Effect of Ion-Exchange Adsorption on the Protein Profiles of White Wines

The protein profiles of two different wines of Austrian and Portuguese origin, characterized by HPLC fractionation, were compared before and after ion-exchange adsorption of the wine proteins. Conventionally used sodium bentonite and three alternative nonswelling commercial resins were used. Profile similarity was assessed in terms of the Euclidean distance of all protein peak areas for two samples, and of the average of the differences between each protein peak percentile area between two samples. In general, the differences between profiles for the same material increased with the amount of wine adsorbed, showing that some protein fractions were more easily adsorbed than others. Differences between the adsorption with bentonite or with the alternative adsorbents were not statistically significant, with the exception of one adsorbent in one of the wines, where protein removal was more extensive.