Wine amino acids of four autochthonous grape varieties from Southwest France: influencing factors and role in taste perception

The hundreds of molecules present in wine play an important role in its complexity, including amino acids. While numerous studies exist on the role of amino acids in musts, few studies focus on wines. In the present study, the amino-acid profiles of a large sample of monovarietal white wines from three vintages of varieties from Southwest France (Colombard, Gros Manseng, Len de l’el, and Mauzac) were evaluated. Physicochemical oenological parameters were first analysed for each wine, revealing significative differences between grape varieties and within each variety. These differences included the organic nitrogen content, which was studied in greater detail. After derivatisation, the primary amino acids were identified and quantified using high-performance liquid chromatography (HPLC) with UV detection. The wines from the four grape varieties predominantly contained the same amino acids (proline, arginine, alanine and lysine) as those found in wines from other varieties. The amino acid composition in wines can be strongly influenced by various factors, such as the ripeness of the grapes, the grape variety itself, or certain parameters like vineyard treatments. In this study, it was possible to differentiate between the varieties by their proline and glutamic acid contents; both these amino acids were analysed to assess their impact on taste perception thanks to a naïve panel fitted with a nose clip, and a difference was perceived for proline. Further studies would be necessary to better understand their effect on gustatory perception.