscopy. Total soluble phenolics, soluble tannins, and soluble and insoluble proanthocyanidin levels in fungus-treated and control samples were measured by established chemical techniques. Results indicate that both species of fungus preferentially degrade condensed tannin and that C. subvermispora is markedly superior to C. stercoreus in this capacity.

Topics: Anthocyanins; Basidiomycota; Biodegradation, Environmental; Cellulose; Fabaceae; Magnetic Resonance Spectroscopy; Membrane Lipids; Pectins; Phenols; Plant Proteins; Plants, Medicinal; Polyporales; Proanthocyanidins; Tannins