Effect of antioxidant supplementation on the polysulfides of white wines

Sulfur chemistry remains one of the most intriguing and elusive fields in wine science. In particular, the possibility for symmetric and asymmetric glutathionylated and cysteinylated polysulfides to act as latent reservoirs for H2S warrants new research on the factors influencing the formation and accumulation of these molecules. The present research studies the impact of pre-fermentative additions of commonly employed antioxidants: glutathione, ascorbic acid, and ellagic tannin. Musts from four different white grape varieties (Riesling, Pinot gris, Pinot blanc, and Johanniter) were analysed using our comprehensive HPLC-HRMS method. Seven symmetric and asymmetric glutathionylated (G) and cysteinylated (C) polysulfides (GS2C, GS3C, GS4C, GS3G, GS4G, CS3C, and CS4C) were detected in the final 48 wine samples. Finally, this work describes for the first time the impact of an accelerated ageing of wine on the polysulfides present. All variables (Must, Treatment, and Time) were shown to impart statistically significant effects (p = 0.0001) in the PERMANOVA model. The PCAs based on polysulfides present in young and aged wine explained more than 80% of the total variance for each grape variety and showed that Asc or GSH additions have tend to produce lower levels of polysulfides in the resultant wines.