Heat-unstable protein removal by different bentonite labels in white wines

The relationship between heat-unstable wine proteins and bentonite fining is still a matter of debate. Some authors have suggested that bentonite removes protein according to matrix parameters, but others have described it as selective for some protein classes. The aim of our work was to characterize the fining effects of five different types of activated sodium bentonite on two international white wines (Chardonnay and Sauvignon blanc). The physical properties of the bentonite samples and the general wine characteristics were determined, and protein removal was evaluated with gradient SDS-PAGEs, protein quantification and subsequent band identification by MALDI-TOF mass spectrometry. For the Chardonnay and Sauvignon blanc tested in the study, fining with specific bentonite labels to remove select residual proteins, some of which are potential allergens, was very promising. The removal of a single protein by bentonite affected the wine's thermal stability.