<?xml version='1.0' encoding='UTF-8'?><xml><records><record><source-app name="HighWire" version="7.x">Drupal-HighWire</source-app><ref-type name="Journal Article">17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Vernhet, A.</style></author><author><style face="normal" font="default" size="100%">Pellerin, P.</style></author><author><style face="normal" font="default" size="100%">Prieur, C.</style></author><author><style face="normal" font="default" size="100%">Osmianski, J.</style></author><author><style face="normal" font="default" size="100%">Moutounet, M.</style></author></authors><secondary-authors></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Charge Properties of Some Grape and Wine Polysaccharide and Polyphenolic Fractions</style></title><secondary-title><style face="normal" font="default" size="100%">American Journal of Enology and Viticulture</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">1996</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1996-01-01 00:00:00</style></date></pub-dates></dates><pages><style  face="normal" font="default" size="100%">25-30</style></pages><doi><style  face="normal" font="default" size="100%">10.5344/ajev.1996.47.1.25</style></doi><volume><style face="normal" font="default" size="100%">47</style></volume><issue><style face="normal" font="default" size="100%">1</style></issue><abstract><style  face="normal" font="default" size="100%">Charge densities of the major wine polysaccharides and of grape seed and wine polyphenols have been determined with a method developed by Mütek (Germany), relying on titration with a counter-charged polyelectrolyte associated to streaming potential measurements. Charge densities were determined in a model hydroalcoholic solution at pH 3.5 and in 10 mM KNO3 solutions, from pH 2 to 9. The polysaccharides tested — yeast mannoproteins, grape arabinogalactan-proteins (AGPs), and rhamnogalacturonan RG-II — carried negative charges in the wine pH range. The net charge density of yeast mannoproteins was shown to be related to their phosphorus content and to be pH-independent in the range tested (2 to 9). Absolute charge densities of AGPs and RG-II were related to the dissociation of the carboxylic functions of their uronic acids and increased dramatically in the pH range 2 to 5. Polyphenolic fractions, including native tannins isolated from grape seeds and polyphenolic fractions recovered from wine, carried no charges or negligible charges at pH 3.5. As a consequence, wine polysaccharides may establish electrostatic and ionic interactions, but such interactions will play little, if any, in the association of polyphenols with other components.</style></abstract></record></records></xml>