Analysis of lignin-derived phenolic compounds and their transformations in aged wine distillates

- CE conditions were set up to separate lignin-derived phenolic aldehydes and acids.
- Performance characteristics of the method are determined.
- The mechanism of transformations during long ageing of wine distillates is analyzed.
- Lignin-derived phenolics can be used to discriminate aged distillates.

Aromatic aldehydes and acids derived from lignin were studied by capillary zone electrophoresis in barrel matured wine distillates used in brandy production. Different conditions of analysis were applied to set up the best separation and reproducibility. The optimal separation was performed using 25 mM borate buffer containing 8% v/v ethanol as modifier. Total amount of guaiacol-type compounds (coniferaldehyde, vanillin, and vanillic acid) and syringol-type compounds (sinapaldehyde, syringaldehyde, and syringic acid) increased with increasing ageing time for distillates aged from 1 to 25 years. Sum of concentrations of syringic and vanillic acids can be also used for characterizing aged distillates according to their ageing level. The developed analysis method is simple, precise and cost efficient. It provides good separation efficiency, and it is ideally suited for the analysis of aged wine distillates for determination of their overall quality, approximate ageing time and signs of counterfeiting.