Fractionation of White Wine Proteins by Membrane Operations

Fractionation is a separation process in which a certain amount of a mixture is divided up into a smaller number of quantities or fractions with different molecular composition. Fractionation is based on the difference in specific properties between the individual components. Commonly equilibrium has to be aimed between the recovery of a specific compound and the desired purity of each fraction.

Proteins from white wines differ in molecular weight, ranging from 9 to 72 kDa, isoelectric point with pI between 3 and 9, hydrophobicity, degree of glycosylation, and thermal stability. Proteins can exhibit positive effects such as the stabilization of foam in sparkling wines, the interaction with aroma compounds, the protection of wine against precipitation of tartaric salts, and the interactions with other wine compounds such as ethanol, polyphenols, and polysaccharides. However, they are also involved in some aspects that can impair the acceptance of the final product by consumers, such as...