Insights on colour stabilization towards yeast derivative products

Abstract

The colour stability of red wine is a desired and complex feature affected by anthocyanin structure and concentration, copigmentation phenomena, and interactions with other wine macromolecules, such as polysaccharides. The increased content of the latter compounds may help to stabilize the colour and, in this context, the use of yeast derivative products (YDPs) can represent a useful tool (1). However, the use of YDPs to modulate colour expression needs further investigations since the effect that YDPs on colour remains controversial and highly dependent to both wine and YDP. In this study, six YDPs with different physicochemical characteristics and belonging to different classes were evaluated for their impact on colour evolution and anthocyanin polymerization in two Italian red wines with relevant differences in phenolic profiles: Nebbiolo and Sangiovese wines. The wines, were supplemented with YDPs at 40 g·hL⁻¹ and stored under accelerated aging conditions (35 ± 2 °C) for 10 weeks. Samples were collected after 3, 6 and 10 weeks and analysed for total phenolic index, anthocyanin profile and polymerization, and colour indexes. The two wines showed markedly different responses to YDP addition. In particular, a more pronounced effect was observed in Nebbiolo wine, showing higher levels of free anthocyanins and lower total polyphenols content in comparison to Sangiovese wine. One of the assayed inactivated yeasts (I1) promoted anthocyanin polymerization, leading to an increase of total polymeric pigments and colour intensity. On the contrary, mannoproteins MP4 appeared to limit the polymerization, as higher chroma and a* values and lower absorbance value at 620 nm were found. This effect could be correlated to the polysaccharide composition of YDPs; MP4 showed the major content of free polysaccharides exerting a protective effect towards monomeric anthocyanins. In contrast, little changes in polymeric pigment distribution were observed in Sangiovese wine added with YDPs. The negligible impact of YDPs can be ascribable to the higher levels of copigments already detected in Sangiovese wine. Overall, the results confirmed that YDP effects on wine colour depend strongly on the phenolic composition and on the specific properties of YDPs. Among the YDPs investigated, I1 and MP4 showed the most consistent and contrasting behaviours, highlighting the need for targeted YDP selection based on wine composition to optimize colour stabilization strategies.

References

1. Alcalde-Eon, C., García-Estévez, I., Puente, V., Rivas-Gonzalo, J., & Escribano, T. (2014). Color stabilization of red wines: A chemical and colloidal approach. Journal of Agricultural and Food Chemistry, 62(29):6984-94. https://doi.org/10.1021/jf4055825

Funding

Dal Cin S.p.a.