pectins and pyrene

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