CHARACTERIZATION OF THE PROTEIC AND THE PHENOLIC FRACTION IN TARTARIC SEDIMENTS FROM WINES

The proteic and phenolic fraction precipitated along with potassium bitartrate crystals during the different stages of Spanish sparkling wine-making were studied. Electrophoretic and chromatographic techniques, together with chemical analysis, were carried out to determine the nature and physico-chemical properties of the organic compounds present in sediments. The phenolic compounds were more abundant and highly polymerized in the samples obtained from cold stabilization. Cinnamic acids esterfied with tartaric acid comprised the main low molecular weight phenolic compounds in all the samples. There was a propensity for certain proteins to precipitate out of the wines, given that the main bands detected in the tartrates presented higher electrophoretic mobilities than those in the wines themselves. The distribution of the molecular weights of the proteins in the tartrates differed from that of the proteins in the wines. The molecular weights of the main bands obtained using SDS-PAGE were smaller than 20 000 or higher than 50 000 in the case of the proteins from the tartrates, whereas the molecular weights of the main bands for the proteins in the musts and in the wines ranged between 20 000 and 40 000.