Cellulose Gum: a new additive for wine tartaric stability. Tentative of structures determination involved in the haze formation after CMC addition in wine
Résumé
Cellulose gum (or sodium carboxymethylcellulose / CMC) is a new additive permitted by the European Community for tartaric stabilization (maximum dosage: 10g/HL). CMC is known to have a high eciency for potassium bitartrate and calcium tartrate crystallization inhibition in white and sparkling wines. Hypotheses suggest an inhibition of the nuclei growth at the beginning of their formation. However some problems remain, such as the formation of a low increase of the turbidity in white wine (from 0,1 to 0,4 NTU at room temperature) requiring a ltration step and the formation of a high lumps volume when CMC is used in some red wines. The goal of the following experiments was to determine which molecules are involved in the haze formed in white or red wines. 1. On white wines: A unique Sauvignon wine is treated from 0 up to 600mg/L of activated bentonite. After ltration, each batch was added (or not) with 100mg/L of CMC previously dissolved in tap water (conc.:50g/L). After 1 week of storage at 13°C, samples were heated at 80°C during ½ h and then stored at RT during 24h before running turbidity. 2. On red wines: 1L of red wine (blend of Cinsault, Merlot and Cab. Sauvignon) was added with 100mg/L of CMC (see above) and stored at-4°C for 4 days. After this time, the wine showed a high level of red clouds. At negative temperature, the deposit was ltered on 0.2 µm nitrocellulose lter membrane and extensively washed with a hydro-alcoholic solution (12% ethanol v/v-pH: 3,5/HCl) kept at-4°C. The membrane was then dried under vacuum and the deposit was collected and exchanged 3 times with D2O for H1-NMR study (HRMAS).
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