White Wine Protein Instability: Origin, Preventive and Removal Strategies

Abstract

White wine protein instability depends on several factors, where Vitis vinifera pathogenesis-related proteins (PRPs), namely chitinases and thaumatin-like proteins, present an important role. These proteins can be gradually denatured and aggregate during wine storage, developing a light-dispersing haze. At present, the most efficient process for avoiding this wine instability is through the removal of these unstable proteins from the wine before bottling. To remove unstable white wines proteins, the sodium bentonite fining is the most used treatment, however, many alternative techniques such as ultrafiltration, the application of proteolytic enzymes, flash pasteurisation, other adsorbents (silica gel, hydroxyapatite and alumina), zirconium oxide, natural zeolites, chitin and chitosan, carrageenan and the application of mannoproteins have been studied. This chapter overviews the factors that influenced the white wine protein instability and explored alternative treatments to bentonite to remove white wine unstable proteins.