Protein Fraction Analysis of White Wine by FPLC

This paper proposes a method, using FPLC, for separating white wine proteins into several fractions. Gel filtration followed by cationic exchange were used for quantifying and separating the different protein fractions of wine. Four peaks were detected by gel filtration, but SDS-PAGE indicate that only peak 2 and peak 3 were proteins. Subsequent analysis of peaks 2 and 3 by cationic exchange chromatography and SDS-PAGE indicate that peak 2 is a single protein of 60 KDa and peak 3 is an ensemble of several proteins of similar molecular weights and different electric charges. We have also studied the fate of proteins throughout the winemaking process, and this study shows that total protein content decreases. This decrease was much greater in the proteins with high positive electric charge.