Is the use of pure glutathione an alternative to sulphur?

Glutathione (GSH) is a natural peptide and grape-derived antioxidant that has been proposed as an alternative to sulfur dioxide in wine. This project focused on the addition of pure GSH prior to or during fermentation. Its consumption during wine production was quantified and the impact of process variables such as grape juice nitrogen concentration and the degree of protection from oxygen on GSH concentration was assessed in both laboratory- and pilot-scale trials. It was demonstrated that low concentrations of GSH have little impact when added prior to fermentation and that higher addition rates caused undesirable sensory outcomes.

The findings may disappoint winemakers keen to pursue pure glutathione as an alternative to sulfur dioxide, the antioxidant most commonly used to protect wine and preserve quality. It does, however, confirm that seeking approval for pure glutathione as a permitted winemaking additive is not worth pursuing*.

* Glutathione-enriched inactivated dry yeast is an approved processing aid for winemaking (OIV & FSANZ) but pure glutathione is not approved as a processing aid or as an additive.
 

The project’s Final Report is available here.

Source: Wine Australia