Sorption of aroma compounds by commercial specific yeast derivatives and the influence of polyphenols

Abstract

Specific inactivated yeast derivatives (SYDs) from S. cerevisiae are obtained through thermal, mechanical, and enzymatic processes and are used to enhance wine quality. Their impact on wine sensory properties varies depending on SYD type, fraction, matrix interactions and time, as they can modify aroma compounds’ volatility or concentration (1). Some studies have examined SYDs’ sorption of undesirable aroma compounds (2) but the sorption of key aroma compounds remains underexplored, particularly in relation to wine macromolecules such as polyphenols. Furthermore, no comparative study was found on the sorption capacity of different SYDs.

The aim of this research was to evaluate the sorption capacities of different SYDs in model wine conditions and to investigate the influence of polyphenols on such interactions with aroma compounds.

Three selected SYDs provided by Lallemand — inactivated yeast (IY), selected cell walls (CW), yeast protein extracts (YPE) — were fractionated based on solubility criteria. Insoluble fractions were added at 1 g/L to model wines containing 21 aroma compounds (esters, terpenoids, norisoprenoids, alcohols, aldehydes, phenols, sulphur compounds) in order to investigate their sorption according to functional groups and structural characteristics. Equilibrium sorption time was determined at 15°C, under constant agitation by monitoring free aroma concentrations in the supernatant over time. Aroma compounds were quantified by GC-MS (SIM mode) using external calibration for each compound, and after their liquid extraction with dichloromethane in presence of specific internal standards. Under equilibrium conditions, the impact of polyphenols was assessed using a 2 g/L polyphenol pool isolated from Syrah wine.

Sorption equilibrium was reached within 4 hours, and all insoluble fractions of SYDs exhibited aroma sorption capacity. The sorption capacity of the insoluble fraction of SYDs was influenced by their physicochemical properties and YPE showed the highest capacity, followed by IY and CW. Aroma compounds hydrophobicity played a key role since the most hydrophobic compounds within chemical groups (except for norisoprenoids), were preferentially sorbed, but structural properties have also shown an effect. Notably, polyphenols reduced sorption for some compounds, highlighting the importance of the wine matrix in SYD-aroma interactions. These findings provide insight into SYDs’ functionality and their potential application in aroma modulation during winemaking processes.

References

[1] Rigou P, Mekoue J, Sieczkowski N, Doco T, Vernhet A. Impact of industrial yeast derivative products on the modification of wine aroma compounds and sensorial profile. A review. Food Chemistry. 2021 Oct;358:129760.

[2] Nieto-Rojo R, Ancín-Azpilicueta C, Garrido JJ. Sorption of 4-ethylguaiacol and 4-ethylphenol on yeast cell walls, using a synthetic wine. Food Chemistry. 2014 Jun 1;152:399–406.