Wine protein instability depends on several factors, but wine grape proteins are the main
haze factors, being mainly caused by pathogenesis-related proteins (thaumatin-like proteins and
chitinases) with a molecular weight between 10~40 kDa and an isoelectric point below six. Wine
protein stability tests are needed for the routine control of this wine instability, and to select the
best technological approach to remove the unstable proteins. The heat test is the most used, with
good correlation with the natural proteins’ precipitations and because high temperatures are the
main protein instability factor after wine bottling. Many products and technological solutions
have been studied in recent years; however, sodium bentonite is still the most efficient and used
treatment to remove unstable proteins from white wines. This overview resumes and discusses the
different aspects involved in wine protein instability, from the wine protein instability mechanisms,
the protein stability tests used, and technological alternatives available to stabilise wines with protein
instability problems.This research was funded by the Fundação para a Ciência e Tecnologia (FCT-Portugal) and Operational
Competitiveness Programme (COMPETE, Portugal) through the projects Chemistry Research Centre-Vila Real
(UIDB/00616/2020) and CIMO (UIDB/00690/2020).info:eu-repo/semantics/publishedVersio
