Varietal Differentiation of Must and Wines by Means of Protein Fraction

Abstract

Native electrophoresis, SDS electrophoresis, and isoelectric focusing were used to determine electrophoretic patterns of 10 grape musts and 14 varietal wines made from white grapes. Nine of the musts from the Macabeo, Xarel-lo, and Parellada grape varieties were fermented on an industrial scale under similar conditions. Five wines were produced in a pilot plant (500 L), with different inoculation of yeasts and with or without added SO₂ from the Malvar grape variety. The electrophoretic patterns obtained with the three techniques were similar for musts from the same variety, but different when musts from different varieties were compared. The electrophoretic patterns of the resulting wines were different from original musts. The electrophoretic patterns of the wines from the same variety were very similar in spite of the different conditions under which they were produced.