Wine protein stabilization by Zirconia

The presence of turbidity in bottles of white wine is a major defect in quality, making it undesirable for the consumers. This phenomenon is due to the insolubility of certain wine proteins during storage, making it necessary ensure its elimination. The traditional procedure for stabilizing white wines against protein turbidity is through the addition of bentonite. However, this treatment is not specific for the unstable proteins, also eliminating color, aromas and other macromolecules that could be involved in a quality loss in the final wine. Another feature of this treatment is that it is discontinuous, and generates a significant amount of residue (3-10% v/v), with their corresponding environmental impact and costs of operation. Therefore, it is necessary to develop new procedures that minimize these negative aspects. The use of porous solids based in metallic oxides to remove proteins is an interesting possibility for protein stabilization of white wines, since a stabilizing deep filtration can be considered from a standpoint of process. This chapter is an overview in the protein stabilization of white wines, using zirconia as a filter medium or as adsorbent material during the fermentation.