AF4 – UHPLC: two-dimensional separation of macromolecules in monovarietal white wines from South-Western France

Abstract

The French south-west region is unique in having over 300 grape varieties for wine production, 120 of which being indigenous. In this area, Gers (20,362 hectares, 2022) and Tarn (6,274 hectares, 2022) produce dry white wines from typical grape varieties among which Colombard, Gros Manseng, Mauzac and Len de l’el. Wines from each of these varieties have their own sensory identity. To differentiate them at macromolecular level, asymmetrical flow field flow fractionation (AF4) was used. This method can only separate wine macromolecular populations by size. The aim of this work was to identify the composition of each population in white wines by developing an on-line system combining AF4 and high-resolution liquid chromatography (UHPLC). For this purpose, 69 wines were collected and first analyzed by Fourier Transform Infrared Spectroscopy (FTIR) to determine the conventional enological parameters (alcohol content, titratable acidity, pH…) [1]. After statistical processing by hierarchical ascending classification, 3 wines were selected for each variety. A sensory “Flash Profile” test was first set up using an expert panel to differentiate the 12 white wines according to their specific mouthfeel [2]. These wines were injected into AF4 coupled with ultra UHPLC. To validate the system, two standards (thaumatin and mannoproteins) naturally present in the wines were injected. The results showed that each variety had its own 2D mapping. Colombard and Gros Manseng grape varieties showed different types of proteins, with varying degrees of affinity with the column. On the other hand, Len de l’el and Mauzac varieties stood out for their total absence of proteins but their presence of mannoproteins [3]. This innovative technique can be of considerable interest for the separation of complex mixtures, such as wine but also milk or beer, offering the advantage of differentiating compounds of distinct sizes but with the same hydrophobicity: it could provide an accurate representation of the macromolecular profile of various matrices. Understanding the contribution of these macromolecules in white wines mouthfeel perception is another perspective of this study.

References

1. Figué, A., Violleau, F., & Gosset, M. (2025). Wine amino acids of four autochthonous grape varieties from Southwest France: Influencing factors and role in taste perception. OENO One, 59. https://doi.org/10.20870/oeno-one.2025.59.1.8074

2. Figué, A., Gaucher, M., Hennetier, M., Violleau, F., & Gosset, M. (2025). Differentiation of monovarietal white wines from four indigenous grape varieties of Southwest France: Gustatory (Flash profile) and macromolecular (Asymmetrical flow-field flow fractionation) profiling. Food Chemistry, 485, 144513. https://doi.org/10.1016/j.foodchem.2025.144513

3. Figué, A., Gosset, M., & Violleau, F. (2024). AF4-UHPLC: Two-dimensional separation of macromolecules in four white wines from South-Western France. Journal of Chromatography A, 1738, 465456. https://doi.org/10.1016/j.chroma.2024.465456