Exploring 2-aminoacetophenone contents in sparkling wines based on analytical data and statistical modelling

The influence of the second fermentation step on sparkling wine aroma was investigated with respect to the content of 2-aminoacetophenone (AAP) as an indicator substance for the atypical ageing off-flavour (ATA). AAP contents of aged sparkling wines and their corresponding base wines (Riesling and Chardonnay variety) were determined by means of multidimensional gas chromatography using a stable isotope dilution assay. The majority of sparkling wines were lower in AAP in comparison with their corresponding base wines. Explorative and predictive statistical analyses of the resulting AAP content in sparkling wines were performed concerning the influence of the parameters lees contact time, yeast strain, base wine AAP concentration and total phenolic contents. Both statistical approaches yielded good fits with AAP concentration of the base wine being the predominant factor. Although it was possible to explain the changes in AAP concentrations on the basis of how total phenolics changed during second fermentation, predicted AAP trends did not hinge upon the amount of total phenolics present in a base wine. Unpressurised model fermentations were a promising technological alternative to study the development of AAP in sparkling wines. Altogether, this study presents a multidisciplinary approach to master the challenging task of ATA risk assessment in base wines, which at present rather accesses the sparkling wine producer’s individual experience.