Separation of polyphenolic compounds by ultrafiltration of Bordo grape (Vitis labrusca var. Bordo) skin extract

Separation of the phenolic compounds from the acidified aqueous extract with 2% (w/v) citric acid from Bordo grape skin was carried out through ultrafiltration using polyestersulfone membranes with molecular weight cutoff 10 and 30 kDa. The performance of the membranes at different transmembrane pressures of 1.0 to 3.5 bar and temperatures of 25, 35 and 45 °C showed better separation conditions at 25 °C and 3.5 bar of transmembrane pressure. The results showed hydraulic permeability for the new membranes of 10 and 30 kDa of 10.96 and 20.52 L.m-2.h-1.bar-1, respectively. The highest membrane resistance was the polarization by concentration, compared with the total resistance, from 80 to 90% and from 60 to 90% for the 10 kDa and 30 kDa membranes, while the fouling resistance was the lowest, from 1 to 3% and 1 and 16% in membranes of 10 and 30 kDa.

Keywords: ultrafiltration, membranes, fouling, polyphenol.