STUDY OF MACROMOLECULES IN CHAMPAGNE WINES

In Champagne wines, polypeptides and polysaccharides were separately isolated, concentrated and either quantified or analysed by gel permeation chromatography. Polypeptides were revealed with G250 Coomassie blue, C5 carbohydrates polymers with orcinol, C6 carbohydrates polymers with anthrone and uronic acids polymers with m-hydroxyphenylphenol. Musts contained from 25 to 95 mg/l polypeptides and from 60 to 440 mg/l polysaccharides and wines contained from 10 to 30 mg/l polypeptides and from 10 to 120 mg/l polysaccharides. Musts and wines fining with bentonite and must enzyme clarification with beta-glucanase were used to investigate the qualitative distribution of macromolecules by gel permeation chromatography. Three main pools of polypeptides were found : greater than 20 10(6), 17 000 and 3 000 daltons (d). The intermediate fraction was removed by bentonite fining. Its glycoconjugated nature was proved by SDS-PAGE electrophoresis, followed by nitrocellulose gel transfer and concavalin A reaction. Polysaccharides profiles showed a complex picture of C5 and C6 carbohydrates and uronic acids polymers. Their molecular weights varied from 10(6) to 10 000 d with a main peak at 80 000 d. Depending on the wines, there were fractions at 650 000, 460 000, 320 000 and 15 000 d. The 460 000 daltons fraction was hydrolysed by beta-glucanase and the fraction between 300 000 and 10(6) d is removed by bentonite.