From Vine to Vintage: NMR Metabolomics of Young and Mature Wine and Grape Ale

The chemical profiles of young and mature wines produced from three grape varieties Merlot, Mavrud and Sauvignon blanc were analyzed using 1H nuclear magnetic resonance (NMR) spectroscopy and advanced statistical methods. Moreover, grape ales, a hybrid of beer and wine, were subjected to analysis in order to facilitate a comparison of their composition with that of traditional wines. A total of 37 compounds were identified and quantified, and orthogonal partial least squares discriminant analysis (OPLS-DA) models were employed to distinguish the chemical profiles of young and mature wines, as well as those of grape ales. The findings demonstrate that the fermentation and aging processes result in the formation of distinctive chemical signatures in wines, with key compounds such as shikimic acid and fructose contributing to this differentiation. The identified compounds comprise seven alcohols (2,3-butanediol, glycerol, isobutanol, isopentanol, myo-inositol, 1-propanol, 2-phenylethanol), six organic acids (galacturonic, citric, lactic, malic, shikimic, succinic), three amino acids (alanine, proline, tyrosine), four sugars (arabinose, fructose, galactose), coutaric acid and acetoin. The levels of these 22 components enabled the successful differentiation of young and mature wines among the three grape varieties. These results highlight significant chemical differences between grape ales and wines, thereby underscoring the potential of grape ales as an innovative fermented beverage.