Comparative analysis of aroma profiles and determination of key constituents in organically and conventionally produced white wines

This study compares the aromatic profiles of Czech white wines produced under conventional and organic practices and identifies the volatile compounds most relevant for distinguishing these production systems. Seventy-eight wines (49 conventional, 29 organic) were analyzed by HS-SPME/GC-FID, with GC-MS used for compound identification, and data were evaluated using OPLS with the logarithm of likelihood ratio as the response variable. The calibration model (n = 122) explained 96.7% of the total variation and achieved 92.3% cross-validated predictability, with both sensitivity and specificity reaching 1.000 for conventional and organic wines; external validation (n = 34) confirmed perfect classification accuracy (RMSE = 0.17). Among the 20 most influential predictors, 16 volatile compounds were identified as significant markers. Organic wines exhibited substantially higher concentrations of malolactic fermentation indicators, with ethyl lactate and isoamyl lactate averaging 39-fold and 7-fold higher levels, respectively. Conversely, hexyl acetate was 9-fold more abundant in conventional wines, which aligned with the contrasting hexanol:hexyl acetate ratios (48.0 organic vs. 4.5 conventional). Organic wines also contained 29-fold higher caprylic acid, accompanied by a markedly different ethyl caprylate:caprylic acid ratio (280 vs. 20). These compositional patterns provide a robust chemical fingerprint enabling reliable differentiation of production systems.