Elucidating white wines peptides: An analytical breaktrough

Abstract

The chemistry of wine is particularly complex due to biochemical and chemical interactions that significantly modify its organoleptic characteristics and stability over time. Aging on lees is a well-known practice during which various compounds are released, ensuring wines oxidative stability and its overall sensory quality [1,2]. Peptides are key compounds extractible from wine lees known for their tensioactivity [3], antimicrobial [3] and their antioxidant activities [4,5], however their chemical diversity is poorly studied. Our research team is interested in characterizing and evaluating the evolution of wine peptidic fraction during aging on lees, to determine how their different physico-chemical properties (polarity and size) influence the overall quality of the wine. In that respect, we have developed a combined SPE / LC-MS analytical methodology for overcoming the challenges associated with peptides separation and detection. Method optimization was carried out using a rich pool of peptides generated after BSA enzymatic digestion in model wine solution. Two SPE cartridges, a reversed-phase and a cation-exchange, were tested after adapting elution conditions. Results show that the extraction efficiency varied between the two approaches. The cation-exchange cartridge provided higher overall recovery and helped to overcome some limitation of reversed-phase cartridge, related to the loss of hydrophilic and small peptides. Five different LC columns were compared, including reverse phase (RP) and hydrophilic interaction (HILIC), with different gradient conditions (solvent pH and composition in ACN, elution time) as well as sample solubilization conditions. The results show that one of the columns, combined with specific conditions, including elution gradient for RP and elution gradient, mobile phase composition, and pH for HILIC, demonstrated superior performance. The separation performance was characterized by an increased number and a better distribution of detected features throughout the analysis time. In detail, in a total of respectively 4308 and 2964 detected features for RP and HILIC columns, only 1475 (34.24%) were in common. These results show a good complementarity between RP and HILIC separation modes indicating the use of both for a more complete description of wines peptidic fraction. To conclude, the proposed analytical approach shall allow complete description of peptide composition with highly repeatable annotations and quantification of peptides even in mixed hydrolysates.

References

[1] Alexandre, H., Guilloux-Benatier, M. (2006). Aust. J. Grape Wine Res, 12, 119–127.

[2] Alexandre, H. (2022). Manag. Wine Qual. Second Ed., Woodhead Publishing, 213–244.

[3] Moreno-Arribas, M.V., Pozo-Bayón, M.Á., Polo, M.C. (2009). Wine Chem. Biochem., Springer, New York, NY, 191–212.

[4] Romanet, R., Sarhane, Z., Bahut, F., Uhl, J., Schmitt-Kopplin, P., Nikolantonaki, M., Gougeon, R.D. (2021). Food Chem, 355, 129566.

[5] Bahut, F., Romanet, R., Sieczkowski, N., Schmitt-Kopplin, P., Nikolantonaki, M., Gougeon, R.D. (2020). Food Chem, 325, 126941.