IMPROVED SIZE-EXCLUSION HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHOD FOR THE SIMPLE ANALYSIS OF GRAPE JUICE AND WINE POLYSACCHARIDES

A size-exclusion HPLC method was developed for the separation and quan tification of grape juice and wine polysaccharides. Polysaccharide ext raction was carried out by precipitation and two chromatographic proce dures were tested with the polysaccharide precipitate solution: direct injection, and fractionation of non-negatively charged (NCPS) and neg atively charged (CPS) polysaccharides using an anion-exchange cartridg e, before injection. The direct procedure (injection of the precipitat e solution on two GPC columns and RI detection) was chosen, because th e sum of areas of NCPS fractions represented 1.42% of the total area ( sum of areas of NCPSs plus sum of areas of CPSs). The precision, linea rity, sensitivity and accuracy of this method were established. Identi fication was performed by pectins and polyacrylic acids. The concentra tion of each polysaccharide identified according to the molecular mass was obtained by considering that the whole area (100%) contains the t otal number of polysaccharides determined by colorimetric method. Thre e polysaccharides were separated in grape juice (19 000; 2000 and 1000 , approximately), whereas seven polysaccharides were obtained in wine (45 000; 19 000; 12 000; 7000; 4000; 2000 and 1000, approximately). (C ) 1998 Elsevier Science B.V. All rights reserved.