In 2023, Dal Cin Spa launched a PhD research project in collaboration with the Department of Food, Environmental and Nutritional Sciences (DEFENS) at the University of Milan. The project, named WINNY, aims to explore the compositional and application aspects of yeast derivatives in depth, with the goal of providing winemaking tools that meet current market demands and requirements:

• allergen-free;
• free from synthetic products;
• free from animal-derived products;
• reduced subtractive processing.

In this article, we will examine the role of certain derivatives in preventing oxidation phenomena and facilitating the stabilization of coloring matter, with a focus on rosé wines.

Yeast Derivatives

The term “yeast derivative” encompasses a range of products (see Fig. 1) that differ in production technology, composition, and oenological properties.

As part of this study, 9 inactive yeasts, 2 cell walls, 6 autolysates, 5 extracts, and 6 mannoproteins were characterized and tested.

Characterization of Derivatives

All derivatives were characterized, with specific quantification of:

• Nitrogen content (in various forms) and amino acid profile;
• Reduced glutathione (GSH) concentration;
• Total and cell-wall cysteine (Cys) concentration;
• Antioxidant capacity, measured via three different assays (FRAP, DPPH, ABTS);
• Polysaccharides.

Yeast Derivatives and Antioxidant Protection

As shown in previous studies, among the tools available to winemakers to ensure the proper evolution of white and rosé wines, Harmony® Vitality is undoubtedly one of the top performers. It provides protection equal to or greater than $\text{SO}_2$ and reduced glutathione by counteracting dissolved $\text{O}_2$, thereby protecting color and aromas during aging and storage (see Graph 1).

As shown in Graphs 2 and 3, the GSH and Cys concentrations in Harmony® Vitality are significantly higher than the average found in other derivatives. This directly translates into higher antioxidant capacity, as measured by three different methods (see Graph 4).

Yeast Derivatives and Color Protection

Yeast derivatives play a positive role in color protection through two distinct mechanisms: they protect anthocyanins (red and rosé wines) and catechins (white and rosé wines) from oxidative degradation, and they act as protective colloids to prevent the precipitation of coloring matter (red and rosé wines).

The first mechanism is characteristic of Harmony® Vitality (see Graphs 5 and 6); the second mechanism is leveraged by the mannoproteins in Harmony® Refine (see Graphs 7 and 8).

Conclusions

Yeast derivatives serve as versatile tools across all winemaking stages: they act as nutrients for yeasts and bacteria, fining agents for musts and wines, alternatives to $\text{SO}_2$ for oxidation management, protective colloids against color precipitation, and aids for tartrate and protein stability. The WINNY project continues to investigate the specific properties of numerous derivatives to identify the most suitable solutions for individual applications. Ultimately, it aims to deliver effective technological options tailored to various winemaking styles—whether conventional, low/zero-sulfite, vegan, organic, allergen-free, or aimed at minimizing subtractive treatments that can strip a wine’s character.