Capillary electrophoretic analysis of wine proteins. Modifications during the manufacture of sparkling wines

This paper reports a new electrophoretic method for the analysis of wine proteins. The method used for protein isolation and concentration was dialysis followed by lyophilization. Electrophoretic separation was carried out on an uncoated fused silica capillary of 57 cm total length, 50 cm effective length, and 75 mu m i.d., using 100 mM tris(hydroxymethyl)aminomethane (Tris)-HCl, pH 8.0, at 12 kV. Detection was at 214 nm. The protein fractions of sparkling wines after 3, 6, 9, 12, 15, 18, and 24 months of aging on yeast lees and of the must and the base wine from which they originated were studied. Eight peaks were separated in the must. During the first fermentation, both the intensity and the number of peaks were lower. In the first months of aging with yeast another reduction in the intensity of the peaks was observed, although new peaks appeared, probably corresponding to polypeptide forms released by the yeast. These results were compared with those achieved by native-PAGE.